Heating and hot water for the professionals

User Instructions

THEMA C
IN WARRANTY TECHNICAL HELPLINE

01773 828400

THIS IS A CAT II2H3+ APPLIANCE

01773 828100

USER INSTRUCTIONS THEMA C 23
Note! The boiler serial number is marked on the label attached to the front of these instructions. Refer to the 'Introduction' section for a description of the basic functions of the boiler.
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.. Page 2 - 3 Controls & lighting.. 3 Draining... 4 Servicing/maintenance.. 4

INTRODUCTION

The THEMA C 23 boiler is a wall mounted modulating combination boiler providing central heating and instantaneous 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. These instructions should be carefully followed for the safe and economical use of your boiler. 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. Bathroom fittings Any ancillary equipment such as mixing valves, showers etc. must be designed to operate at mains water pressure. Contact your local Water Authority for advice. Electrical supply WARNING: This boiler must be earthed. The boiler must be connected to a 230V 50Hz permanant supply. To connect a plug: The colours of three core flexible cable are: Brown - Live Blue - Neutral Green/yellow - Earth As the marking on your plug may not correspond with these colours, proceed as follows : The cable coloured blue must be connected to the terminal marked "N" or black. The cable coloured brown must be connected to the terminal marked "L" or red. The cable coloured green/yellow must be connected to the terminal marked "E", green or the earth symbol. Boiler location The boiler should have the following minimum clearances for maintenance purposes: 5mm on each side of boiler 300mm above boiler 250mm below boiler 450mm in front of boiler Mains failure In the event of failure of the electrical supply, the boiler will not operate. When the supply is restored, the boiler will return to normal operation.
Gas leak or fault If a gas leak or fault exists or is suspected, turn off the gas supply. Do not touch any electrical switches. Do not smoke. Consult the local gas supply company or your Installer/Service Provider. Air in the heating system Persistent air in the heating system may indicate leaks in the system or corrosion taking place. Call your Installer/Service Provider. Overheat safety In the event of a problem, the overheat safety devices cause safety shutdown of the boiler. If this happens, call your Installer/Service Provider. Boiler controls The control panel, located behind the pull down door at the lower front of the boiler casing, see diagram 1, allows the boiler to be started, shut down, controlled and monitored during use.
1 - On/Off switch 2 - Piezo ignition button 3 - Summer/Winter mode selector
4 - Hot water temperature adjuster 5 - Heating temperature adjuster

Diagram 1

CONTROLS AND LIGHTING

To light the boiler

Before starting the boiler check that: The gas meter tap is open. The boiler gas service cock is open. The boiler is connected to the electrical supply and turned on.
Setting to summer/Winter mode

Summer Domestic hot water only Winter Heating and hot water
1 - Push in and keep depressed
2 - Push in several times until the pilot has lit

Hab 257

Adjustment of domestic hot water temperature
Open a hot water tap. Turn the temperature adjuster until the desired hot water temperature is obtained. Hot water always has priority over central heating.
3 - Wait for 20 seconds after the pilot has lit
4 - Release button. The pilot should remain lit, if it doesn't, repeat operations 1 to 3
Adjustment of central heating temperature
Turn the temperature adjuster until the desired central heating temperature is obtained. Make sure that any external controls are calling for heat. The heating system will begin to heat up.
To stop the boiler Push OFF switch (0)

Hab 269

DRAINING
Protection against freezing The boiler has a built in frost protection device that protects the boiler from freezing. If the boiler is to be left for a short period and there is a risk of frost, ensure that the gas Diagram 2 and electrical supplies are left connected and that the Summer/ Winter switch is left in the position, see diag. 2. Note: This device works irrespective of any room thermostat setting and only protects the boiler. Always ensure that adequate frost protection is given to the entire system where necessary. If the boiler is to be out of use for any long periods during severe weather conditions, it is recommended that the whole system, including the boiler, be drained to avoid the risk of freezing. If in doubt, consult your Installer/Service Provider. Draining and filling Caution: The boiler is installed as part of a sealed system which must only be drained and filled by a competent person. Note: If there is persistent loss of system pressure, indicated by the pressure gauge, you must consult your Installer/Service Provider. Heating safety valve CAUTION: A safety valve with a discharge pipe is fitted to this boiler. The valve MUST NOT BE TOUCHED except by a competent person. If the valve discharges at any time, switch the boiler off and isolate it from the electrical supply. Contact your Installer/Service Provider.

SERVICING/MAINTENANCE

To ensure the continued efficient and safe operation of the boiler, it is recommended that it is checked and serviced at regular intervals. The frequency of servicing will depend upon the installation conditions and usage but, in general, once a year should be enough. Cleaning The boiler casing can be cleaned with a damp cloth followed by a dry cloth to polish. Do not use abrasive or solvent cleaners. Boiler casing CAUTION. Do not remove or adjust the casing in any way, as incorrect fitting may result in faulty operation. If in doubt, contact your Installer/Service Provider.

109452 B 07/98

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)

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

Ven 060b

Ins 012a

BOILER INSTALLATION
Statutory requirements The installation of this boiler must be carried out by a competent person in accordance with the relevant requirements of the current issue of: The Gas Safety (Installation and Use) Regulations The Building Regulations The local water company Byelaws The Building Standards Regulations (Scotland) The Health and Safety at Work Act Sheet metal parts WARNING. When installing or servicing this boiler, care should be taken when handling the edges of sheet metal parts to avoid the possibility of personal injury. Installing the boiler Prior to starting work, the system must be thoroughly flushed so as to eliminate any foreign bodies and contaminants such as filings, solder particles, oil, grease etc. Note. Solvent products could cause damage to the system. Note. If using a rear outlet flue system, follow the instructions in 'Rear outlet flue installation' section prior to hanging the boiler. Engage boiler upper part onto the hook, see diagram 9. Allow the boiler to seat down onto support plate, see diagram 10. Fit filter and washers, strictly adhering to the sequential order and directions shown on diagram 5. Connect the various couplings between the boiler and the connection plate.

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 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.

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 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
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