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

A B C D E

Heating return Cold water inlet Heating flow Domestic hot water flow Gas supply
THEMA F SB 18 E - THEMA F SB 23 E
Ignition module Heating temperature adjuster Temperature/pressure 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

Shy 131

Diagram 4

FIXING JIG

From left to right, the fixing jig comprises: A - Heating return with isolating valve (m). B - Cold water inlet with isolating valve (p). C - Heating flow with isolating valve (q), drain screw (r) and safety valve (s). D - Domestic hot water out. E - Gas service cock.

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 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
The commissioning and first firing of the boiler must only be done by a competent person. Gas installation It is recommended that any air is purged from the supply at the gas inlet test point on the left hand side of the gas valve, see diagram 20. Filling the system

Diagram 20

Open shut off valves (slot of screw corresponds to flow direction).
Undo, but do not remove, cap on automatic air vent on top of pump. Do not retighten cap.
Open the tap on the system filling loop and fill the system until the pressure indicated on the display is between 1 and 2 bar.

Ins 017a

Reg 007
Important: - If this procedure is not carried out properly, the boiler will go into safety lock-out until all of the air has been purged. - When venting air from boiler, do not touch the schrader valve on the expansion vessel, it is NOT a vent. - Before starting the boiler, turn the pump impellor to make sure it is free to move. Unscrew black cap on front of pump. Using screwdriver, push in pump spindle and turn pump impellor 3 to 4 times. DO NOT HIT SPINDLE. Replace black cap. Starting the boiler Before starting the boiler check that: - The gas meter tap is open. If using Butane or Propane, check that valve on storage cylinder or tank is open. - you have removed the two fan transist clips from fan.
- The boiler gas service cock is open. - The boiler is connected to the electrical supply and switched on. - The front casing is fitted. First starting up Following the instructions given in the 'User Instructions' set boiler to run in central heating mode. Set boiler thermostat for maximum temperature and check that any external controls, if fitted, are calling for heat. Allow the temperature to rise to the maximum value, with all radiator valves open. The temperature rise will cause release of the gases contained in the water of central heating system. - Gases driven towards the boiler will be automatically released through the automatic air vents. - Gases trapped at the highest point of the system must be released by bleeding the radiators.

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 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.

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
External controls (if fitted)

Internal control (clock)

Short out external controls connection on top of reversing valve. Does burner fire ?
Rectify wiring operation faults on external controls
Is there continuity across terminals 3 and 4 of clock ?
Remove leaos from boiler thermistor. Check its resistance according to thermistor value table. is thermistor ok ?
Is clock calling for heat ? Replace thermistor
Is wiring between clock and pcb connection cn7 ok ?

Replace clock

Replace main pcb

CHART 1

Open hot tap fully. Does burner fire ?

NO HOT WATER

(except SB models)

PUMP NOT RUNNING

Is there 240 v at pump ?

YES YES

With selector switch/thermostat NO in position and turner to maximum. Does burner fire for CH ? Refer to chart n2

Is pump jammed ?

Is there 240 v at terminal cn2 of PCB ?

Replace pump motor

Free pump
Is there at least 3 litres/min water flow at tap ?
Check mains water supply, water filter

Replace main PCB

Check operation of water valve diaphragm. Does reversing valve mechanism move when hot tap is opened ?

Replace diaphragm

CHART 3
Is there continuity across DHW microswitch and PCB connections cn 6.4 and cn 6.9 ?

Replace dhw microswitch

FAN NOT RUNNING
Is there 240 v at fan ? Is fan jammed ?
Remove leads from boiler thermistor. Check its resistance in accordance with thermistor value table. Is thermistor ok ?

Replace thermistor

Replace fan

CHART 4

CHART 2

Termistor Values

Temperature (C) nominal resistance () for NTC Temperature (C) nominal resistance () for NTC 50 3605

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 Fan Pump Spark generator Air pressure switch Main PCB (SB models) Main PCB (THEMA F 23 E) Part No. No. Description Part No. Control PCB (all models) 57277 Water valve diaphragm kit 52519 Microswitch assembly (THEMA F 23 E)51590 Temperature/pressure gauge 57278 Boiler Thermistor 57060 Overheat thermostat 51199

108198 B 06/98