3 A B C

Filters and washers : 1 - Washer 2 - Metal filter 3 - Flow regulator 4 - Plastic filter 5, 6 & 7 - Washers

p r q s

Pla 105c
THEMA F SB 18 THEMA F SB 23 E
From left to right, the fixing jig comprises: A - Heating return with isolating valve (m). C - Heating flow with isolating valve (q), drain screw (r) and safety valve (s). 3 E - Gas service cock. 11

m p r q s 7 E

Pla 116b

Diagram 5

DOMESTIC HOT WATER SYSTEM DESIGN
Copper tubing or plastic Hep2 O may be used for the domestic hot water system. Unnecessary pressure losses should be avoided. The boiler may operate with a minimum supply pressure of 0,3 bar but under a reduced flow rate. Optimum performance will be obtained from a supply pressure of 1 bar. The flow restrictor must be fitted in the cold water inlet during installation. This limits the flow through the boiler to a maximum of 12 l/min.

HEATING SYSTEM DESIGN

The THEMA F boiler is compatible with any type of installation. Heating surfaces may consist of radiators, convectors or fan assisted convectors. Pipe sectional areas shall be determined in accordance with normal practices, using the output/pressure curve (diagram 3). The distribution system shall be calculated in accordance with the output requirements of the actual system, not the maximum output of the boiler. However, provision shall be made to ensure sufficient flow so that the temperature difference between the flow and return pipes be less than or equal to 20C. The minimum flow is 500 l/h. The piping system shall be routed so as to avoid any air pockets and facilitate permanent venting of the installation. Bleed fittings shall be provided at every high point of the system and on all radiators. The total volume of water permitted for the heating system depends, amongst other things, on the static head in the cold condition. The expansion vessel on the boiler is pressurised at 1 bar (corresponding to a static head of 5 m w.g.) and allows a maximum system volume of 140 litres for an average temperature of 75C and a maximum service pressure of 3 bar. This pressure setting can be modified at commissioning stage if the static head differs. An additional expansion vessel can be fitted to the system if required, see diagram 6. Provision shall be made for a drain valve at the lowest point of the system. Where thermostatic radiator valves are fitted, not all radiators must be fitted with this type of valve, and in particular, where the room thermostat is installed. In the case of an existing installation, it is ESSENTIAL that the system is thoroughly flushed prior to installing the new boiler using a proprietary product such as Fernox or Sentinel. Contact the product manufacturers for specific details. Filling the system Provision must be made for filling the system at low level. The use of a WRC approved filling loop is strongly recommended, connected as shown in diagram 6.

PIPING SYSTEM INSTALLATION
Heating system connections - Pipe diam 22 mm Hot water system connections - Pipe diam 15 mm Gas connection - Pipe diam 22 mm Safety valve discharge - Pipe diam 15 mm Safety valve discharge WARNING. It must not discharge above an entrance or window or any type of public access area. Connect the safety valve discharge pipe to the boiler, the discharge must be extended using not less than 15 m o.d. pipe, to discharge in a visible position outside the building, facing downward preferably over a drain. The pipe must have a continuous fall and be routed to a position so that any discharge of water, possibly boiling or steam, cannot create any danger to persons, damage to property or external electrical components and wiring. Tighten all pipe connection joints. Gas connection The supply from the governed gas meter must be of adequate size to provide a constant inlet working pressure of 20 mbar (8 in w.g.). To avoid low gas pressure problems, it is recommended that the gas supply is connected using 22 mm pipe. On completion, the gas installation must be tested using the pressure drop method and purged in accordance with the current issue of BS6891. Gas Safety (Installation and Use) Regulations In your interests and that of gas safety, it is the law that ALL gas appliances are installed and serviced by a competent person in accordance with the above regulations.
Water connection Connect the water pipes to the fixing jig using the copper tails supplied, see diagram 5. Warning: To prevent damage to the isolating cocks, do not solder joints or fittings with the copper tails connected. Connect the system pipework to the boiler observing the correct flow and return format as shown in diagram 6.
Additional expansion vessel (if required)

Boiler

Domestic water

Tundish (supplied)

Minimum 22 mm diameter Return Heating circuit Flow control valve Bypass valve Filling point

Diagram 6

Sch 173

Drain point

Cold supply
Pressure reducing valve (supplied)

BOILER LOCATION

Clearances The position of the boiler must be such that there is adequate space for servicing. The recommended clearances are: 40 mm either side of the boiler. 600 mm at the front of the boiler. 300 mm below the boiler. Fixing jig The fixing jig comprises three parts: 1) The connecting plate which allows the connection and soundness testing of all the pipework before the boiler is fitted and helps support the weight of the boiler. 2) The hook which supports the weight of the boiler. 3) The template which ensures the hook and connecting plate are correctly fitted relative to one another. Place template on wall in required position, making allowances for the necessary clearances etc., see diagram 7. Note: It is permissible to install the boiler with reduced clearances at the bottom and sides of the boiler PROVIDING that adequate consideration is given for Servicing/Repairs at a later date. If any doubt exists, contact the Saunier Duval Technical Helpline 01773 828400. Mark the position of the holes for the hook and connecting plate. Drill, plug and fix the connecting plate and hook to the wall using suitable screws. Check that both the hook and connecting plate are level. If the boiler is not installed immediately, protect the various couplings to prevent any ingress of foreign materials e.g. plaster, paint etc. Terminal position The minimum acceptable spacings from the terminal to obstructions and ventilation openings are shown in diagram 8.

Diagram. 10

Diagram. 9
REAR OUTLET FLUE INSTALLATION
The boiler is supplied for rear outlet flue connection. Alternatively, the boiler is designed to allow the flue system to be connected to the top of the boiler, top outlet flue connection. For top outlet flue connection, refer to 'Top outlet flue installation' Rear outlet flue - kit 86151 The rear outlet flue system consists of two parts, a white painted outer pipe and an aluminium inner, they are positively locked together when assembled. The flue kit 86151, see diagram 11, is 1000 mm long and comprises: - Outer pipe... A - Inner pipe... B - External rubber sealing collar.. C - Flue elbow.. D - Internal flange.. E - 'O' rings... F - Screws.. G - Rubber collar.. H - Clamp and seal..I - Gasket.. J

Ins 020

A - Direct rear outlet flue Mark correct position of hole from template using hole between hook and connecting plate.

Pho 422

Diagram 11

Ins 021

B - Rear outlet side flue Mark the horizontal centre line on the rear wall. Extend the horizontal centre line to the side wall and mark the vertical centre line of the flue hole as shown in diagram 12. Important: When cutting the flue hole and when extending the flue centre line to a side wall, remember that the flue system must have a fall of about 35 mm per metre of flue DOWNWARD AWAY FROM the boiler. There must NEVER be a downward incline towards the boiler. Cutting the flue hole Making allowance for the slope of the flue, cut hole in external wall, preferably using a core drill. For installations with internal and external access Use a 105 mm diameter core drill. For installations with internal access only - Use a 125 mm diameter core drill. Important: Before cutting the hole for flues to the rear of boiler, always cover fixing jig to make sure it is not damaged. Calculation of flue cutting lengths Measure wall thickness e (mm). For side flues, measure distance from inside face of side wall to centre line of flue and subtract 176 mm for right hand flue or subtract 234 for left hand flue to get dimension a (mm), see diagram 13 or 14. Refer to table 1 for cutting lengths of both inner and outer flue pipes for each of the various flue options available. Important: All flue cutting lengths must be measured from the terminal end of the flue pipes, see diagram 15. When the dimension X measured on site is greater than that given in table 1, a flue extension kit will be required, refer to table 2 for details. Refer to table 1 for the cutting lengths of both the inner and outer pipes for each of the flue options available.

Diagram 12

Diagram 13
Table 1 Flue cutting lengths

Diagram 15

Outer pipe

Cutting length

Inner pipe

Ven 089

Table 2 Number of extension kits required
Flue option Side flue (left or right) Dimension 'X' 1081 to 1811mm 1812 to 2542 mm No. of extension kits 1 2
Table 3 Extended flue cutting lengths
Cutting length (mm) Flue option Rear outlet Side flue to left (Diagram 13) outer pipe e + a - 906 inner pipe e + a + 829 Comments maximum distance 'X' without extension 1080 mm maximum distance 'x' without extension 1080 mm
Rear outlet Side flue to right (Diagram 14)

e + a - 848

e + a + 771

Diagram 16

Pho 087
TOP OUTLET FLUE INSTALLATION
Top outlet flue - kit 86151 see diagram 18, is 1000 mm long and comprises: - Outer pipe... A - Inner pipe.. B - External rubber sealing collar.. C - Flue elbow... D - Internal flange... E - 'O' rings.... F - Screws... G - Rubber collar... H - Clamp and seal... I - Gasket... J A - Flue to rear of boiler Mark correct position of hole from template. B - Flue to side of boiler Mark horizontal centre line for hole on rear wall. Extend horizontal centre line to side wall and mark vertical centre line of flue hole as shown in diag. 12. Under normal circumstances, it will be possible to gain access to the outside of the building to fit the flue terminal assembly. Where outside access is not possible e.g. high rise buildings, the flue terminal can be fitted from inside the building only if required. Note : When cutting flue hole and when extending flue centre line to a side wall, remember that the flue system must have a fall of about 35 mm per metre of flue DOWNWARD AWAY FROM the boiler. There must NEVER be a downward incline towards the boiler. Cutting the flue hole Making allowance for the slope of the flue, cut hole in external wall, preferably using a core drill. For installations with internal and external access - Use a 105 mm diameter core drill. For installations with internal access only - Use a 125 mm diameter core drill. Important: Before cutting hole for flues to rear of boiler, always cover fixing jig to make sure it is not damaged.

Table 1 :

Flue Cutting length (mm) Flue option outer pipe inner pipe e + a + 202 Comments maximum distance 'X' without extension 1080 mm Flue option outer pipe inner pipe e + a + 800 Comments maximum distance 'X' without extension 1080 mm Top outlet e + a + 877 Side flue to (left or right)

Diagram 17

Diagram 18
Table 2 : Number of extension kits required Flue option Dimension 'X'
Side flue (left or right) 1081 to 1811 mm 1812 to 2542 mm No. of extension kits 1 2

Table 3 :

Extended Flue Cutting length (mm)
Top outlet e + a + 125 Side flue to (left or right)
Calculation of flue cutting lengths Measure wall thickness e (mm), see diagram 17. For side flues, measure distance from inside face of side wall to centre line of flue and subtract 205 mm for both right and left hand flues to get dimension a (mm). Refer to table 1 for cutting lengths of both inner and outer flue pipes for each of the various flue options available. Important: All flue cutting lengths must be measured from the terminal end of the flue pipes, see diag. 15. When the dimension X measured on site is greater than that given in table 1, a flue extension kit will be required, refer to table 2 for details. Extended flue The horizontal flue is extended by using one or more of the 1000 mm extension pipes, Saunier Duval part number 85091. These are connected together by push fit type joints, clamps and seals. Calculation of flue cutting lengths for extended flue Using the correct number of extension kits as table 3, measure dimensions a and e, see diagram 17. Important: All cutting lengths should be measured from the push fit end of the extension pipe. Do not leave any burrs or sharp edges on the cut ends of the pipes.
Installation of flue assembly Fit rubber sealing collar (C) into groove at the outer end of pipe (A), see diagram 18. Fit outer pipe (A) into wall with the groove to the outside. Pull pipe inwards to bring rubber sealing collar hard up against external wall, see diagram16. Fit internal plastic flange (E) onto outer pipe. Push along the pipe until engaged against internal wall. From inside, insert inner pipe (B) into outer pipe. Fit both 'O' rings (F) into the flue elbow (D), one at the inlet, one at the outlet. By necessity, they are a loose fit, apply a small amount of silicone grease to each 'O' ring when fitting. Important: If the flue has been cut, ensure that there are no burrs that could damage the 'O' ring. Remove the backing from the self adhesive gasket (J) and carefully fit gasket to base of flue elbow. Fit elbow onto boiler and secure with the four screws (G). Take hold of inner flue, twist clockwise and push gently onto the elbow outlet taking care not to tear the 'O' ring. Fit clamp and seal (I) onto outer pipe ensuring a good seal.

Hab 210b

ELECTRICAL CONNECTION
Warning. This boiler must be earthed All system components must be of an approved type. The mains electrical cable is supplied with the boiler. It is coiled ans tucked inside the boiler Connection of the whole electrical system and any heating system controls to the electrical supply must be through a common isolator. Isolation should preferably be by a double pole switched fused spur box having a minimum contact separation of 3 mm on each pole. The fused spur box should be readily accessible and preferably adjacent to the boiler. It should be identified as to its use. A fused three pin plug and shuttered socket outlet may be used instead of a fused spur box provided that: a) They are not used in a room containing a fixed bath or shower. b) Both the plug and socket comply with the current issue of BS1363. The mains electrical supply must be maintained at all times in order to provide domestic hot water. Do not interrupt the mains supply with a time switch or programmer. WARNING: ON NO ACCOUNT MUST ANY EXTERNAL VOLTAGE BE APPLIED TO ANY OF THE TERMINALS ON THE HEATING CONTROLS CONNECTION PLUG. Warning: This appliance must be wired in accordance with these instructions. Any fault arising from incorrect wiring cannot be put right under the terms of the Saunier Duval guarantee. Time clock A mechanical or digital time clock is available as an accessory, Saunier Duval part N 86148 (mechanical) or 86149 (digital). External controls The THEMA boiler is designed to operate at maximum efficiency at all times. The of a programmable electronic room thermostat is recommended for optimum performance, Saunier Duval part number 40010. Please contact your supplier. The boiler will work for heating without a room thermostat and/or timeswitch being connected provided that the wire link fitted between the two terminals of the connector (E) is left in place, see diagram 19. A 230V room thermostat can be used but do not make any connection to the compensating resistor, see diagram 19. ON NO ACCOUNT must any electrical voltage be applied to any of the terminals of the external controls plug.
When fitting room thermostat, remove wire link (E) and connect voltage free thermostat as shown
For no external controls leave wire link (E) in place

sch 228

The mains electrical cable is supplied with the boiler. It is coiled and tucked inside the boiler

Cylinder

THEMA F SB 18 E THEMA F SB 23 E

Diagram 19

sch 227

sch 229

COMMISSIONING

Ins 061

Ins 062

Bleed air from the heat exchanger by undoing the air bleed cap. Do not remove this cap. When all the air has been removed, tighten cap.
Bleed each radia tor until a continuous jet of water is obtained.
Open various hot water taps to bleed system.
Make sure that pressure gauge reads between 1 and 2 bar. Re-pressurise system as necessary.

Reg 008

mec 117
On reaching maximum temperature, the boiler should be turned off and the system drained as rapidly as possible whilst still hot. Refill system to a pressure of 1 bar and vent as before. Restart boiler and operate until a maximum temperature is reached. Shut down boiler and vent heating system. If necessary, top up heating system and make sure that a pressure of 1 bar is indicated on the pressure gauge when system is COLD. Gas pressures The main burner pressure should be checked during commissioning to make sure the correct input is obtained. Proceed as follows: Shut down boiler. Undo screw on burner pressure test point below sealed combustion chamber, see diagram 23. Connect a suitable pressure gauge. Gain access to the rear of the control panel and locate the range rating adjuster screw, see diagram 24. Start boiler as described in 'User Instructions'. Set boiler thermostat to maximum and check that any external controls are calling for heat. Check that the reading on the gauge matches that given in 'Technical Data' for the type of gas being used. Adjust the range rating adjuster screw as necessary to obtain the desired input. Shut down boiler. Remove pressure gauge, tighten up test point screws and check for gas soundness. Using a ball point pen, clearly indicate on the data label the input the boiler is set to. Note: This adjustment does not affect the domestic hot water output. If measured burner pressure differs greatly from the given figure, check the gas inlet pressure as follows: Shut down boiler.

Diagram 23

Diagram 24
Remove screw from inlet test point on the side of the gas valve, see diagram 23. Connect a suitable pressure gauge. Start boiler as described in 'User Instructions'. Check that the inlet pressure reading matches that given in 'Technical Data' for the type of gas being used. Shut down boiler. Remove pressure gauge, tighten up test point screws and check for gas soundness. If the gas pressure is incorrect, refer to the Fault Finding section in 'Servicing Instructions'. If the inlet pressure is below that given, the gas supply pipework/meter must be checked and any fault corrected. In the case of an LPG installation, check the storage tank or cylinder, regulator and pipework.

Diagram. 27

Reg 055 Mec 121

Diagram. 26

ON DIP

CHANGING GAS TYPE

Should it become necessary to change the gas type, a modification kit will be required. This modification must only be carried out by a suitably qualified engineer. Conversion: Natural Gas (G20) to G30/G31 Part No. 86161

Reg 013

ROUTINE CLEANING AND INSPECTION
To ensure the continued efficient and safe operation of the boiler it is recommended that it is checked and serviced at regular intervals. The frequency of servicing will depend upon the particular installation conditions and usage, but in general once a year should be enough. It is the law that any servicing is carried out by a competent person. Service Check and Preparation. Operate boiler and check for any faults that need to be put right. Isolate boiler from the gas and electrical supplies. On completion check all gas carrying parts for soundness with leak detection fluid. The maximum domestic hot water flow rate is 12 litres/minute. Remove boiler casing as follows: Upper front panel Hinge down control cover to gain access to control panel. Disengage the two 'quarter turn' fasteners by turning the heads of the screws a quarter of a turn towards the centre of the boiler. Carefully lower the panel down on its hinge until it is horizontal. Turn both plastic catches to release upper front panel. Remove upper front panel by pulling forward at the bottom and lifting off. Note: The upper front panel is retained by a plastic safety strap, disengage this before removal. Side panels From below boiler, unscrew and remove black plastic screws securing side panels to the boiler. Prise out black plastic inserts and lift panel off boiler. Combustion chamber Loosen two wing nuts on combustion chamber cover. Disengage retaining lugs from holes in either side of combustion chamber and move rods away to clear combustion chamber sides, see diagram 28. Unclip two toggle clips holding upper part of combustion chamber in place. Holding both sides, pull chamber forward to release it from underside of heat exchanger and out of boiler. Take care not to damage insulation material on inside faces of combustion chamber. Cleaning the burner Pull off leads to ignition electrode. Pull off lead to flame sense electrode. Unscrew and remove screw holding earth lead to flame sense electrode. Undo main gas supply nut from main burner. Unscrew and remove locking nut from both main gas connection and burner pressure tapping point. Lift front edge of burner until tapping point and gas supply connection are free. Remove burner

Diagram 28

from boiler taking care to retain both fibre washers and seal on gas supply for use on reassembly. Unscrew and remove two injector bar retaining screws and separate injector bar from burner. Examine and clean injectors as necessary. Note: Do not use a wire or sharp instrument on the holes. Replace burner in reverse order to removal. Heat exchanger After removal of burner, examine heat exchanger for any blockages or build up of deposits. Clean using soft brush or vacuum cleaner. Important: Take care not to scratch or otherwise damage painted surface of heat exchanger. Reassembly of parts removed for servicing Replace all parts in reverse order to removal. Flue system Check externally to make sure flue is not blocked. Inspect flue system to make sure all fittings are secure. Operation of fan Switch on electrical supply and turn on gas. Switch boiler On/Off switch to 1 (On). Light burner by opening a hot tap. Without upper front panel in place, burner should be prevented from lighting by air flow detection system. Refit upper front panel. Check that fan runs when burner is lit and stops when it goes out. Cold water inlet filter (exept SB models) Drain down hot water circuit of boiler as follows: Close isolating valve on cold water inlet connection on fixing jig, see diagram 5. Open one or more hot water taps to drain boiler. Undo connecting nut from cold water inlet connection to gain access to filter. Remove white filter from inlet connection.

Des 047

Note: Connecting pipework is telescopic, it may be necessary to slide sleeve back for easier access to filter. Clean and inspect filter, replace if necessary. With both flow restrictor and filter in place, reconnect pipe to inlet connection and tighten. Fully open isolating cock on cold water inlet connection and check for leaks. Operation of water valve (exept SB models) With the Summer/Winter control in the 'Summer' position, slowly open a convenient tap until boiler lights. Measure water flow, it should not be greater than 3,5 litres/minute. If necessary, replace diaphragm. Replace all outer panels.

REPLACEMENT OF PARTS

To replace microswitch assembly exept SB models) Disconnect microswitch by pulling off plug. Unclip external controls connector from mounting bracket. Undo two screws securing microswitch assembly to reversing valve assembly, see diagram 29. Remove microswitch assembly from reversing valve. Fit replacement microswitch assembly in reverse order to removal. Reconnect plug and refit external controls connection to bracket. To replace fan Disconnect power supply and earth leads to fan. Unscrew and remove two fan retaining screws located at front edge of fan mounting plate. Remove fan with mounting plate attached by pulling forwards and out of boiler. Unscrew and remove three screws securing fan to fan mounting plate. Fit replacement fan to mounting plate and secure with screws. Fit replacement fan to boiler in reverse order to removal making sure that mounting plate retaining lugs are properly engaged into flue hood. Reconnect power supply and earth leads. Important: Make sure that fan outlet is correctly fitted into either the flue elbow for top outlet flue, or the rear connector for rear outlet flue. Before commissioning boiler, remove the two plastic transit clips from replacement fan. To replace air pressure switch Locate air pressure switch in upper left hand corner of sealed chamber. Pull off plastic tube from left hand connection. Grasp pressure switch and disengage it from bracket clips by pulling from the top. Remove electrical connections from switch. Fit electrical connections to terminals 1 and 3 of replacement switch. Fit replacement switch in reverse order to removal. Important: Refit plastic tube to LEFT hand connector (marked P1). To replace spark generator Locate spark generator on bracket to right hand side of gas valve. Undo and remove screw securing lower terminal cover to bracket and remove bracket. Disconnect four leads from spark generator.

Diagram 31

Diagram 32
Fit capillary of new gauge to front section using new 'O' ring supplied. Open isolating valves on flow and return connections, refill, vent and pressurise boiler. Check for leaks. To replace reversing valve assembly Remove temperature/pressure gauge capillary as described previously. Remove pump as described previously. Remove microswitch assembly as described previously. Remove retaining clip from LHS pipe connection on front section of valve and disengage pipe. Unscrew and disconnect heating flow (centre) connection at fixing jig. Remove retaining clip from heating flow pipe connection on right of front section. Remove flow pipe from boiler. Unscrew and disconnect heating return (left hand) connection at fixing jig. Remove retaining clip from expansion vessel pipe connection at rear of reversing valve assembly and disengage pipe, pushing pipe back and out of reversing valve. Undo and remove large screw holding water valve to back plate of reversing valve assembly, see diagram 32.

Des 054

Cla 007
Push water valve back to disengage it from reversing valve. Unclip and remove loss of water pressure switch from left of reversing valve assembly, see diagram 33. From below boiler, undo and remove three screws holding reversing valve to bottom plate of boiler. Remove complete reversing valve assembly from boiler. Undo and remove heating return connecting pipe and hose from rear of reversing valve assembly. Fit hose to replacement reversing valve assembly. Fit replacement reversing valve into boiler in reverse order to removal. Note: Use new 'O' rings, retaining clip, filter and washer provided. Unscrew and remove microswitch assembly from top of replacement reversing valve assembly to allow refitting of water valve. Note: fit expansion vessel pipe and loss of water switch to reversing valve assembly before pump, to ensure that it is correctly located. Apply silicone grease to all 'O' rings and hoses prior to assembly. Open isolating valves on flow and return connections, refill, vent and pressurise boiler. Check for leaks. To replace reversing valve front section Remove pressure gauge capillary as described previously. Remove pipe connections from either side of reversing valve front section, refer to previous section. Move short selector lever on front of valve to left hand position. From below boiler, undo and remove single screw holding reversing valve front plate to bottom plate of boiler. Undo and remove six screws holding front section to rear section of reversing valve, see diagram 34. Remove front plate complete with pump bracket and then front section from reversing valve, along with rubber sealing gasket. Assemble bypass valve provided and fit into hole in underside of replacement front section. Fit 'U' shaped retaining clip. Note: Use bypass valve fitted to original front section for guidance. Fit replacement front section, with gasket, to rear section. Locate front plate and replace six fixing screws. Take care to evenly tighten screws ensuring they are not cross threaded. Refit pipe connections to either side of front section using new 'O' rings provided. Apply silicone grease to 'O' rings before fitting. Refit pressure gauge capillary in reverse order to removal. Ensure short selector lever on front of valve is set to right hand position. Open isolating valves on flow and return connections, refill, vent and pressurise boiler. Check for leaks.

Diagram 33

Diagram 34
To replace loss of water switch Drain down heating circuit of boiler only as described in 'To replace pump'. Note: It is not necessary to drain entire heating circuit to carry out this work. Pinch plastic cover to release retaing clips and remove cover from switch. Pull plug lead from switch terminals. Remove clip holding switch into left side of reversing valve assembly. Pull switch out of reversing valve assembly, see diagram 33. Fit replacement switch in reverse order to removal, using new 'O' ring provided and applying silicone grease to 'O' ring before fitting. Reconnect plug to switch terminals. Open isolating valves on flow and return connections, refill, vent and pressurise boiler. Check for leaks. To replace water valve or diaphragm (except SB models) Drain down hot water circuit of boiler only as described in 'Routine Cleaning and Inspection'. Remove microswitch assembly as described previously. Unscrew connecting nut from cold water inlet connection, second from left on fixing jig. Keep filter and flow regulator. Remove clip holding connecting pipe in rear of water valve. From below boiler, grip clip with long nosed pliers and pull down. Note: This connecting pipe is telescopic, it may be necessary to slide back brass sleeve to facilitate removal.

Sec 059

Remove clip holding pipe to heat exchanger in rear of water valve. From front of boiler, grip clip with long nosed pliers and pull upwards. Unscrew and remove large screw holding water valve to back plate of reversing valve assembly, see diagram 32. Disengage water valve from reversing valve and remove from boiler. Note: When disengaging water valve from heat exchanger pipe, check that non-return valve is not held on end of pipe. If so, carefully separate pipe from valve to ensure that small spring and plunger do not fly out and are lost. To replace diaphragm, undo five screws and separate main components of water valve. If white diaphragm cover is to be replaced, separate original from water valve end casting and fit replacement cover. Fit replacement diaphragm , making sure that metal disc FACES diaphragm cover and beaded edge of diaphragm is correctly fitted in corresponding groove in both cover and plastic housing, see diagram 35. Reassemble water valve, evenly tightening five screws. Fit water valve actuating pin into hole in diaphragm cover, through nose end of valve and and push in until flush, or slightly below, nose end of valve. Note: Apply silicone grease to pin before fitting. Refit water valve to boiler, locating nose end into rear of reversing valve assembly, 'springing' heat exchanger pipe to gain clearance as necessary. Fit large water valve retaining screw but do not tighten fully at this stage. Apply silicone grease to 'O' ring and fit onto end of heat exchanger pipe. Fit pipe into water valve by pulling it forward. Make sure that 'O' ring is correctly located. Whilst holding pipe in rear of water valve, fit retaining clip. This should easily clip over pipe and should NOT have to be forced. If resistance is experienced, either pipe is not correctly fitted in rear of water valve or clip is not being fitted properly through slot between back plate and plastic housing of water valve. When clip is fitted, check connection by pushing pipe back away from water valve. Refit telescopic connecting pipe to inlet of water valve after applying silicone grease to 'O' ring. Fit retaining clip into groove on connecting pipe, through slot between back plate and water valve plastic housing. Check connection by pulling pipe. Make sure that clip is not loose and likely to fall out at a later date. If in doubt, fit a new clip. With both flow regulator and and plastic filter washer in place, refit connecting nut to inlet connection and tighten. Open isolating valve on cold water inlet connection and check for leaks. Replace microswitch assembly. To replace gas valve Ensure gas supply is off. Disconnect two black electrical leads from gas valve modulating coil.

Diagram 35

Diagram 36
Disconnect two white and one red lead from gas valve main solenoid. Pull off clear plastic tube from gas valve to sealed chamber tapping point. Unscrew main gas supply pipe nut on top of gas valve, releasing spark ignition unit bracket, see diagram 36. From below boiler, unscrew gas valve connection between gas valve and fixing jig isolating cock. Unscrew and remove two screws securing gas valve to bottom plate of boiler. Remove gas valve from boiler. Refit replacement gas valve in reverse order to removal. Note: Use new 'O' ring provided between gas valve and burner supply pipe. Refit electrical connections to replacement gas valve as follows: - BLACK leads to modulating coil. - WHITE leads to EV1 and EV2 terminals of main solenoid - RED lead to COM terminal of main solenoid. To replace modulating coil Ensure gas supply is off. Disconnect two black electrical leads from gas valve modulating coil. Unscrew and remove two screws holding modulating coil to gas valve and remove coil from gas valve. Fit replacement modulating coil in recerse order to removal. Reconnect electrical leads to replacement coil. Note: All boilers are tested and factory set during manufacture. Should it be necessary to reset a gas valve, for example after replacement, refer to 'Settings'.

Mec 117

Des 058
To replace safety valve Drain down entire heating system. From below boiler, disconnect heating flow pipe from rear of fixing jig. Undo heating flow connection on front of fixing jig. Remove clip from heating flow pipe connection on right of front section of reversing valve. Pull pipe towards right and out of reversing valve. Remove pipe from boiler and keep. From below boiler, disconnect safety valve discharge pipe. Working through boiler from the front using a long screwdriver, undo and remove screw holding safety valve assembly to fixing jig. Remove complete safety valve assembly from fixing jig and remove from boiler. Fit replacement safety valve in reverse order to removal. Note: Apply silicone grease to 'O' ring before fixing pipe into right hand side of reversing valve. Refill heating system and boiler, vent and pressurise as described previously. To replace heat exchanger Drain down both heating and hot water circuits of boiler only as described previously. Note: It is not necessary to drain entire heating system to carry out this work. Remove combustion chamber cover as described in 'Routine Cleaning and Inspection'. Remove two clips from heating connections to left side of heat exchanger. Remove clip holding pump outlet connection into pump and slide connection up pump outlet pipe. Pull complete pipe down to disengage from heat exchanger. Remove retaining clip from LHS pipe connection on front section of valve and disengage pipe. Disengage pipe downwards from heat exchanger. Unscrew and disconnect two hot water connections to right side of heat exchanger. Grasp both sides of heat exchanger and slide forwards and out of boiler. Fit replacement heat exchanger in reverse order to removal. Note: Use new sealing washers and 'O' rings provided. Open isolating valves on flow and return connections, refill, vent and pressurise boiler. Check for leaks. To replace expansion vessel 1 Boiler in place Note: The expansion vessel can be replaced with the boiler in place provided that there is a minimum clearance of 400mm on one side of the boiler and that no vertical pipework passes between boiler and wall on that side. Drain down the heating circuit of the boiler only as described in 'To replace pump'. Note: It is not necessary to drain entire heating system to carry out this work. Remove pump from boiler as described previously. Unscrew pipe connection nut from expansion vessel and disengage pipe from connection. Keep sealing washer. Whilst supporting weight of vessel, push bottom of vessel away from boiler, disengaging threaded connection from hole in rear of boiler. Allow vessel to drop out of its two upper retaining brackets. Remove vessel to side of boiler. Fit replacement expansion vessel in reverse order to removal ensuring that sealing washer is fitted to vessel pipe connection. Check that vessel charge pressure is 1bar. Correct if necessary. Open isolating valves on flow and return connections, refill, vent and pressurise boiler. Check for leaks. 2 Boiler removed from wall Drain down the heating circuit of the boiler only as described in 'To replace pump'. Note: It is not necessary to drain entire heating system to carry out this work. Ensure that gas and electrical supplies to boiler are turned off. Disconnect flue from either rear or top of boiler as applicable. Disconnect external controls connections, if applicable. Unscrew and disconnect five connections between fixing jig and boiler. Disengage pipe connections. Lift boiler off hanging bracket and place on a convenient working surface. Remove expansion vessel from boiler as described in previous section. Fit replacement vessel in reverse order to removal and check charge pressure. Replace boiler on wall, tighten all connections, gas connection first, ensuring that all sealing washers, filters and the cold water flow regulator are fitted before tightening. Reconnect flue system. Open isolating valves on flow and return connections, refill, vent and pressurise boiler. Check for leaks. Reconnect external controls connections, if applicable. Reconnect gas and electrical supplies to boiler. Check for gas soundness. To replace boiler thermistor Locate boiler thermistor on heating flow pipe on left hand side of boiler, see diagram 37.

Accessories

A range of accessories are available. For further information contact your supplier.

Appliance Safety Devices

Air flow rate safety device
If the flue is obstructed, the built in safety system will turn the boiler OFF, the fan will continue to run. The boiler will be ready to operate when the fault has been cleared.

Frost protection

The appliance has a built in frost protection device that protects the boiler from freezing. With the gas and electric supplies ON and irrespective of any room thermostat setting, the frost protection device will light the boiler when the temperature of the boiler water falls below 6C. When the temperature reaches 16C, the boiler stops. Any other exposed areas of the system should be protected by a separate frost thermostat.

Overheating safety

In the event of the boiler overheating the safety devices will cause a safety shutdown. If this happens, call your Installation/ Servicing company.
Electrical supply failure
The boiler will not operate without an electrical supply. Normal operation of the boiler should resume when the electrical supply is restored. Reset any central heating system controls, to resume normal operation. If the boiler does not resume normal operation turn the mains reset switch off and on. If the boiler does not resume normal operation it is advisable to consult your installation / servicing company.

Heating safety valve

CAUTION: A heating safety valve with a discharge pipe is fitted to this boiler. The valve MUST NOT BE TOUCHED except by a competant person. If the valve discharges at any time, switch the boiler off and isolate it from the electrical supply. Contact your installation/ service company.
Maintenance and Servicing

Cleaning

WARNING: This appliance contains metal parts (components) and care should be taken when handling and cleaning with particular regard to edges of sheet metal parts to avoid any possibility of personal injury. The boiler casing can be cleaned with a damp cloth, followed by a dry cloth to polish. Do not use abrasive or solvent cleaners. Please be advised that the Benchmark logbook should be completed by the engineer on completion of commissioning and servicing. All CORGI Registered Installers carry a CORGI ID card, and have a registration number. Both should be recorded in your benchmark Logbook. You can check your installer is CORGI registered by calling CORGI direct on: (0) 1256 372300.

Burner injector Inlet pressure Maxi. Burner pressure Mini. Burner pressure Gas rate maximum Gas rate minimum 1,2 mm 20 mbar 12,2 mbar 2,25 mbar 2,74 m3/h 1,16 m3/h

Butane Gas (G30)

Burner injector Inlet pressure Maxi. Burner pressure Mini. Burner pressure Gas rate maximum Gas rate minimum 0,73 mm 29 mbar 17,65 mbar 4,41 mbar 1,72 kg/h 0,87 kg/h
Burner injector Inlet pressure Maxi. Burner pressure Mini. Burner pressure Gas rate maximum Gas rate minimum 0,73 mm 29 mbar 23,2 mbar 4,41 mbar 2,01 kg/h 0,87 kg/h

Propane Gas (G31)

Burner injector Inlet pressure Maxi. Burner pressure Mini. Burner pressure Gas rate maximum Gas rate minimum 0,73 mm 37 mbar 22,52mbar 5,4 mbar 1,70 kg/h 0,83 kg/h
Burner injector Inlet pressure Maxi. Burner pressure Mini. Burner pressure Gas rate maximum Gas rate minimum 0,73 mm 37 mbar 29,8 mbar 5,4 mbar 2,01 kg/h 0,83 kg/h

1 Technical Data

The F24E and F18E SB are delivered in two separate packages: The boiler including hanging bracket complete with isolating valves and fittings. The flue system.
Net lift weight (boiler only) F24E 34 kg F18E SB 32 kg Gross lift weight (boiler, hanging bracket isolation valves and packaging) F24E 35 kg F18E SB 33 kg

Diagram 1.1

2 General Information
IMPORTANT NOTICE. Where no British Standards exists, materials and equipment should be fit for their purpose and of suitable quality and workmanship. Refer to Manual Handling Operations, 1992 regulations. The installation of this boiler must be carried out by a competent person in accordance with the rules in force in the countries of destination. Manufacturers instructions must not be taken as overriding statutory requirements. 2.1 Sheet Metal Parts WARNING: When installing the appliance, care should be taken to avoid any possibility of personal injury when handling sheet metal parts. 2.2 Statutory Requirements The appliance is suitable only for installation in GB and IE and should be installed in accordance with the rules in force. In GB the installation of the boiler MUST be carried out by a competent person as discribed in the following regulations: Manufacturers instructions, supplied. The Gas Safety (Installation and Use) Regulations. The appropriate Building Regulations, either The Building Regulations, The Building Regulations (Scotland), The building Regulations (Nothern Ireland). The Water Fittings Regulations or Water Bylaws in Scotland. The Health and Safety at Work Act, Control of Substances Hazardous to Health (COSHH). The Current I.E.E. Wiring Regulations. Where no specific instructions are given, reference should be made to the relevant British Standard Code of Practice. In I.E the installation must be carried out by a competent person and installed in accordance with the current edition of I.S. 813 "Domestic Gas Installations", the current Building Regulations and reference should be made to the current ETCI rules for electrical installation. In GB the following Codes of Practice apply: BS4814, BS5440 Part 1 and 2, BS5449, BS5546 Part 1, BS6700, BS6798, BS6891 and BS7074 Part 1 and 2, BS7478, BS7593, BS7671. In IE: I.S.813, BS5546, BS5449, BS7074, BS7593. Manufacturers notes must not be taken as overriding statutory requirements. BSI Certification This boiler certificated to the current issue of EN 483 for performance and safety. It is important that no alteration is made to the boiler, without permission, in writing, from Hepworth Heating Ltd. Any alteration that is not approved by Hepworth Heating Ltd., could invalidate the warranty and could also infringe the current issue of the Statutory Requirements.

2.3 Gas Supply The gas installation must be in accordance with the relevant standards. In GB this is BS 6891. In IE this is the current edition of I.S.813 "Domestic gas installation". The supply from the governed meter must be of adequate size to provide a steady inlet working pressure of 20mbar (8in wg) at the boiler. Important Notice If your boiler has been converted to use L.P.G. Propane the following note applies: Propane cylinders are under pressure and should never be stored or used indoors residentially. They should only be kept outside. Under no circumstances should L.P.G. Propane cylinders be fitted or stored in basement areas or boiler houses. On completion, test the gas installation for soundness using the pressure drop method and suitable leak detection fluid, purge in accordance with the above standard.

3 Heating System Design

Bypass fully shut

Available pressure (kPa)

Open 1/4 turn Open 1/2 turn Open 1 turn Open 2 turns

(10 kPa = 1 m WG)

Flow rate through heating system (I/h)

Diagram 3.1

The installation of the boiler must comply with the requirements of the current issue of BS6798, in Ireland, refer also to the current edition of I.S.813"Domestic Gas Installations". In GB it is necessary to comply with the Water Supply (Water Fittings) Regulations 1999 (for Scotland, the Water Byelaws 2000, Scotland). To comply with the Water Regulations your attention is drawn to: The Water Regulations guide published by the Water Regulation Advisory Service (WRAS) which gives full details of the requirements. In IE the requirements given in the current edition of I.S.813 "Domestic Gas Installations" and the current Building Regulations must be followed. The F24E and F18E SB are for use with sealed central heating systems. Heating surfaces may consist of radiators, convectors or fan assisted convectors. The safety valve is an integral part of the boiler and it cannot be adjusted. The circulation pump is integral with the boiler. Pipe sectional areas shall be determined in accordance with normal practices, using the output/pressure curve (diagram 3.1). The distribution system shall be calculated in accordance with the output requirements of the actual system, not the maximum output of the boiler. However, provision shall be made to ensure sufficient flow so that the temperature difference between the flow and return pipes be less than or equal to 20C. The minimum flow rate is shown in table 1. 13
The system can be fitted with a lockable control valve if necessary in the main flow or return pipes shown as valve 'A' in diagram 3.2. The piping system shall be routed so as to avoid any air pockets and facilitate permanent venting of the installation. Bleed fittings must be provided at every high point of the system and on all radiators. The total volume of water permitted for the heating system depends, amongst other things, on the static head in the cold condition. The expansion vessel on the boiler is pressurised at 0.5 bar and allows a maximum system volume of 110 litres for an average temperature of 75C and a maximum service pressure of 3 bar. This pressure setting can be modified at commissioning stage if the static head differs. An additional expansion vessel can be fitted to the system if required, see diagram 3.2. Guidance on vessel sizing is also given in a current issue of a BS5449 and BS7074 Part 1, for IE refer to the current edition of I.S.813 "Domestic Gas Installations". Provision shall be made for a drain valve at the lowest point of the system. Where thermostatic radiator valves are fitted, not all radiators must be fitted with this type of valve, and in particular, where a room thermostat is installed. In the case of an existing installation, it is ESSENTIAL that the system is thoroughly flushed prior to installing the new boiler, using a proprietary product from Fernox or Sentinel.

3.1 Bypass

The boiler is fitted with an adjustable automatic bypass. Ensure that under no circumstances does the flow rate drop below the figure specified, see table 1. A system bypass is not required on the central heating circuit unless the system controls will not ensure aminimum water flow rate. Where a bypass has to be fitted, the bypass must be placed at least 1.5 metres away from the appliance, see diagram 3.2.
3.3 Filling the system F18E SB.
Provision for filling the system must be made. The methods are shown in diagram 3.3. There must be no permanent connection to the mains water supply, even through a nonreturn valve. NOTE: It is important that fittings used for connection to potable water comply with the water undertakings requirements.
TABLE 1. FLOW RATE Model F24E F18E SB Minimum flow rate 16.94 litres per minute 13.21 litres per minute
3.2 Filling the system F24E.
An integral filling device is fitted to the boiler to initially fill the system and replace water lost during servicing, see the relevant parts of diagram 2 controls and lighting and diagram 1.
This is equal to 20C differential at maximum heat input.
SUPPLY PIPE BOILER CONTROL VALVE DOUBLE CHECK VALVE HOSE UNION

Boiler

Domestic water
Cold supply in Hot water out

Filling device

Additional expansion vessel (if required)

RETURN

Drain point Control valve Drain point

Bypass valve

Return
Additional Bypass valve (if required)

HEATING CIRCUIT

TEMPORARY CONTROL HOSE CONNECTION VALVE UNION DRAIN POINT

Heating circuit

Method 1

BOILER

TYPE CA BACKFLOW PREVENTION DEVICE FLOW RETURN CONTROL VALVE CONTROL VALVE SUPPLY PIPE AIR GAP
Bypass valve Control valve Drain point

DRAIN POINT Method 2

TUNDISH

Diagram 3.2

Diagram 3.3
4 Domestic Hot Water System Design. F24E Only
General - All domestic hot water circuits, connections, fittings must be in accordance with the relevant standards and water supply regulations. For GB: Guidance G17 to G24 and recommendation R17 to R24 of the Water Regulation Guide. For IE: The current edition of I.S.813 "Domestic Gas Installations". Copper tubing or plastic Hep20 may be used for the domestic hot water system. Unnecessary pressure losses should be avoided. Provision shall be made for a drain valve at the lowest points of the system. The flow restrictor, supplied in the document envelope, must be fitted as diagram 7.1, limiting the flow through the boiler to a maximum of 10 litres/min. The boiler will operate with a minimum supply pressure of 0.5 bar, at a reduced flow rate. Best operating performance will be obtained from a supply pressure of 1 bar or greater.

8.2 Fixing jig, refer to diagram 7.1
IMPORTANT NOTE: Ensure that the hanging bracket is fitted to a flat and true wall area for correct alignment with the boiler. Side Flue - Check the horizontal centre line and reposition the template if necessary. Rear Flue - Reposition the wall template over the hole in wall. Mark the securing position holes. Check that the hanging bracket is level. Drill, plug and secure the bracket to the wall, using suitable screws (not supplied) for the wall type and capable of supporting the total weight of the appliance (refer to wall template for fixing points).

Diagram 8.1

8.3 Water connection
IMPORTANT NOTE: Do not subject the isolating valves to heat from blowlamp, when making connection. Connect the system pipework to the fixing jig connection pipes and the fixing jig isolating valves, observing the correct flow and return as shown in diagram 8.1.
8.4 Gas connection Gas Safety (Installation and use) Regulations
In your interests and that of gas safety, it is the law that ALL gas appliances are installed and serviced by a competent person in accordance with the above regulations. The whole of the gas installation, including the meter, should be inpected, tested for soundness and purged in accordance with the current issue of BS6891 and in IE the current edition of I.S.813 "Domestic Gas Installations".

9 Boiler Installation

9.1 Sheet metal parts
WARNING: When installing or servicing this boiler, care should be taken when handling the edges of sheet metal parts to avoid the possibility of personal injury. If fitted ensure the plastic plugs are removed from water and gas pipes. NOTE: There will be some spillage of water. (F24E Only) Fit the cold water inlet restrictor (supplied in the document envelope) into cold water inlet isolating valve, see diagram 7.1. Important Note. With regards to the manual handling operations, 1992 regulations, the following operation exceeds the recommended weight for one man lift. Lift the boiler up and engage boiler onto the hanging bracket, refer to diagram 7.1. Fit the boiler connection pipes and washers between the boiler and isolating valves, see diagram 7.1.
9.2 Installing the boiler
IMPORTANT NOTE: The system must be thoroughly flushed using a propriety cleanser from Fernox or Sentinel to eliminate any foreign matter and contamination e.g. metal filings, solder particles, oil, grease etc. Solvent products could cause damage to the system. Remove front panel, unscrew and remove the two retaining screws from the bottom of the front panel. Remove front panel by lifting up and forward. To remove the self adhesive wiring diagram label from the document envelope. Fit the self adhesive wiring diagram label to the inside of the front panel, put front panel in a safe place to avoid damaging it.

9.3 Discharge safety valve (diagram 9.1)
The discharge safety valve pipe and sealing washer supplied in the connections pack, when fitted to the safety valve, will extend the valve below the boiler. The discharge pipe must be extended using pipe not less than 15 mm o.d. to discharge in a visible position outside the building, facing downward preferably over a drain. IMPORTANT NOTE: To facilitate servicing of the appliance, the discharge pipe MUST ONLY be extended using a compression fitting supplied. The pipe must have a continuous fall and be routed to a position so that any discharge of water, possibly boiling or steam, cannot create any danger to persons, damage to property or external electrical components and wiring. Tighten all pipe connection joints.
9.4 Filling loop extension knob F24E Only
The filling loop extension knob is supplied in the discharge safety valve pipe connection pack. Fit to the filling device on/ off knob, this is a push fit, see diagram 9.2.
9.5 Filling loop extension knob F18E SB
KNURLED UNION NUT finger tighten only
The filling loop extension is not required for this boiler, it can be discarded.
DISCHARGE SAFETY VALVE PIPE Diagram 9.1

FILLING DEVICE

FILLING LOOP EXTENSION

Diagram 9.2

10 Horizontal Telescopic Top Flue Installation

SIDE FLUE

L 70mm 65mm
Suitable for installations that require a flue length "L" from 430 minimum to 660 maximum. If longer flueing is required extensions and bends are available, see note below. If the flue length, see diagram 10.2. is less than 430 'L' Do Not cut this flue but use the horizontal top flue 86285. Note: Additional 1 metre extensions, 90 and 45 bends are available. The maximum extended flue is 3.5m. The use of flue bends requires the max extended flue lengths to be reduced by 1m. for 90 and 0.5m. for 45.
10.1 Horizontal Telescopic Top Flue Kit of parts, refer to diagram 10.1. 10.2 Horizontal telescopic flue system Rear and side flue lengths and dimensions, see diagram 10.2.
Note : Top of boiler casing not front panel

410 mm

20mm * refer to diagram 6.1 Min. Clearance
Drill, Screw and Tape (not supplied)

REAR FLUE

D G* H* F* C

70mm 184mm 65mm

The flue kit A2004500 is 660 mm long and comprises: - Telescopic flue assembly.. A - Fixing collar seal... B - Fixing collar... C - Elbow... D - External rubber sealing collar. E - *Gasket... F - *Screws 6 off... G - *'O' rings... H - *Screws 4 off.. J
* supplied in plastic bag

Telescopic Top flue kit

EXTERNAL FROST THERMOSTAT

STRAIN RELIEF

MAINS CABLE
EXTERNAL CONTROLS CABLE Diagram 11.4

F24E only

TO MAIN PCB CONNECTOR J15

CONTROLS INTERFACE PCB

DO NOT CONNECT MAINS VOLTAGE HEATING CONTROLS CONNECTION PLUG
VOLTAGE FREE HEATING CONTROLS CONNECTION (ON CONTROLS BOX COVER)
REMOVE LINK WHEN ANY EXTERNAL CONTROLS ARE USED
11.4 Electrical Connections - Testing
Carry out preliminary electrical system checks as below:

PROGRAMMER

ON/OFF SWITCH
1. Test insulation resistance to earth of mains cables. 2. Test the earth continuity and short circuit of cables. 3. Test the polarity of the mains.

EXTERNAL ROOM THERMOSTAT

EXTERNAL JUNCTION BOX 3 AMP FUSE

INTERNAL PROGRAMMER

CONTROL PANEL USER INTERFACE RETAINING LATCHES
EXTERNAL 230V AC ROOM THERMOSTAT EXTERNAL 230V AC FROST THERMOSTAT

DOUBLE POLE ISOLATOR

230V~ 50Hz PERMANENT MAINS SUPPLY
The type of plug and orientation may be different to that illustrated but the wiring should always be as wiring diagrams PLUG
EXTERNAL CONTROLS CABLE(MAINS VOLTAGE)
ON/OFF SWITCH EXTERNAL PROGRAMMER
EXTERNAL PROGRAMMER/CLOCK EXTERNAL 230V AC ROOM THERMOSTAT
CONTROLS INTERFACE PCB Diagram 11.3
EXTERNAL 230V AC FROST THERMOSTAT

Diagram 11.5

F18E SB only

12 Commissioning

Important: The commissioning and first firing of the boiler must only be done by a competant person.

Air in pipes

Important: A central heating system can not operate correctly unless it is filled with water and air bled from the system. If these conditions are not met the system may be noisy. Bleed the air in the radiators and adjust the pressure if system requires. If the system requires filling to often this may be due to minor leaks or corrosion in the system.

Gas installation

If conversion from G20 to 30 or 31 is required, refer to section 13. It is recommended that any air is purged from the supply at the gas purge point on the gas valve, see diagram 12.1.

Filling the system

The following steps 1 - 8, show how to fill the system.
BURNER PRESSURE POINT GAS PURGE POINT
The boiler is connected to the electrical supply. The gas service cock is open. Turn the switch OFF ( 0 )
F24E shown 2. Open the three water isolating valves.

Diagram 12.1

Note: Isolating valves are shown in the: OFF position
HEATING RETURN F24E shown
COLD WATER IN (F24E Only)

HEATING FLOW

DOMESTIC HOT WATER OUT (F24E Only)

GAS SERVICE COCK

3. Undo cap on automatic air vent on top of pump and leave undone.

Instruct the User

Instruct and demonstrate the lighting procedure and advise the user on the safe and efficient operation of the boiler. Instruct on and demonstrate the operation of any heating system controls. Advise the user on the use and maintenance of any scale reducer and pass on any relevant instructional documents. Advise that to ensure the continued efficient and safe operation of the boiler it is recommended that it is checked and serviced at regular intervals. The frequency of servicing will depend upon the installation conditions and usage, but in general, once a year should be enough. Draw attention, if applicable, to the current issue of the Gas Safety (Installation and Use) Regulations, Section 35, which imposes a duty of care on all persons who let out any property containing a gas appliance in the UK. It is the Law that any servicing is carried out by a competent person. Advise the user of the precautions necessary to prevent damage to the system, boiler and the building, in the event of the heating system being out of use during frost or freezing conditions. Advise the user that the permanent mains electrical supply SHOULD NOT be switched off, as the built in frost protection and pump saver program would not be operable. Reminder, leave these instructions and the Benchmark logbook with the user.

Completion

Adjust the boiler temperature control and any system controls to their required settings. For IE, it is necessary to complete a "Declaration of Conformity" to indicate compliance to I.S.813. An example of this is given in the current edition of I.S.813.

13 Changing Gas Type

Should it be necessary to change the gas type, a conversion kit with instructions will be required. This modification must only be carried out by a competent person. Conversion natural gas (G20) to G30/G31 Part No. A20027. Unclip the control box, see diagram 11.1. Run the appliance in heating mode. Read the burner pressure setting in heating mode, before the boiler modulates. Adjust the central heating output to the minimum setting by adjusting potentiometer P3, refer to commissioning section. Adjust the potentiometer P6 burner pressure to the desired value, by inserting a small flat edge screw driver into the arrowed slot, turn to adjust to the desired setting, see diagram 12.2. Return the potentiometer P3 to its initial value.
Setting the step pressure.

18.1 Central heating thermistor
Before starting refer to the front of Section 18 Important information. Remove the front panel, refer to Section 15.3. Lower the control panel, refer to Section 15.4.

18.2 Fan.

Before starting refer to the front of Section 18 Important information. Remove the front panel, refer to Section 15.3. Remove the sealed chamber cover, refer to Section 15.5. Remove the fan, refer to Section 15.10.
RETAINING CLIPS AIR PRESSURE SWITCH ELECTRICAL CONNECTORS SENSING TUBE

18.3 Air pressure switch

Before starting refer to the front of Section 18 Important information. Remove the front panel, refer to Section 15.3. Remove the sealed chamber cover, refer to Section 15.5. Locate air pressure switch situated at the top right hand side, see diagram 18.3. Remove air pressure switch tube. Note: Do not fit tube until the air pressure switch is in position. Disconnect air pressure switch electrical connections. Unclip to remove air pressure switch.
Diagram 18.3 COLD WATER INLET RESTRICTOR
18.4 (F24E Only) Domestic water inlet filter
If the water flow rate through the appliance has reduced it may be necessary to clean or replace the water inlet filter, refer to section 15.12. Before starting refer to the front of Section 18 Important information. Remove the front panel, refer to Section 15.3. Lower the control panel, refer to Section 15.4. Clean or replace the water inlet filter, refer to Section 15.12.
COLD WATER IN ISOLATING VALVE
18.5 Central Heating Filter
It may be necessary to clean or replace the central heating filter. Before starting refer to the front of Section 18 Important information. Isolate flow and return valves (a) and (c). Clean or replace the central heating filter, refer to Section 15.13. Lower the control panel, refer to Section 15.4. Remove the sealed chamber cover, refer to Section 15.5. Remove the combustion chamber cover, refer to Section 15.7. Remove burner from boiler, refer to Section 15.9.

Diagram 18.4

18.6 ( F24E Only) Cold water inlet restrictor
Before starting refer to the front of Section 18 Important information. Remove the front panel, refer to Section 15.3. Lower the control panel, refer to Section 15.4. Isolate cold water inlet valve (b). Drain down domestic hot water circuit of boiler only, refer to relevant part of diagram 18.1. Undo union nuts from boiler cold water in isolating valve. Clean and inspect restrictor, replace if necessary, see diagram 18.4.

18.18 230V Controls board, refer to diagram 18.10.
Before starting refer to the front of Section 18 Important information. Remove the front panel, refer to Section 15.3. Unclip control panel user interface and hinge forward. Do not strain the cables. Disconnect the electrical connection from the 230V controls board and the electrical connection from printed circuit board (PCB). Remove the 230V controls board retaining screw. Remove the 230V controls board.
18.20 Central heating pump head, refer to diagram 18.11.
Before starting refer to the front of Section 18 Important information. Remove the front panel, refer to Section 15.3. Lower the control panel, refer to Section 15.4. Drain down central heating water circuit of the boiler only, refer to relevant part of diagram 18.1. Note: it is not necessary to drain down the entire heating system to carry out this work. For ease of access if required remove the right hand side panel, refer to Section 15.6. Undo four head fixing screws and remove pump head. Gain access to the pump electrical connection box and remove cover. Disconnect pump cable from pump (avoid straining cables). Connect electrical connection to replacement pump head. Fit replacement pump head.
18.19 (F24E Only) Analogue programmer, refer to diagram 18.10
18.21 (F24E Only) Filling system tap, refer to diagram 18.12.
Before starting refer to the front of Section 18 Important information. Remove the front panel, refer to Section 15.3. Lower the control panel, refer to Section 15.4. Drain down the hotwater circuit, refer to relevant part of diagram 18.1. Pull of the filling loop tap extension. Pull out slotted metal clip securing tap into housing, remove tap. Pull out slotted metal clip and remove pipe from tap.
18.22 (F24E Only) Reduced pressure zone valve (RPZ), refer to diagram 18.12.
Before starting refer to the front of Section 18 Important information. Remove the front panel, refer to Section 15.3. Lower the control panel, refer to Section 15.4. Drain down the boiler only, refer to relevant part of diagram 18.1. Pull out slotted metal clip securing pipe to RPZ. Pull out slotted metal clip securing RPZ into housing, remove RPZ.
WATER FLOW SENSOR Diagram 18.14 BYPASS VALVE
SYSTEM WATER PRESSURE SENSOR
Before starting refer to the front of Section 18 Important information. Remove the front panel, refer to Section 15.3. Lower the control panel, refer to Section 15.4. Drain down the boiler only, refer to relevant part of diagram 18.1. Pull out slotted metal clip securing boiler drain valve into housing, remove boiler drain valve.

18.28 Gas Control valve, refer to diagram 18.17.
Before starting refer to the front of Section 18 Important information. Remove the front panel, refer to Section 15.3. Lower the control panel, refer to Section 15.4. Disconnect gas supply pipes union nuts at the gas control valve. Disconnect supply pipe union nut at the burner injector bar. Remove the locking nut and brass washer from underside of gas control valve. Ease gas control valve forwards and disconnect electrical connections to gas control valve. Withdraw gas control valve assembly.

Diagram 18.18

PRESSURE RELIEF VALVE
Note: Use the new washers supplied with the gas control valve. Fit gas valve restrictor to replacement gas control value. Fit replacement gas control valve. Check the Min. gas pressure and if it requires adjusting, refer to Section 13 Changing Gas Type.

Diagram 18.19

9768 9769
18.29 Gas control valve stepper motor, refer to diagram 18.18
Remove the front panel, refer to Section 15.3. Lower the control panel, refer to Section 15.4. Remove the gas control valve, refer to Section 18.28. Disconnect the electrical connection from stepper motor. Remove the two screws securing stepper motor to the gas control valve. Fit replacement gas control valve stepper motor. Note: Take care not to damage the 'O' ring.
18.30 Discharge safety valve, refer to diagram 18.19.
Before starting refer to the front of Section 18 Important information. Remove the front panel, refer to Section 15.3. Lower the control panel, refer to Section 15.4. Undo discharge pipe union nut. Pull out slotted metal clip from valve body and remove valve.
18.31 (F24E Only) Three-way valve head, refer to diagram 18.20.
Before starting refer to the front of Section 18 Important information. Remove the front panel, refer to Section 15.3. Lower the control panel, refer to Section 15.4. Remove gas control valve, refer to Section 18.28. (It will not be necessary to remove the gas control electrical cables). Remove electrical plug from valve head. Pull out slotted metal clip from valve body and remove valve head from body. Fit replacement valve head. Note : 1) When refitting clip, ensure that letters YES are as shown. 2) It is not necessary to drain boiler to carry out this work.

THREE WAY VALVE ACTUATOR

Diagram 18.21

IGNITION UNIT

Diagram 18.22
THREE WAY VALVE HEAD Diagram 18.20 THREE WAY VALVE/ BYPASS HOUSING
Before starting refer to the front of Section 18 Important information.
18.32 (F24E Only) Three-way valve actuator, refer to diagram 18.21.
Remove the front panel, refer to Section 15.3. Lower the control panel, refer to Section 15.4. Drain down the boiler only, refer to relevant part of diagram 18.1. Remove the gas control valve, refer to Section 18.28. Remove 3-way valve head, refer to Section 18.31. Remove the three way valve actuator.
18.33 Ignition unit, refer to diagram 18.22.
Remove ignition unit securing screw. Pull upwards to release and remove the ignition unit from the retaining slot.
18.34 (F24E Only) Domestic hot water plate to plate heat exchanger
Disconnect electrical connections.

Diagram 18.23

EXPANSION VESSEL

9772 9773

For ease of access remove the left hand side panel, refer to Section 15.6.
Remove the front panel, refer to Section 15.3. Lower the control panel, refer to Section 15.4. Drain down the boiler and hotwater circuit ,refer to relevant parts of diagram 18.1. Unclip the central heating thermistor. Unscrew the heating flow pipe union nut, swing pipe forwards. Remove the gas supply pipe between the gas control valve and injector bar, see diagram 18.23. Disconnect the union connection from the expansion vessel. Supporting domestic hot water plate to plate heat exchanger, unscrew and remove two screws securing it onto pump mounting and 3-way valve/bypass housing. Remove plate to plate heat exchanger from boiler. Fit replacement plate to plate heat exchanger. Note: Plate to plate heat exchanger mounting screws are offset to ensure correct fitting.

Diagram 18.24

DOMESTIC HOT WATER PLATE TO PLATE HEAT EXCHANGER
Renewal of the expansion vessel requires the boiler to be removed from the wall. As an alternative, a separate expansion vessel of the same specification may be connected as close as possible to the boiler, leaving the original in position, refer to the installation instructions. Replacing the expansion vessel Before starting refer to the front of Section 18 Important information.
IMPORTANT: With regards to the manual handling operations, 1992 regulations, the following operation exceeds the recommended weight for one man lift. Remove the front panel, refer to Section 15.3. Lower the control panel, refer to Section 15.4. Drain down the boiler only ,refer to relevant parts of diagram 18.1. Disconnect the flue system.
Disconnect the pressure relief valve discharge pipe. Disconnect the mains cable and any external controls cables. Lift up to remove the boiler from the wall. Remove sealed chamber cover, refer to Section 15.4. Remove the right hand side panel, refer to Section 15.6. From the rear of the boiler, unclip wiring harness retaining wire. Undo pipe coupling on expansion vessel. Unscrew and remove expansion vessel bracket retaining screw.

Note: Check that expansion vessel pressure is correct, see Section 1 Technical Data.
18.36 Sealed chamber cover seal, refer to diagram 18.25
Before starting refer to the front of Section 18 Important information. Remove the front panel, refer to Section 15.3. Remove the sealed chamber cover, refer to Section 15.5. Remove the old seal, thoroughly clean the casing. Fit the new seal, it is supplied to the correct length. Note: Ensure the seal is fitted correctly giving an air tight seal.
SEAL SEALED CHAMBER COVER Diagram 18.25
Slide expansion vessel to the left and forward to remove.

FRONT PANEL

Disconnect the fixing jig connection pipes at the boiler.
For this operation the boiler must be removed from the wall.

18.35 Expansion vessel

19 Spare parts
When ordering spare parts, quote the part number and description, stating the appliance model number and serial number from the data badge.
Short parts list No. Description Central heating thermistor Fan Air pressure switch F24E only Domestic water flow sensor Printed circuit board - Main Pump head System water pressure sensor Gas control valve (G20) Gas control valve (G30) Discharge safety valve Overheat thermostat Ignition electrode Flame sense electrode 230V controls board User interface PCB Stepper motor (G20) Stepper motor (G30) Ignition unit F24E only Three way valve head Three way valve actuator Heat exchanger Burner Part No. S57398 S10088 S10089 S57202 S10082 S10052 S57205 S10045 S10046 S10067 S10080 S10038 S10037 S10091 S10081 S57434 S57435 S57427 S57206 S10064 S10030 S10042 G.C. No.
Because of our constant endeavour for improvement details may vary slightly from those in the instructions.