Heating and hot water for the professionals
Installation and Servicing Instructions

THEMA F

THIS IS A CAT II2H3+ APPLIANCE
IN WARRANTY TECHNICAL HELPLINE

01773 828400

01773 828100
INSTALLATION AND SERVICING INSTRUCTIONS
THEMA F 23 E - THEMA F SB 18 E - THEMA F SB 23 E
Note! The boiler serial number is marked on the label attached to the inside of the boiler. Refer to the 'Introduction' section page 3 for a description of the basic functions of the boiler. To safely operate the boiler, refer to the Users Instructions.

INSTALLATION SECTION

Introduction.. Page 3 Dimensions... 3 Technical data.. 4 - 5 Boiler schematic.. 6 Fixing jig... 7 Domestic hot water system design. 7 Heating system design... 8 Piping system installation.. 8 Boiler location... 9 Boiler installation.. 10 Rear outlet flue installation.. 11 - 12 Top outlet flue installation.. 13 Electrical connection... 14 Commissioning.. 15 - 16 Safety devices... 16 Settings... 17 Changing gas type.. 17

SERVICING SECTION

Routine cleaning and inspection. Page 18 - 19 Replacement of parts.. 19 - 24 Microswitch assembly... 19 Fan... 19 Air pressure switch.. 19 Spark generator... 19 Main printed circuit board.. 19 Ignition printed circuit board.. 20 Pump... 20 Temperature/Pressure gauge.. 20 Reversing valve assembly.. 20 Reversing valve front section.. 21 Loss of water switch.. 21 Water valve or diaphragm.. 21 Gas valve... 22 Modulating coil... 22 Central heating safety valve.. 23 Heat exchanger.. 23 Expansion vessel.. 23 Boiler thermistor... 23 Overheat thermostat.. 24 Combustion chamber insulation.. 24 Ignition electrode.. 24 Flame sense electrode.. 24 Burner... 24 Burner injectors.. 24 Timeclock... 24 Schematic wiring diagram.. 25 Fault finding... 26 - 27 Spare parts... 27
Mandatory warning notice for CEE countries WARNING, this appliance is designed, approved and inspected to meet the requirements of the English market. The identification plate located on the inside of the appliance certifies the origin where the product was manufactured and the country for which it is intended. If you see any exception to this rule, please contact your nearest Saunier Duval dealer. Thank you in advance for you assistance.

INTRODUCTION

The THEMA F 23 E boiler is a wall mounted modulating combination boiler with electronic ignition providing central heating and instantaneous domestic hot water. Both the central heating and domestic hot water temperature are user adjustable from the boiler control panel. Domestic hot water demand always has priority over heating demand. The THEMA F SB 18 E and SB 23 E boilers are wall mounted modulating boilers with electronic ignition providing central heating only. The central heating temperature is user adjustable from the boiler control panel. The boilers are of the II2H3+ category for use with Natural Gas (G20) as distributed in the United Kingdom, or with Butane or Propane gas (G30/G31) with the appropriate conversion kit. Conversion kits: Conversion Part No. Natural Gas (G20) to G30/GBoilers burning LPG or similar gases MUST NOT be fitted in basements or below ground level. The boiler has a fan assisted balanced flue which both discharges the products of combustion to and draws the combustion air from the outside air.

Diagram 1

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. Refer to the flue fitting instructions. Electrical components have been tested to meet the equivalent requirements of BEAB. The boiler is designed for use as part of a sealed water central heating system with fully pumped circulation. The pump, expansion vessel and associated safety devices are all fitted within the boiler. The boiler can be installed against either an external wall or on an adjacent inside wall, that is, the flue system will pass directly to the rear or to either side to the terminal fitted on the outside wall face. The installation must be carried out by a competent person in accordance with the relevant requirements of The Building Regulations, The Water Byelaws, The Building Standards (Scotland) Regulations and any applicable local regulations. Ancillary equipment A range of flue accessories are available including vertical flues, twin-pipe flues, bends etc. For further information contact your supplier.

THEMA F 23 E

THEMA SB 18 E and SB 23 E

DIMENSIONS

Diagram 2
Net weight: 41 kg Gross weight : 43 kg
The boiler is delivered in three separate packages: - The boiler - The fixing jig - The flue system

Hab 271a

TECHNICAL DATA
THEMA F SB 18 E THEMA F SB 23 E 1,2,70 1,13 0,4,8 2,01 1,13 0,4,8 1,98 0,97 2,3,88 1,63 1,63 THEMA F 23 E Heating output Efficiency Heating adjustment Expansion vessel effective capacity Expansion vessel charge pressure Maximum system capacity at 75C Safety valve, maximum service pressure Products outlet diameter Fresh air inlet diameter Hot water output automatically variable from (kW) (BTU/H) to (kW) (BTU/H) (%) (l) (bar) (l) (bar) ( mm) (mm) automatically variable from (kW) (BTU/H) to (kW) (BTU/H) (C) ( l/min) (l/min) (l/min) (bar) (bar) (V) (W 8,9 30,000 23,3 80,9,0,150
8,9 8,9 8,9 30,000 30,000 30,000 23,3 18,5 23,3 80,000 63,000 80,000 91,5 90,5 91,5 38C to 90C 6,5 6,5 6,5 0,5 0,5 0,100 230 150
Maximum hot water temperature Specific flow rate (for 30C temp rise) Threshold flow rate Nominal water flow rate Maximum supply pressure Minimum operating pressure Electrical supply Maximum absorbed power

Natural Gas (G20)

Burner injector Inlet pressure Diaphragme Gas rate (maximum) Gas rate (minimum) Burner injector Inlet pressure Diaphragme Gas rate (maximum) Gas rate (minimum) Burner injector Inlet pressure Diaphragme Gas rate (maximum) Gas rate (minimum) Burner injector Inlet pressure Diaphragme Gas rate (maximum) Gas rate (minimum)
mm mbar mm m3/h m3/h mm mbar mm kg/h kg/h mm mbar mm kg/h kg/h mm mbar mm m3/h m3/h
1,2,70 1,13 0,4,8 2,01 1,13 0,4,8 1,98 0,97 2,3,88 1,63
1,2,17 1,13 0,3,2 1,62 1,13 0,3,2 1,60 0,97 2,

Town gas (G130)

Propane (G31)

Butane (G30)

Pressure table :
(kW) (Btu/h) (kW) (Btu/h)
Heat output 8,23,Heat input 11,9 13,2 14,4 15,7 16,9 18,1 19,2 20,4 21,5 22,7 23,8 24,9 26,0 26,9 28,91713 96602
2,1 5,3 6,3 2,6 6,3 7,5 3,0 7,4 8,8 3,5 8,6 10,2 4,0 9,8 11,7 4,5 11,1 13,3 5,1 12,5 14,9 5,7 13,9 17,2 6,3 15,5 20,1 6,9 17,0 20,3 7,6 18,6 22,2 8,3 20,4 24,4 8,8 21,7 26,0 9,8 24,1 28,8
G 20 G 30 G 31 (mbar) 1,3 (mbar) 3,7 (mbar) 4,0

Pump :

The performance of the pump varies according to the pump bypass setting, see diagram 3.
Available pressure (kPa) between heating flow and return

(10 kPa = 1 m WG)

Pom 052
1 Bypass fully shut 2 Open 1/4 turn 3 Open 1/2 turn 4 Open 1 turn 5 Open 2 turns
Flow rate through heating system (I/h)

Diagram 3

BOILER SCHEMATIC
24 Ignition module Heating temperature adjuster Hot water temperature adjuster Temperature/ressure gauge Expansion vessel Pump Automatic air vent Burner Heat exchanger bleed pipe Heatexchanger Gas valve Heating and hot water thermistor Ignition electrode Overheat thermostat Flame sense electrode Loss of water pressure switch Fan Air pressure switch Gas cock

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.

255 mini

50 mini

Diagram 7

The boiler must be installed so that the terminal is exposed to the external air. Note: Under certain weather conditions the flue may produce a plume of condensation, this is quite normal. If the terminal is fitted within 850mm of a plastic or painted gutter or 450m of painted eaves, an aluminium shield of a minimum length of 750mm should be fitted to the underside of the gutter or painted surface. Should any doubt exist as to the permissible position of the terminal, contact the Saunier Duval Technical Helpline 01773 828400. Cupboard or compartment ventilation The boiler can be fitted in a cupboard or compartment without need for permanent ventilation.
Minimum dimensions (in mm) for the positioning of flue terminals
A - Under a window.. 300 B - Under an air vent.. 300 C - Under a gutter.. 75 D - Under a balcony.. 300 E - From an adjacent window.. 300 F - From an adjacent air vent.. 300 G - From vertical drain pipes or soil pipes. 75 H - From an external corner of the building.. 300 I - From an internal corner of the building. 300 L - From the ground or from another floor. 300 M - Between two terminals vertically.. 1500 N - Between two terminals horizontally. 300

G C E F M

A B D I H L

Diagram. 8

Diagram 12

Diagram 13
Table 1 Flue cutting lengths
Cutting length (mm) Flue option Rear outlet Side flue to left (Diagram 13) Rear outlet Side flue to right (Diagram 14) outer pipe e + a + 96 inner pipe e + a + 173 Comments maximum distance 'X' without extension 1080 mm maximum distance 'x' without extension 1080 mm

e + a + 154

e + a +231

Hab 209

Diagram 14

Hab 208

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 2, measure dimensions a and e, see diagram 13 or 14. Cut both the inner and outer pipe to the dimensions given in table 3. 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-direct rear flue Fit rubber sealing collar (C) into groove at the outer end of pipe (A), see diagram 16. Fit outer pipe (A) into wall with groove to the outside. Pull pipe inwards to bring rubber sealing collar hard up against external wall, see diagram16. Fit internal plastic flange (F) onto outer pipe. Push along the pipe until engaged against internal wall. From inside, insert inner pipe (B) into outer pipe turning anti-clockwise to allow inner to fully enter outer pipe. Fit rubber sleeve (H) onto outer pipe. Take hold of inner flue,twist clockwise and push gently onto fan outlet. Pull rubber sleeve onto boiler spigot ensuring a good seal. Installation of flue assembly-side flue Fit rubber sealing collar (C) into groove at the outer end of pipe (A), see diagram 16. Fit outer pipe (A) into wall with groove to the outside. Pull pipe inwards to bring rubber sealing collar hard up against external wall, see diagram16. Fit internal plastic flange (F) onto outer pipe. Push along the pipe until engaged against internal wall. From inside, push inner pipe (B) into outer pipe turning anti-clockwise to allow inner to fully enter outer pipe. Fit rubber sleeve (H) onto outer pipe. Fit both 'O' rings (F) into 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. Pull rubber sleeve onto elbow ensuring a good seal.

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.

Sec 055

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.

SAFETY DEVICES

Air flow rate safety device If an obstruction, even partial, of the flue occurs, for any reason whatsoever, the built in safety system of the boiler will turn the boiler OFF and the fan will continue to run. The boiler will be ready to operate when the fault has been cleared. In case of power supply failure The boiler no longer operates. As soon as power supply is restored, the boiler will be automatically restarted. Overheat safety In the event of a problem, the overheat thermostat causes safety shutdown of the boiler. Should this occur, reset the thermostat by pressing in the red button. The overheat thermostat is located on the RHS of the heat exchanger. Important notice: A central heating system cannot operate satisfactorily unless it is properly filled with water and unless the air initially contained in the piping systems has been properly bled off. If these conditions are not satisfied, air noise will occur within the system. The THEMA F 23 E boiler has a built in frost protection device that protects the boiler from freezing. If the boiler is to be left and there is a risk of frost, ensure that the gas and electrical supplies are left connected and the summer/winter switch is in the position. 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. Note: This device works irrespective of any room thermostat setting and only protects the boiler.

Reg 056

Des 044

SETTINGS

Gas valve setting All boilers are tested and factory set during manufacture. Should it be necessary to reset a gas valve, for example after replacement, proceed as follows: Shut down boiler. Connect a suitable pressure gauge as described in 'Commissioning'. Maximum setting Remove one electrical connector from the modulating gas valve coil. Turn the domestic hot water temperature adjuster to maximum setting. Remove the protective cover B A from the gas valve adjuster. Using a 2 mm rod, press in the spindle in the middle of screw M, see diagram 25. Turn nut 'B' to obtain the desired pressure, see technical data. Minimum setting This must be done AFTER the maximum setting. Hold not B to prevent from turning, turn nut 'A' to obtain the desired pressure, see technical data. After adjustment, refit the cover to the gas valve adjuster and refit electrical connector. Bypass The THEMA F 23 E has a built-in bypass. This must be adjusted according to the requirements of the system, refer to the flow rate pressure curve (diagram 3). The boiler is supplied with the built-in bypass open a half a turn. It is adjusted by turning the bypass screw (a), see diagram 26. Turn the screw clockwise to close the bypass. When using thermostatic radiator valves (TRV's), it is recommended that an additional, adjustable bypass of 15 mm minimum diameter is fitted between the flow and return of the heating circuit, see diagram 6. Any bypass must be fitted before system controls. PCB Settings The PCB on the Thema F 23 E can be set to operate in different ways to suit individual installations. The dip switch SW1, see diagram 27, should be set as follows: 1 - OFF 2 - ON 3 - OFF 4 - OFF 5 - OFF 6 - OFF

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.

Hab 286

Sch 228
Fit replacement PCB in reverse order to removal. Important: When fitting replacement PCB, ensure that control knob spindles correctly locate into PCB adjuster slots. Refit connectors and covers in reverse order to removal. To replace ignition PCB Gain access to PCB's as described in previous section. Remove main PCB securing screw as described in previous section. Pull off three electrical connectors on PCB. Lift up ignition PCB, separate from main PCB and remove from boiler. Fit replacement PCB in reverse order to removal. Refit connectors and covers in reverse order to removal. To replace pump Drain down heating circuit of boiler only as follows: Close isolating valves on flow and return connections on fixing jig, see diagram 5. Note: These valves are closed when slots are at right angles to direction of flow. It is not necessary to drain entire heating circuit to carry out this work. Drain boiler by attaching a plastic tube to drain outlet and opening drain valve knob anticlockwise, see diagram 5. Gain access to pump connection as described in 'To replace main PCB'. Pull off pump connector and earth lead. Pull out retaining clip from telescopic pump outlet connection and slide connection upwards to release from pump. Undo and remove two fixing screws and remove pump retaining bracket from front of pump. Grasp pump body, lift upward to disengage from reversing valve and turn pump to right. Remove pump by pulling forward and over reversing valve assembly. Discard old pump inlet 'O' ring. Apply silicone grease to new 'O' ring supplied, and fit onto inlet connection on replacement pump. Fit replacement pump in reverse order to removal. Note: Apply silicone grease to pump outlet connection 'O' ring before assembly. Refit pump electrical connection. Open isolating valves on flow and return connections, refill, vent and pressurise boiler. Check for leaks. To replace temperature/pressure gauge Drain down heating circuit of boiler only as described in 'To replace pump'. Undo and remove screw securing pressure gauge capillary to front section, see diagram 31. Carefully pull capillary from front section. Undo and remove two screws securing temperature/pressure gauge to lower front panel and remove gauge. Fit replacement gauge in reverse order to removal.

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 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.

Diagram 37

Unclip thermistor from pipe. Pull off electrical cennections from thermistor. Fit replacement thermistor in reverse order to removal. Note: No heat sink compound is required. The polarity of the connections is not important. To replace overheat thermostat Locate the overheat thermostat on the right hand side of the heat exchanger. Pull off the electrical connections from the thermostat. Unscrew and remove two screws holding thermostat to heat exchanger. Fit replacement thermostat in reverse order to removal, using heat sink compound on the contact surface of thermostat. Refit electrical leads, the polarity is not important. To replace combustion chamber insulation Front section Remove combustion chamber from boiler as described in 'Routine Cleaning and Inspection'. Slide side panels out of combustion chamber sides. Lift front insulation panel free from retaining lugs and away from cover. Fit replacement panels in reverse order to removal. Rear panel Remove burner from boiler as described in 'Routine Cleaning and Inspection'. Remove clip from base of insulation panel. Pull bottom edge of insulation panel forward, downward and out from behind heat exchanger. Fit replacement panel in reverse order to removal. Replace burner into boiler in reverse order to removal. To replace ignition electrode Remove combustion chamber from boiler as described in 'Routine Cleaning and Inspection'. Pull off ignition leads from ignition electrode. Unscrew and remove two screws holding ignition electrode onto burner. Fit replacement ignition electrode in reverse order to removal. Refit ignition leads, the polarity is not important. To replace flame sense electrode Remove combustion chamber from boiler as described in 'Routine Cleaning and Inspection'. Pull off lead from flame sense electrode. Unscrew and remove screw holding earth lead to flame sense electrode. Unscrew and remove screw holding flame sense electrode onto burner. Fit replacement flame sense electrode in reverse order to removal. Refit lead. To replace burner Pull off ignition and flame sense leads from electrodes. Remove burner from boiler as described in 'Routine Cleaning and Inspection'. Remove ignition and flame sense electrodes as described in previous sections. Unscrew and remove two screws holding burner injector bar to burner and remove injector bar. Asemble replacement burner, supplied in parts, as follows: Fit burner injectors to injector bar and tighten. Assemble burner elements (14) into front and rear burner supports with securing pins and rods, using original burner for guidance. Fit burner injector bar to burner. Fit ignition and flame sense electrodes to burner. Fit replacement burner to boiler in reverse order to removal. Reconnect ignition and flame sense leads to electrodes. Reconnect earth lead to flame sense electrode. The polarity of the ignition leads is not important. To replace burner injectors Remove burner as described previously. Remove ignition and flame sense electrodes as described in previous sections. Unscrew and remove two screws holding burner injector bar to burner and remove injector bar. Unscrew and remove burner injectors from burner bar. Fit replacement injectors to injector bar and tighten. Note: make sure that injector size, marked on each injector, is the same as that given in 'Technical Data'. Reassemble burner and replace into boiler in reverse order to removal. To replace timeclock Gain access to rear of lower control panel as described in 'Routine Cleaning and Inspection'. Unscrew and remove two screws holding timeclock to lower control panel. Remove PCB cover. Remove timeclock plug from connection CN7 on main PCB. Fit replacement timeclock in reverse order to removal.

SCHEMATIC WIRING DIAGRAM

IG P SW3 K4 K5 EV1 TA CTN EV AL FA FL TRA Pr EX ON/OFF switch Pump Microswitch Hight limit thermostat Loss of water switch Gas valve modulating coil Room thermostat (if fitted) Boiler thermistor Gas valve Ignition unit Ignition electrode Flame sense electrode Transformer Air pressure switch Fan

THEMA F 23 E PCB

6.13 6.14

6.15 6.11

6.12 6.9

6.8 6.6 6.4 6.2

2.2 14.6 2.1 9.1 9.2 8.4 8.3 8.2 8.1 14.4 14.3 14.7 14.2 14.1 14.5
13.4 13.1 12.2 13.3 12.1 13.2
THEMA F SB 18 E and THEMA F SB 23 E PCB

Ra TH K5

6.12 6.9 6.8 6.6 6.4 6.2
IG P K4 K5 EV1 TA CTN EV AL FA FL TRA Pr EX TH
ON/OFF switch Pump Hight limit thermostat Loss of water switch Gas valve modulating coil Room thermostat (if fitted) Boiler thermistor Gas valve Ignition unit Ignition electrode Flame sense electrode Transformer Air pressure switch Fan Cylinder thermostat

3.3 3.2 3.1

13.4 13.1 12.2 12.1 13.2 13.3

Diagram 39

Sch 240

Sch 242

Diagram 38

FAULT FINDING

Prior to fault finding, check : Inlet gas pressure = 20 mbar Electrical supply = 240 V - 50 Hz Central heating system is pressurised at 1 - 1,5 bar. Overheat thermostat on RHS of heat exchanger has not tripped reset if necessary. Carry out electrical system checks i.e. earth continuity, resistance to earth, short circuit and polarity with a suitable meter. Note : these must be repeated after any servicing or fault finding. Ensure that all external controls are correctly wired and calling for heat. The fault finding charts will enable the majority of faults to be diagnosed. To use the charts effectively, it is necessary to determine exactly which aspects of the boiler are working correctly and which are not. For example: If the domestic hot water works but the heating doesnt, refer to chart No. 1. If heating works correctly but the hot water doesnt, refer to chart No. 2. IMPORTANT: Always adopt a logical, step by step procedure starting at the beginning of the appropriate fault finding chart. WARNING. Always isolate the boiler from the electrical supply before carrying out any electrical replacement work. Always check for gas soundness after any service work.

NO CENTRAL HEATING

Turn ch temp. control to max. does burner fire ?

Does pump run ?

Refer to chart n3

Does fan run ?

Refer to chart n4
Is short selector lever on front of reversing valve in right hand position ?
Does burner fire when a hot tap is opened ?

NO YES

Refer to chart n2

Spare Parts

REMEMBER, When replacing a part on this appliance, use only spare parts that you can be assured conform to the safety and performance specification that we require. Do not use reconditioned or copy parts that have not been clearly authorised by Hepworth Heating Ltd. If a part or advice is required contact the relevant service organisation or Heatcall using the telephone number on the inside front cover of this booklet. Please quote the name of the appliance, this infomation will be on the name badge on the front of the appliance.
To ensure the continued efficient and safe operation of the appliance it is recommended that it is checked and serviced as necessary at regular intervals, but in general once a year should be enough, refer to guarantee registration on the inside front cover of this literature. If this appliance is installed in a rented property there is a duty of care imposed on the owner of the property by the current issue of the Gas Safety (Installation and Use) Regulations, Section 35. Servicing/maintenance should be carried out by a competent person in accordance with the rules in force in the countries of destination. To obtain service, please call the relevant service organisation or Saunier Duval Service using the telephone number on the inside front cover of this literature.
User Controls and Lighting
Central heating temperature selector minimum setting (approx. 38C) up to maximum setting (approx. 73C). Boiler ON indicator (fault indicated by light flashing red) On/Off switch
4 Pressure gauge (bar) and temperature gauge (C)
Domestic hot water temperature selector (F24E Only) minimum setting approx. 38C up to maximum setting 60C.

Programmer (F24E Only).

The ECO setting is ideally suited for all the requirements of normal family use (showers, washing up etc.). The maximum setting should be reserved for occasional use when very hot water is required.

Lighting the boiler :

Heating temperature adjustment : 2

Make sure that:

The boiler is connected to the electrical supply. The gas service cock is open. The room thermostat is calling for heat (if fitted). Turn the On/Off switch 1 The boiler ON indicator 5 to ON ( I ) will illuminate green.
Winter: Set the control knob between 1 and 5 (Heating ON) Summer: Set the control knob to (Heating OFF)

Stop the boiler :

to OFF ( 0 ) the Turn the On/Off switch 1 electrical supply is OFF.
If a fault occurs (indicated by

Changing an Event

Select the event to be changed with the Prog. key. A new set of days may be selected with the Day key just as in initial programming. Hours and minutes can be changed with the h and m keys. Press Prog. or key to store the new programme.

Deleting an Event

To delete only one or a few events: Press Prog. key until the desired program is displayed. Press m key to :59 and press once more to blank out. Press h key to 11PM and press once more to blank out. key, display will flash for several seconds and then Press enter the Run Mode. Using the reset key will delete ALL events, the time of day, and day of the week.
SOLUTION: The ON or OFF was not entered as part of the program. ON or OFF must be selected.

1 Technical Data F24E

Heating
Heat input (max) NET Q Heat input (min) NET Q 26,94 kW 91,200 BTU/H

F18E SB

Heat input (max) NET Q Heat input (min) NET Q 21,9 kW 74,722 BTU/H
9,91 kW 33,820 BTU/H Heat output (max) NET P 23,6 kW 81,550 BTU/H Heat output (min) NET P 8,9 kW 30,370 BTU/H Efficiency - Sedbuk D 78,3% Maximum heating temperature 87 C Expansion vessel effective capacity 5 litres Expansion vessel charge pressure 0,5 bar Maximum system capacity at 75C 110 litres Safety valve, maximum service pressure 3 bar

Hot water

Heat input (max) NET Q Heat input (min) NET Q Heat output (max) NET P Heat output (min) NET P Maximum hot water temperature Minimum hot water temperature Specific flow rate (for 35C temp rise) Threshold flow rate Maximum supply pressure Minimum supply pressure 26,94 kW 91,200 BTU/H 9,91 kW 33,820 BTU/H 23,6 kW 81,550 BTU/H 8,9 kW 30,370 BTU/H 60 C 38 C 9,8 litres/min. 1,7 litres/min. 10 bar 0,5 bar
11 kW 37,532 BTU/H Heat output (max) GROSS P 19,8 kW 67,556 BTU/H Heat output (min) GROSS P 9,2 kW 31389 BTU/H Efficiency - Sedbuk D 78,8% Maximum heating temperature 87 C Expansion vessel effective capacity 5 litres Expansion vessel charge pressure 0,5 bar Maximum system capacity at 75C 110 litres Safety valve, maximum service pressure 3 bar

Combustion

Products outlet diameter Fresh air inlet diameter Combustion products values 60 mm 100 mm CO (30 ppm) CO2 (5,9%) NOx (76 ppm)

Electrical

Electrical supply Electrical rating Level of protection Fuse rating 230 V ~ 50Hz 122 W fused at 3A IPX4D 1,25mA
Products outlet diameter Fresh air inlet diameter Combustion products values 60 mm 100 mm CO (60 ppm) CO2 (6,7%) NOx (48ppm)

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

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.

4.1 Hard Water Areas

In areas where the water is 'hard', more than 200mg/litre, it is recommended that a proprietary scale reducer is fitted in the cold water supply to the boiler.

5 Boiler Schematic F24E

1 - Fan. 2 - Air pressure switch. 3 - Heat exchanger. 4 - Overheat thermostat. 5 - Combustion chamber. 6 - Expansion vessel. 7 - Flame sense electrode. 8 - Burner. 9 - Ignition electrode. 10 - Pump. 11 - Heating thermistor. 12 - Ignition unit. 13 - By-pass. 14 - Gas control valve. 15 - Loss of water sensor. 16 - Domestic heat exchanger 17 - 3 way valve 18 - Domestic water flow sensor 19 - Filter cold water inlet 20 - Filling system 21 - Discharge safety valve (3bar) 22 - Drain valve 23 - Heating filter

17mm Air duct cutting length L minus 90mm plus 17mm = cutting length Flue duct Air duct
Flue duct cutting length Air duct cutting length + 95mm = cutting length
25mm check dimension (cut end)

Diagram 10a.3

Horizontal Top flue system
The maximum permissible length (L) is 3.5 m. For flue systems up to 0.5 m length, the flue restrictor must be fitted (a) inside the fan outlet. For longer flue systems, the restrictor must not be fitted. For each 90 flue elbow used, (or two 45 elbows) the maximum permissible length (L) must be reduced by 1 metre.

FLUE RESTRICTOR

Gasket

Diagram 10a.4

11 Electrical Connection
WARNING: This appliance must be earthed. 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. All system components must be of an approved type. Electrical components have been tested to meet the equivalent requirements of the BEAB. Do not interrupt the mains supply with a time switch or programmer. 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 3mm 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.

11.1 Mains Cable

Important: If a replacement supply cable is required it must be purchased. Part No. S1008600.
11.2 Voltage Free External Controls
WARNING: UNDER NO CIRCUMSTANCES MUST ANY MAINS VOLTAGE BE APPLIED TO ANY OF THE TERMINALS ON THE VOLTAGE FREE HEATING CONTROLS CONNECTION TERMINAL. This boiler will operate continuously on heating, as supplied, if the wire link (E), fitted between the two terminals of the heating controls connection, is left in place, see diagram 11.1. External heating controls e.g. Room thermostat, should be fitted in accordance with the rules in force and as shown in the example, diagram 11.2.

RETAINING SLOTS

CONTROLS PANEL REAR COVER SECURING SCREW (3)
VOLTAGE FREE HEATING CONTROLS CONNECTION TERMINAL

WIRE LINK(E)

Diagram 11.1

Diagram 11.2

11.3 Mains Voltage External Controls
WARNING: UNDER NO CIRCUMSTANCES MUST ANY MAINS VOLTAGE BE APPLIED TO ANY OF THE TERMINALS ON THE VOLTAGE FREE HEATING CONTROLS CONNECTION TERMINAL. When mains voltage external controls are used, remove the MAINS VOLTAGE HEATING CONTROLS CONNECTION PLUG from the fittings pack and install on the control interface PCB as follows. Gain access to the control interface by unclipping the fascia panel and hinging forward, see diagram 11.3. Route the external heating controls cable (not supplied) and connect to the plug, see diagram 11.3. Insert plug onto controls interface PCB, see diagram 11.3. Close the fascia panel and remove the screws to open the rear cover of control panel, see diagram 11.1. Secure the external heating control cable in the strain relief, and thread the cable through rear of the control panel and out of the cables exit, see diagram 11.4. Close and secure rear cover of control panel. IMPORTANT: Remove the wire link from the voltage free heating controls connector terminal, see diagram 11.1. Connect external heating controls as diagram 11.5. External controls should be fitted in accordance with the rules in force.
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

PRODUCTS SAMPLING POINT Diagram 15.1
15.1 Products of combustion check
Note: To obtain a products of combustion reading, unscrew the left hand sampling point cap on the flue elbow, located on top of boiler, see diagram 15.1. Connect the analyser tube onto sampling point. Refer to the combustion product values in Section 1 Technical Data. Switch on the electrical supply and gas supply, then operate the boiler. On completion of the test switch off the electrical supply and the gas supply, remove analyser tube and replace sampling point cap.
15.2 Service Check and Preparation.
Isolate boiler from the gas and electrical supplies. (F24E Only) Drain the Domestic hot water circuit, refer to diagram 15.2. Drain the boiler, refer to diagram 15.2. On completion check all gas-carrying parts for soundness with leak detection fluid.
To Drain the Domestic hot water circuit (F24E Only)
Close boiler isolating valve (b). Turn on one or more hot water taps.

To Drain the boiler

Close isolating valves (a) and (c). Open the boiler drain valve (f).
COLD WATER INLET (F24E Only)

(c) (f)

BOILER DRAIN VALVE HEATING FLOW
DOMESTIC HOT WATER OUTLET (F24E Only)
GAS SERVICE COCK Diagram 15.2
Note: Isolating cocks water and gas are shown in the: OFF position

15.3 Front panel

Unscrew and remove the two retaining screws from the bottom of the front panel. Remove front panel by lifting up and forward.

15.4 Control panel

Lower forwards to gain access to lower part of boiler.
15.5 Sealed chamber cover
Unscrew and remove the two retaining screws from the sealed chamber cover, see diagram. 15.3. Lift cover up and off pins on top of boiler.
15.6 Side panels (for ease of access if available), refer to diagram 15.4
Unscrew and remove the two retaining screws from front of each side panel. Left hand side panel only disconnect the control panel retaining strap at the control panel. Unhook each panel from the front retaining tabs. Pull each panel forward from the rear retaining tabs to remove.

Air flow switch take-off.

Electrical contacts.

17 Wiring Diagram F24E
FAN g/y br b w OVERHEAT THERMOSTAT or w THERMISTOR CH WATER PRESSURE SENSOR b b w g THREE-WAY VALVE bk bk w p y g or gn CHASSIS EARTH w GAS CONTROL VALVE PUMP g/y AIR PRESSURE SWITCH bk IGNITION PLUG ELECTRODES IGNITOR UNIT

SENSE ELECTRODE

MAINS VOLTAGE HEATING CONTROLS PLUG
230V SWITCHED LIVE FROM OPTIONAL FROST STAT. 230V SWITCHED LIVE FROM HEATING CONTROLS.
REMOVE VOLTAGE FREE LINK FLOW SENSOR

CONTROLS INTERFACE

VOLTAGE FREE HEATING CONTROLS PLUG

b r gn

REMOVE THE LINK IF FITTING VOLTAGE FREE OR 230V EXTERNAL CONTROLS. IF THE LINK IS NOT REMOVED THE BOILER WILL RUN CONTINUOUSLY.

J10 J1 S1 J12

J13 H2 H5 H1
g/y br br b g/y b b br g/y

J2 FUSE 125mAT

CHASSIS EARTH
g/y w r b br ON/OFF SWITCH 230V~50Hz PERMANENT MAINS SUPPLY FUSED AT 3A
bk- BLACK w- WHITE g/y- GREEN/ YELLOW br bpgBROWN BLUE PINK GREY rorgnyRED ORANGE GREEN YELLOW

USER INTERFACE

17a Wiring Diagram F18E SB
FAN g/y br b w w GAS CONTROL VALVE bk WATER PRESSURE SENSOR THERMISTOR CH b b w g bk w p y g or gn IGNITOR UNIT PUMP CH g/y CHASSIS EARTH
AIR PRESSURE SWITCH SENSE ELECTRODE IGNITION ELECTRODES PLUG

REMOVE VOLTAGE FREE LINK

J15 J11
b br g/y b br CHASSIS EARTH g/y br b

NOT USED

r b br
g/y 230V~50Hz PERMANENT MAINS SUPPLY FUSED AT 3A

18 Replacement of Parts

To Drain the central heating circuit
Open drain valve fitted at the lowest point in the system. Allow air into the system by opening a radiator bleed screw or the boilers drain valve (f).
Close the isolating valves (a), (b) and (c). Open the boiler drain valve (f).
HEATING COLD WATER RETURN INLET (F24E Only)
Note: Isolating cocks water and gas are shown in the: OFF position Diagram 18.1

IMPORTANT INFORMATION

WARNING: Before commencing the replacement of any component, isolate appliance from electrical supply and turn off gas at service cock. Replacement of parts must be carried out by a competent person. When replacing components it may be necessary to renew sealing washers, gaskets and 'O' rings. If new ones are supplied with replacement components they must be used. All parts are replaced in reverse order to removal. If any gas-carrying components are disturbed, removed or replaced it will be necessary on completion of assembly to test for gas soundness and purge in accordance with the current issue of BS6891 or in IE, the current edition of I.S.813 "Domestic Gas Installations".
CENTRAL HEATING THERMISTOR

Diagram 18.2

Locate central heating thermistor on heating flow pipe on centre of boiler, see diagram 18.2. Unclip thermistor from pipe. Disconnect electrical connections from thermistor. Fit electrical connections to replacement thermistor and fit thermistor to pipe. The polarity is not important.
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.
18.8 Burner injectors, refer to diagram 18.5.

Diagram 18.8

PCB (CONTROL BOARD)

10021 10001

CONTROL BOARD COVER

Diagram 18.9

Lift to remove the heat exchanger taking, care not to damage the insulation.

230V CONTROLS BOARD

CONTROL PANEL F24E shown

USER INTERFACE BOARD

MAINS SWITCH Diagram 18.10 HEX HEAD SCREW (4 OFF) PUMP HEAD
18.16 User interface 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 connections from the user inter face board. Remove the two user inter face board retaining screws. Remove the user inter face board.
PUMP ELECTRICAL CONNECTION BOX
18.17 Mains switch, 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 connections from mains switch. Remove the mains switch.

Diagram 18.11

Unclip control panel user interface and hinge forward. Do not strain the cables. Disconnect the electrical connection from the programmer. Undo the two securing screws and remove the programmer.
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

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.