ISOMAX F 28 E - Gas boiler SAUNIER DUVAL - Free user manual and instructions

USER MANUAL ISOMAX F 28 E SAUNIER DUVAL

Note! The boiler serial number is marked on the label attached to the inside ofthe drop down door Referto the ‘intoduction' section page 3 fora description ofthe basic functions ofthe boiler The 'Users' section describes how to safely operate the boiler USERS SECTION Introduction. Commissioning Controls & lighting Control options Draining … Servicing/maintenance . INSTALLATION SECTION Introduction. Technical data Dimensions … Heating system design Domestic hot water system design. Boiler schematic … Fixing jig …. Piping system installation Boiler location . Boiler installation . Flue installation … Electrical installation . Commissioning Safety devices Settings. SERVICING SECTION Routine cleaning and inspection …. Replacement of parts Boiler schematic Technical data . Schematic wiring diagram Faut finding Spare parts. Mandatory waming for CEE countries Maming: 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 isintended. If you se any exception to this rule, please contact your nearest Saunier Duval dealer. Thank you in advance for your assistance.

INTRODUCTION The ISOMAXF boilerisa wallmounted modulating combination boiler with electronic ignition provid- ing central heating and stored hot water. The boilerisofthe 12E+category for use with Natu- rRalGas(G20) asdistributed in the United Kingdom, or Butane (G30), Propane (G31) or Towns Gas (G 130) with the appropriate conversion kit. The boiler has a fan assisted balanced flue which both dischargesthe productsof combustion to and draws the combustion air from the outside of the room. The boileris suitable fortop outlet flue connection only but, can be fitted with horizontal flue, vertical flue or twin-pipe flue. Refer to flue catalogue for further details. Both the central heating and domestic hot water temperature are user adjustable from the boiler control panel. Domestic hot water demand always has priority overheating demand. The boiler is designed for us as part of a saled water central heating system with fully pumped circulation. The pump, expansion vessæl and asso- ciated safety devicesare allfitted within the boiler The boilercan be installed against either an exter- nal wall or on an adjacent inside wall, that is, the flue system will pass directly to the rearorto either side to the terminal fitted on the outside wallface. COMMISSIONING The installation must be camied out by a qualified registered person in accordance with the relevant requirements of The Building Regulations, The Wa- ter Byelaws, The Building Standards (Scotland) Regulations and any applicable local regulations. Thesæ instructions should be carefully followed for the safe and economical use of your boiler. Ancillary equipment À range of flue accessories are available includ- ing vertical flues, twin-pipe flues, bendsetc. For further information contact your supplier. Substances Hazardousto Health The adhesives and sealants used in this appliance are cured and give no known hazard in this state. INSULATION PADS/CERAMIC FIBRE, GLASSYARN, MINERAL WOOL These can cause imitation to skin, eyes and the respiratory tract. If you have a history of skin complaintsyou maybe susceptible to imitation. High dust levels are usual only ifthe material is broken. Nomal handing should not cause discomfort, but follow normal good hygiene and wash your hands before eating, drinking or going to the toilet. you do sufferimitation to the eyesorsevere imitation to the skin, seek medical attention. Gas safety (Installation and use) Regulations In yourinterests and that of gas safety, it isthe law that ALL gasappliancesare installed and serviced by a qualified registered person in accordance with the above regulations. Gasleak orfault Ifa gasleak or fault exists or is suspected, tum the boiler off and consult the local gas supply com- pany or yourinstallation/service company. Air in the heating system Persistent air in the heating system may indicate leaks in the system or corrosion taking place. Call your installation/Servicing company. Overheating safety In the event of a problem, the overheating safety devices cause safety shutdown of the boiler. If this happens, call your Installation/Servicing company. Boiler controls The control panel, located atthe lowerfrontofthe boiler casing, see diagram 1, allows the boiler to be started, shut down, controlled and monitored during use. Fue Do not obstruct the outside terminal of the boiler. - On/Offbutton - Summer/Winter mode selector - Hot watertemperature adjuster - Hot water set point display Graphic display - _ Heating temperature adjuster = Heating set point display -_ Display backight @ N QU BW N M Diagram 1

ler Lighting the b Make sure that . The boileris connected to the electrical supply. . The gas service cockisopen. Then follow the instructions below : @restre on/0f button (1) The pressure must be between 1 and 2 bar not, the system must be filed by a competent person. Hab 264 Setting to the WINTER po: (Heating +hot wate Pressthe mode button to slectthe wintersymbol The flame symbol appears when the boiler is running Illuminates when the boiler lights

The actualtemperature ofthe heating system Adijusting the hot water temperature Press +or- to adjust the maximum temperature ofthe hot water (38°C to 60°C) Visual indication of set temperature (3) Adijusting the heati mperature Press +or- to adjust the maximum temperature ofthe heating (38°C to 87°C) Visual indication of set temperature D obtain domestic hot water, open a hot water ap. Hot water always has priority over central heating.

CONTROL OPTIONS (a) Programmable room stat Part N° 40010, (b) Isocom combined boiler control & ISOCOM programmable rom stat part N° 85915. Diagram 2 DRAINING Protection against freezing Draining and filling Ifthe boileristo be out of use for any long perods during severe weather conditions, it is recom- mended thatthe whole system, including the boiler be drained to avoid the risk of freezing. Ifin doubt, consult your srvicing company. The ISOMAX hasa built in frost protection device that protectsthe boilerfrom freezing. fthe boileris to be left and there isa risk of frost, ensure that the gasand electrical suppliesare leftconnected.The frost protection device willlightthe boilerwhenthe temperature of the boiler water falls below 6°C. When the temperature reaches 16°C, the boiler stops. Note: This device works irespective of any room thermostat setting and will protect the complete heating system. Caution: The boileris installed as part of a sealed system which must only be drained and filed by a competent person. Heating safety valve CAUMON: A heating safety valve with a discharge pipe isfitted to this boiler. The valve MUST NOT BE TOUCHED except by a qualified registered person. Ifthe valve discharges atany time, switch the boileroff and isolate it from the electricalsupply. Contact yourinstallation/serv- ice company. Pressure/temperature relief valve CAUTION: À domestic hot water pressure relief valve, with a discharge pipe isfitted to this boiler. The valve MUST NOT BE TOUCHED except by a qualified registered person. Ifthe valve discharges atany time, switch the boileroff and isolate it from the electricalsupply. Contact yourinstallation/serv- ice company. SERVICING/MAINTENANCE T ensure the continued efficient and safe opera- tion of the boiler, it is rrcommended that it is checked and serviced at regularintervals. 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 orsolvent cleaners. Boiler casing CAUMON. Do not remove or adjust the casing in any way, as incorrect fitting may result in faulty operation. [fin doubt, consult yourinstallation/serv- ice company.

DIMENSIONS - the boileritself - the fixing jig - the flue system Weight: 71 kg

Diagram 5 The ISOMAX is delivered in three separate packages:

e The ISOMAX is compatible with any type of ins- tallation. e Heating surfaces may consist of radiators, convectors or fan assisted convectors. e The ISOMAX can be piped directly to an under floorheating system without the need fora mixing bottle. The maximum central heating flow temperature can be set to 53°C on the boiler printed circuit board during commissioning. e Pipe sectional areas shall be determined in ac- cordance with normal practices, using the output/ pressure curve (diagram 4). The distribution system shallbe calculated in accordance with the output requirements of the actual system, not the maximum output of the boiler However provision shallbe made to ensure sufficient flow so that the temperature difference between the flow and re- tum pipes be less than orequalto 20°C. The mini- mum flow is 400 I/h. e The piping system shall be routed so asto avoid any air pockets and facilitate permanent venting ofthe installation. Bleed fittings must be provided at every high point of the system and on all radia- tors. e The total volume ofwaterpermitted forthe heat- ing system depends, amongst other things, on the static head in the cold condition. The expansion vessæl on the boileris pressurised at 0,5 bar (corre- Sponding to a static head of 5 m w.g.) and allows a maximum system volume of 160 litresforan aver- age temperature of 75°C and a maximum service pressure of 3 bar Thispressure setting can be modi- fied at commissioning stage if the static head dif- fers. An additional expansion vessel can be fitted to the system if required, se diagram 8. e Provision shall be made for a drain valve at the lowest point of the system. e Where thermostatic radiatorvalvesare fitted, not all radiators must be fitted with this type of valve, and in particular where the room thermostat is in- stalled. e In the case of an existing installation, it is ESSEN- TAL that the system is thoroughly flushed prior to installing the new boiler. Hilling the system A filling device mustbe fitted to the system to initially fill the system and replace water lost during særvicing,see diagram 8.

e Copper tubing or plastic Hep,0 may be used for the domestic hot water system. Unnecessary pressure losses should be avoided. e Aflow restrictorlimiting the flow through the boiler to a maximum of 16 l/minisfitted to the boiler e The boiler will operate with a minimum supply pressure of 0,7 bar but under reduced flow rate. Best operating comfort will be obtained from a sup- ply pressure of 1 bar ‘Hard Mater Areas In areas where the water is ‘hard', more than 200mg/litre, itisrecommended that a proprietary sale reducerisfitted in the cold water supply to the boiler. BOILER SCHEMATIC

10 - Heating safety valve (3 bar)

11 - Main heat exchanger

17 - Domestic heat exchanger

19 - Heating expansion vessel

20 - Heating thermistor

21 - Overheat safety thermostat

24 - Domestic safety valve (6 bar)

25 - Lossof water sensor

26 - Domestic expansion vessel

27 - Pressure/temperature relief (7 bar)

28 - Domestic safety valve (10 bar)

- Heating flow x - Domestic hot water outlet OÙ EX ë E -Gas ÊÈ—È Ÿ Ni D1 - Discharge from HTG safety valves A B c DE ë D2 - Discharge from DHW safety valves D3 - Discharge from temp/press (to tundish) Diagram 6 (D: [p2)| [D3| Vale | Minimum} Minimum | Maximum | Resistance butktsæ| sz of | szæof | restance | created by None Picherge fom DHW dischare| dischage| alowed |eachelbow or y totundish| pipe D2 |expressd asa bend I from length of . tundih | straight pipe ie. no elbows I orbends Tundih I G12| 15mm| 22mm up to 9m 08m I 28mm | uptol8m 10m I 35mm | upto27m 14m T G3/4 | 22mm| 28mm | uptoom 10m . 35mm | uptol8m 14m 42mm | upto27m 17m = Guy G1 | 28mm| 35mm | uptoom 14m I 42mm | uptol8m 17m ; 54mm | upto27m 23m Diagram 63

FIXING JIG The fixing jig is made up, from left to right, as fol- lows: A- Heating retumfitting with isolating valve(v) and drain knob (u). B- Cold waterinlet fitting with isolating valve (m)and factory fitted flow regulator and filter (not shown). C- Heating flow fitting with isolating valve (q), drain knob (n and safety valve (10). D- Domestic hot water outlet fitting with safety valve (28). E- Gasfitting. Diagram 7

PIPING SYSTEM INSTALLATION

e Heating system connections- Pipe diam. 22mm e Hot watersystem connections- Pipe diam. 15mm e Gasconnection - Pipe diam. 22mm e Domestic safety valve connection - Pipe diam.15mm e Heating safety valve connection - Pipe diam. 15mm Water connection Connectthe copperconnections supplied, to the fixing jig fittings, see diagram 7. Connect the sys- tem pipework to the boiler observing the correct flow and return format as shown in diagram 8. There are two setsoftwo safety valvesfitted to this appliance. Two are located on the jig diagram 7, (10) heating safety valve 3 bar and (28) DHW safety valve 10bar The othertwo are located inside the boiler (diagram 6,) (27) pressure/temperature relief safety valve 7 bar/90°C, and (24) DHW safety valve 6 bar. Domestic fn 7 Additional water Thermostatic expansion Boiler mixing valve vessel {if required) Temperature adjustment É Pressure 1 reducing Ÿ ES valve (supplied) Thermostaticaly Boiler controlled "set temperature" = 1 hot water hot water Return Heating Filling device circuit control valve Drain point Sh 173a Diagram 8

PIPING SYSTEM INSTALLATION

Step. 1 The intemal safety valveshave beentee'd together and the discharge pipe run so that it exits at the right hand bottom of the boiler (diagram 6) (D2). The tundish (supplied) must be used with thisoutlet within the normal guidelinesand code of practice (diagram 6a). Step 2 Tee the domestic safety valve (diagram 7) (28) outlet to the heating safety valve (10) outlet together. You can either extend this pipe horizontally to the outside wall. WARNING, It must not discharge above an entrance or window or anytype of public accessarea, the discharge must be extend using no less than 15 mm o.d. pipe to discharge in a visible position outside the building, facing downard preferably over a drain. The pipe must have a continuous fall and be ruted to a position so that any discharge of water possibly steam, cannot create any danger to persons, damage to property or external electrical components and wiring. altematively : The discharge pipe can be tee'd into the otherdischarge pipe afterthe tundish (diagram

6) provided that it has a continuous fall and that

provisions are made forthe size of discharge pipe immediately afterthe tundish (see diagram 6a). Safety valve discharge Domestic hot water supply options Under normal circumstances, the domestic hot water storage temperature inside the boiler can be stored between 37 and 60° C. It is recommended thatthe boilerstorage temperature is set by the user to the maximum of 60°C - this will ensure a more plentiful supply of hot water. It may be desirable to provide hot water to separate outlets at different temperatures (for example, to provide a limited temperature to prevent the risk of scalding). © be able to do this, a thermostatic mixing valve is supplied with the Isomaxboiler (factory setto 43°C) and can be fitted during the installation procedure. There are 2 options for the domestic hot water supply : L- Piping the hot water supply without the use of the mixing valve to provide hot waterto alltapsat the same temperature.

2- Piping the hot water supply using the mixing

valve (supplied) to provide hot water at boilerhot water “set temperature” to one tap and thermostatically controlled hot water to another tap(s). D pipe the hotwatersupply using the mixing valve, referto diagram 8. This shows one outlet supplying hotwateratthe boilerhotwater"settemperature" and one hotwateroutlet at a temperature pre-set atthe mixing valve. The mixing valve can be set between 35 and 60°C. Itisrecommended thatthe valve is adjusted (and locked) by the installer to the desired temperature. The connections to the mixing valve are : H - Hot water supply from boiler C - Reduced cold water supply MIX -Thermostatically controlled outlet Maming : It isstrongly recommended thatthe cold water supply to the mixing valve is taken from the reduced side of the pressure reducing valve (supplied) Note 1 : The mixing valve is fitted with two in-line strainer one on the hot inlet and one on the cold inlet. For servicing details of these, refer to the sparate instructionssupplied with the mixing valve. Note 2 : The mixing valve incorporates a "rapid failsafe" device which will automatically close the valve to safety in the event of supply failure on either hot or cold water The discharge must be extended using notlessthan 22 m o.d. pipe, to discharge in a visible position outside the building, facing downward preferably overa drain. The pipe must have a continuousfalland be routed to a position so that any discharge of water possi- bly boiling orsteam, cannot create any dangerto persons, damage to property or extemal electri- cal components and wiring. Tighten all pipe con- nection joints. Gas connection e The supply from the govemed gasmetermustbe ofadequate size to provide a constant inlet work- ing pressure of 20 mbar (8 in w.g.). T avoid low gas pressure problems, it is recom- mended thatthe gassupplyisconnected using 22 mm pipe. e 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 yourinterests and that of gas safety, itisthe law thatALL gasappliancesare installed and serviced bya qualified registered person in accordance with the above regulations.

BOILER LOCATION Clearances The position of the boiler must be such thatthere is adequate space for særvicing. The recommended clearancesare: 20 mm either side of the boiler. 600 mm at the front of the boiler. 300 mm below the boiler. e Place template on wallin required position, mak- ing allowancesforthe necessary clearancesetc. Note: It ispermissible to installthe boilerwith smaller clearancesthan those quoted above PROVIDING thatadequate consideration isgiven for Servicing/ Repairsat a laterdate. fany doubtexists, contact the Saunier Duval Rchnical Helpline 01773 828400. e Mark the position of the holes forthe hanging bracket and jig. e Diill, plug and fixthe hanging bracket to the wall using suitable screws. e Checkthat the hanging bracketislevel. e Dill plug and fixthe fixing jig to the wall. e For horizontal flue system, mark the position for the flue hole as follows: Fue to rear ofboiler e Mark correct position of hole from template. Fue to side of boiler e Markthe horizontalcentre line forthe hole on the rear wall. Extend the horizontal centre line to the side wall and mark the vertical centre line of flue hole as shown in diagram 9. Cutting the flue hole e Making allowance forthe slope of the flue, cut hole in extemal wall, preferably using a core drill. For installations with intemal and extemal access use à 10 5 mm diametercore drill. Forinstallations with intemal accessonly use a 125 mm diameter core drill. Important When cutting the flue hole and when extending the flue centre line to a side wall, rememberthat the flue system must have a fall of about 35 mm Diagram 9 9 105 or 125 core drill-

ns 0902 per metre of flue DOWNWARD towards the termi- nal. There must NEVER be a downward incline to- wardsthe boiler Terminal position The minimum acceptable spacings from the ter- minalto obstructions and ventilation openingsare shown in diagram 10. The boiler must be installed so that the terminal is exposd to the external air. Should any doubt exist as to the permissible posi- tion of the terminal, contact the Saunier Duval Technical Helpline 01773 828400. Temminal guard Ifa terminalguard isrequired, a suitable guard can be obtained from your supplier Saunier Duval part number 85373. Cupboard or compartment ventilation The boilercan be fitted in a cupboard orcompart- ment without the need for permanent ventilation. Under a window Under an air vent Under a gutter Under a balcony From an adjacent window From an adjacent air vent … From vertical or horizontal air pipes. From an extemal comerofthe building From an intemal comerofthe building . From the ground or from anotherfloo Between two terminals vertic ally Between two terminals horizontally … Zzzr-Izonmonwp Diagram 10 Minimum dimensions (in mm) for the positioning of flue terminals

BOILER INSTALLATION Satutory requirements The installation of this boiler must be camied out by a qualified registered 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 edgesof sheet metal partsto avoid the possibility of personal injury. Installing the boiler Prorto starting work, the system must be thoroughly flushed using a propriety cleanser such as Sentinel X300to eliminate any foreign matterand contami- nation e.g. metal filings, solderparticles, oil, grease etc. Note. Solvent productscould cause damage to the system. e Engage boiler upper part onto the hanging bracket. e Fitthe washers between the boilerpipesand the inlet and outlet fittings on the fixing jig and con- nectthe varouscouplingsbetween the boilerand jig. FLUE INSTALLATION Pp outiet flue - kit 85090 The boiler is only suitable for top outlet flue connection. Rearflue systems The calculate the lenght when flueing to the rear measure e (diagram 11) plus 25 mm outerflue pipe and e plus 125 mm to inner pipe measurement. Calculation of cutting lengths when flueing to the right or left e Measure wall thickness e (mm), see diagram 11 For right hand applications e Measure distance from inside face ofwallto side of the boiler a (diagram 11) add 350 mm to outer pipe measurement and 445 mm to inner pipe mesurement. For left hand applications e Measure distance from inside face of wallto side of the boiler a (diagram 11) subtract 25 mm for outer pipe length and add 75 mm to inner pipe length measurement. e Refer to table 2 for cutting lengths of both inner and outer flue pipes for each of the various flue optionsavailable. Important All flue cutting lengths must be meas- ured from the terminal end of the flue pipes, see diagram 12. When the dimension X measured on site is greater than that given in table 2. Extensionswill be required asnecessary. Important All cutting lengths should be measured from the push fit joint end of the extension pipe. Do not leave any burrs or sharp edges on the cut endsofthe pipes. Note : maximum horizontal flue lenght without bendsis 3 m.

FLUE INSTALLATION Installation of flue assembly e Fit rubber sealing collar (F), see diagram 13, into groove at the outerend of pipe (A). e Fitouter pipe (A) into wall with groove to the out- side. e Pull pipe inwards to bring rubber sealing collar hard up against extemal wall, see diagram 14. e Fitintemal plastic flange (G)onto outerpipe. Push along the pipe untilengaged againstintemalwall. e From inside, insert inner pipe (B) into outer pipe. e Fit both ‘O’ rings (j) into the flue elbow (C), one at the inlet, one at the outlet. By necessity, they are a loose fit, apply a small amount of silicone gras to each ‘O’ ring when fitting. e Wrap sleeve (D) over outer pipe (A) and elbow (C) ensuring it isthe correct way round. e Take hold of the innerflue and push gently onto the elbow outlet taking care not to tear the ‘O' ring. e Open fixing collard (D) and locate between elbow and outer pipe (A). Close fixing jig. e Engage the two fixing clips (E) onto the colar onto (D) and press down to lock into position. Secure clips with screws provided. Important ffthe flue hasbeen cut, ensure thatthere are no bunsthat could damage the ‘O’ ring. e For flue systems less than 1,5 m long, leave the restrictor (a) fitted in the fan outlet, see diagram

e Remove the backing from the self adhesive gas- ket (H) and carefully fit gasket to base of flue el- bow. e Fit elbow onto boiler and secure with the four screws (1). Diagram 13 - Outerpipe - Inner pipe - Flue elbow - Fng collar. - Locking clips. - Btemal rubber saling collar - Intemal flange The flue kit 86285 is 1000 mm long and comprises: Pho 451 Diagram 14 R Concentric flue system flue systems, the restrictor must be removed. by 1 metre. Diagram 15 The maximum permissible length (L) for the concentric flue system is 3 m. For flue systems up to 1,5 m length, the restrictor (a) supplied fitted to the boiler inside the fan outlet, must be left in place. Forlonger Foreach 90° flue elbow used, (ortwo 45° elbows) the maximum permissible length (L) must be reduced Hab 249a

ELECTRICAL CONNECTION Maming. This boiler must be earthed All system components must be of an approved type. Connection ofthe whole electricalsystem and any heating system contrlisto the electricalsupply must be through a common isolator. Isolation should preferably be by a double pole switched fused spur box having a minimum con- tact separation of 3 mm on each pole. The fused spur box should be readily accessible and prefer- ably adjacent to the boiler It should be identified asto its use. A fused three pin plug and shuttered socket outlet may be used instead of a fused spurbox provided that: a) They are not used in a mom containing a fixed bath orshower b) Both the plug and socket comply with the cur- rent issue of BS1363. The mainselectrical supply must be maintained at alltimesin oderto provide domestic hot water Do notinteruptthe mainssupply with a time switch orprogrammer

WARNING: ON NO ACCOUNT MUST ANY EXTERNAL

VOLTAGE BE APPLIED TO ANY OF THE TERMINALS ON THE HEATING CONTROLS CONNECTION PLUG. Maming: This appliance must be wired in accord- ance with these instructions. Any fault arising from incorrect wiring cannot be putrightunderthe terms of the Saunier Duval guarantee. Extemal controls The ISOMAX boileris designed to operate at maxi- mum efficiency at all times, but will be most effi- cientand economicalwhen connected to a mom thermostat. A suitable room thermostat is available as an ac- cessory, Saunier Duval part number 40011 Please contact your supplier. Also available : For extra control or if the boiler isto be sited in a garage or utility mom an optional remote control unit with programmable momstatcanbe obtained part number 85915 (Isocom), diagram 2. This is a dual function unit (a) boiler control (same asboiler facia) (b) programmable room stat. Full fitting instructions supplied with the unit. Isocom only The boilerwill workforheating without a mom ther- mostat being connected provided that the wire link fitted between the two terminals of the con- nector (E) is left in place, see diagram 17. Altematively, a 230V rmomthemmostatcan be used but do not make any connection to the compen- sating resistor, see diagram 17. ON NO ACCOUNT must any electrical voltage be applied to any ofthe terminalsofthe extemalcon- trois plug. Note: For further information, see the building regulations 1991 - Conservation of Fuel and Power - 1995 edition - appendix G, Table 4b. The boiler is supplied with a mains lead at- tached. Connectthis to the electrical supply. Diagram 16 Leave link in place for no extemal controls. Diagram 17 IMPORTANT Mith voltage free room themmostat Without room thermostat

COMMISSIONING The commissioning and first firing of the boiler must Diagram 18 only be done by a qualifed registered person. Es Gasinstallation 1 Itis recommended that any airis purged from the Supply at the gasinlet test point on the gas valve, se diagram 18. Filling the system [1] Pressthe mains 'On/Off' button The waming light will iluminate The display will indicate 0 barpresure in the system Hab 260 Open the boilerisolating valves (v and q), the sbot ofthe screw corre- spondsto flow direction. Fully open valve mby tuming anti- clockwise. Undo cap on auto- matic air vent on top of pump and leave un- done.

Open filling device fitted previously, fill the system untilthe pressure indicated onthe display isbetween Land 2 bar Close filing device.

COMMISSIONING Bleed each radiatorto re- move the air re-tighten bleed screws. Leave the cap onthe pump auto airventopen. Open various hot water taps to bleed system. Make sure the display indicates a system pressure of between 1 and 2 bar Re-fill system as necessary. The pressure must be between 1 and 2bar Hab 265

COMMISSIONING Make sure that . The boileris connected to the electrical supply. . The gas service cockisopen. Then follow the instructions below : Pressthe On/Off button (1) The pressure must be between 1 and 2 bar If not, the system must be filed by a competent person. hting the boiler Setting to the WINTER po: (Heating +hotwate Press the mode button to slectthe wintersymbol The actualtemperature ofthe heating system Iluminates when the boiler lights Adjusting the heating tmperature Press +or- to adjust the maximum temperature ofthe heating (38°C to 87°C) Visual indication of set temperature Hab 264 e Adjust heating temperature to maximum. e Check that any extemal controls, if fitted, are calling forheat (set room thermostat to maximum). e Allow the temperature to rise to the maximum value, with all radiator valves open. The tempera- ture rise will cause release of the gases contained in the water of the central heating system. e Gassdriven towardsthe boilerwill be automati- cally released through the automatic air vent. e The gasestrapped atthe highest point ofthe sys- tem must be released by bleeding the radiators. On reaching maximum temperature, the boiler should be tumed off and the system drained as rapidly as possible whilst still hot. e Refill system to a pressure of between 1 and 2 barand vent asbefore. e Restart boilerand operate until a maximum tem- perature is reached. Shut down boiler and vent heating system. If necessary, top Up heating sys- tem and make sure that a pressure ofatleast1bar is indicated when system is COLD.

COMMISSIONING Setting the heating output The heating output can be set without the use ofa pressure gauge; proceed asfollows: e Pressthe display light button and keep pressed for 5 seconds, see diagram 20. Note:The boiler has now been put into ‘Service Mode, allowing certain adjustments to be made and diagnostic fault codesto be displayed. Refer to the 'Servicing Instructions for further details. The heating output, in KW, isshown on the lefthand side ofthe display, see diagram 21. e Remove the blanking plug from the front of the control panel to gain access to the heating ad- justing screw. e Adjust the heating output by tuming the screw clockwis to increase, anti-clockwise to decrease. e Refit blanking plug. Note: Adjustment of the heating output does not affect the domestic hot water output. For kW to Btu/hr conversion refer to table 5. Table 5 kW to Btu/hrconversion kW Bty/hr kW Bty/hr 10 34,120 20 68,240 12 40,940 22 75,060 14 47,710 24 81,890 16 54,590 26 88,710 18 61,420 28 95,540 kW Bty/hr 30 102,360

35 119,420 Setting the maximum heating tmperature The maximum heating temperature can be preset at commissioning stage to suit the type of heating system. For example, for use with underfloor heating, the maximum heating temperature can be setto 53°C. T adjust the maximum temperature, proceed as follows: . Remove the blanking plug (b) from the rear of the control panel to gain acessto selector switch SW1 (see diagram 22). Adjust toggles 1 and 2 to give the desired maxi- mum heating temperature, se diagram Note: To adjust the maximum heating temperature it is only necessary to change toggles 1 and 2. Do NOTtouch any othertoggles. . Refit blanking plug. Setting the heating output The heating output, in kW, is shown on the display. à Diagram 22 1=ON,2=ON + 53°C. Maximum. 12OFF, 2=OFF + 73°C. Maximum. 1=OFF 2=ON + 87°C. Maximum. Factory setting + 73°C. SAFETY DEVICES The ISOMAXincorporatesa visual display that indi- catesfault conditions, should they occur In the event of a fault, the display willindicate, by meansof pictogramsand/orletters and numbers, exactly in which area the fault lies. Should the boiler fail to operate during Commis- sioning, the most likely fault is that the gas supply to the boilerhasnot been tumed on orpurged suf- ficiently or that there is no pressure in the heating system. These are indicated as follows :

SAFETY DEVICES No gas supply + This will be indicated tres on the display as a [&—- pictogramofa spark. To rectify this, pro- ceed asfollows: < Switch off the boiler at the On/ Off push button. < Rectify the gas supply problem. . Restartthe boilerby pressing the On/Off button. Insufficient system pressure This will be indicated \ #7 || on the display as a = 02 — Pi flashing waming indi- .2 bar||mr cating the system pressure is low. TD rectify this the system must be re-filled, refer to ‘Commissioning'. Other faults Thesæ are indicated onthe display by a faultcode and a telephone symbol. Furtherinformation on the fault codescan be found in the ‘Servicing Instruc- tions’.

General safety devices Airflow rate safety device If an obstruction, even partial, of the flue occurs, for any reason whatsever the built in safety sys- tem of the boiler will tum the boiler OFF and the fan will continue to run. The boiler will be ready to operate when the fault hasbeen cleared. Overheat safety In case of boiler overheating, the overheat ther- mostat will tum the boiler off. The thermostat, lo- cated on the heat exchangerflow pipe, willneed to be manually reset. In case of power supply failure The boiler no longer operates. As son as power supply is restored, the boiler will be automatically restarted. Frost protection The ISOMAX has a builtin frost protection device that protectsthe boilerfrom freezing. Ifthe boileris to be left and there isa risk of frost, ensure thatthe gasand electrical suppliesare leftconnected.The frost protection device willlightthe boilerwhenthe temperature of the boiler water falls below 6°C. When the temperature reaches 16°C, the boiler stops. Note : This device works irespective of any room thermostat setting and will protect the complete heating system. Should it become necessary to change the gas type, a modification kit will be required. This modification must only be camied out by a suitably qualified engineer. Conversion natural Gas (G 20) to G30/G 31 Part No.

SETTINGS Gas valve setting Allboilersare tested and factory set during manu- facture. Should itbe necessary to reset a gasvalve, for example, after replacement, poceed as fol- lows: + Shut down boiler. Minimum setting < Remove one electrical connector from the modulating gas valve coil, see diagram 23. + Connect a suitable pressure gauge. < Setthe OFF/Summer/Winter switch to the ‘Sum- mer position. < Adjust the domestic hot water temperature ad- justerto maximum setting. < Remove the protective coverfrom the gasvalve adjuster . Tum nut ‘A’, se diagram 23: CLOCKWISE: D increase the pressure. ANTICLOCKWISE: D decrease the pressure. Maximum setting < Reconnect the electrical connector removed from the modulating gas valve coil. < Remove the protective coverfrom the gasvalve adjuster .Tum nut'B', see diagram 23: CLOCKWISE: D increase the pressure. ANTICLOCKWISE: D decrease the pressure. After adjustment, refit the cover to the gas valve adjuster Bypass The ISOMAX hasa built-in bypass. This must be ad- justed according to the requirementsofthe system, refer to the flow rate pressure curve (diagram 4). The boiler is supplied with the built-in bypassopen a half a tum. It is adjusted by tuming the bypass screw (a), see diagram 24. Tum the screw clock- wise to close the bypass.When using themmostatic radiator valves (TRV's) on all of the radiators, it is essential that a sparate, adjustable bypass of 15 mm minimum diameter is fitted between the flow and retum of the heating circuit, see diagram 8. Any bypass must be fitted before system controls. MODULATING COIL Electrical connection Reg 020 Diagram 24

T ensure the continued efficient and safe opera- tion of the boiler it is recommended that it is checked and srviced at regularintervals. The fre- quency of srvicing will depend upon the particu- lar installation conditions and usage, but in gen- erlonce a year should be enough. It is the law that any servicing is camied out by a qualified registered person. Service Check and Preparation. + Operate boilerand checkforanyfaultsthatneed to be put right. + Isolate boilerfromthe gasand electrical supplies. + On completion check all gas canying parts for soundness with leak detection fluid. + Remove boilercasing asfollows: Upper front panel + Remove the two front panel retaining brackets from the top of the boiler. + Remove panel by lifting up and forward. Sealed chamber cover + Unclip the toggle clip holding the sealed cham- bercover, see diagram. 1 + Lift cover up and off boiler. Front control panel + Lift control panel up and lower forwardsto gain accessto lower part of boiler Side panels + Unscrew and remove the four screws securing lower grille onto boiler. Unhook grille from rear of boiler and remove. + Removethree srewsfomfrontofeach side panel. + Unclip the toggle clipsscuring top ofeach panel. Lifteach panel up and then forward to remove. Combustion chamber cover + Unscrew the three screws securing combustion chamber coverto combustion chamber see dia- gram 2. + Remove combustion chambercoverfrom boiler + Undo, but do notremove, two bumersupportscrews atrearof bumerchamber Bumer + Undo main gas supply nut from bumer. + Pulloff the ignition and flame sense leadsfrom the gasvalve remove bumerfrom boilerby lifting up and pulling forwards from keyhole sots. Note: The washer between main bumer and main burner gas supply must be kept for use on reassembly. + Remove ignition and flame sens electodesfrom burmner. + Unscrew and remove injector bar retaining srewsand sparate injectorbarfrom bumer. + Examine and clean injectorsasnecessary. Note: DO NOTus a wire or sharp instrument on the holes. Clean bumerby washing in soapy water. Dry thor- oughly before re-fitting. Diagram 1 Heat exchanger + Disconnect power supply leads and earth lead from fan. + Unscrew and remove, two fan retaining screws at front edge of fan mounting plate. + Remove fan with mounting plate attached by pulling forwards out of boiler. + Remove air pressure switch sensing tube from sensing probe on flue hood. + Unscrew and remove screws securing flue hood to rearpanel. + Withdraw flue hood from boiler + Examine heat exchanger for any blockages or build up of deposits. + Clean heatexchangerwith soft brush orvacuum cleaner. Do not use any tool likely to damage painted finish of heat exc hanger. Reassembly of parts removed for servicing Allparts are replaced in revers orderto removal.

ue system + Check extemally to make sure that flue is not blocked + Inspect flue system to make sure that all fittings are secure. Operation of fan + Switch on electrical supply and tum on gas. + Light bumer by opening a hot watertap. + Without sealed chambercoverin place, bumer should be automatically prevented from lighting by airflow detection system. - Refit saled chamber cover + Checkthat fan operates when bumerlightsand stops when it goes out. Cold waterinlet filter Drain down hot water circuit of boiler only, as fol lows: + Close isolating valve/throttle (m) on cold water isolating cock, see diagram 3. Note: This valve isclosed when screwed fully clock- wise. + Openone ormore hotwatertapsto drain boiler circuit. + Undo connecting nut from cold waterinletcon- nection. + Clean and inspect filter replace if necessary. + With both filter and restrictor in place, recon- nect connecting pipe to inlet connection and tighten.

• Fully open isolating valve/throttle on cold wa- terinlet and check forleaks.

REPLACEMENT OF PARTS

Forreplacement ofthe following componentsit will be necessary to remove boilercasing panelsasde- scribed in ‘Routine Cleaning and Inspection’. MARNING: Before commencing the replacement of any component, isolate appliance from electri- cal supply and tum off gas at service cock. D replace domestic hot water themmistor + Locate domestic hotwaterthemmistoron hotwa- terflow pipe on right hand side of boileradjacent to gas valve. + Unclip thermistor from pipe. + Disconnect leads from thermistor. + Fitreplacement themmistor. + Fit leads to replacement thermistor the polarity is not important. D replace central heating thermistor + Locate centralheating themistoron heating flow pipe on centre of boiler + Unclip thermistor from pipe. + Disconnect leads from thermistor. + Fitreplacement themmistor. + Fit leads to replacement thermistor the polarity is not important. D replace sbrage vessel thermmistor Forthisoperation the boilermust be removed from the wall. + Drain down heating and hot water circuit of the boiler only, as follows: + Cloæ isolating valves(q) and (v) on centralheat- ing isolating cocks (A) and (C), see diagram 3. Note: These valvesare closed when sbotsare atright anglesto direction of flow. + Drain boiler by opening drain valves (n and (u), see diagram 3. Note: It is not necessary to drain down entire heat- ing system to carry out this work. + Close isolating valve/throttle (m) on cold water isolating cock, see diagram 3. Note: This valve isclosed when screwed fully clock- wise. + Open one ormore hotwatertapsto drain boiler circuit. + Disconnect flue system. + Disconnect boiler pipes onto fixing jig. + Disconnect mains cable and any extemal con- trols cables. + Remove boiler from wall. + From rear of boiler, disconnect domestic pipes from storage vessel. + Disconnect electrical connections from vessel. + Unclip vessel from boilerframe and remove from boiler. + Slide off plastic strap and separate two halvesof vessel insulation. + Locate thermistor at top of insulation. + Replace themmistor in same position as old ther- mistor.

• Refit vessel in reverse orderto removal. + Refit boiler onto fixing jig, tighten all connections ensuring that all saling washers are fitted before tightening. + Reconnect flue making sure that all joints are propery connected.

REPLACEMENT OF PARTS

+ Openisolating valveson flow and retum connec- tions, refill, vent and pressurise boiler. + Checkforleaks. + Reconnectallelectricalconnectionsand restore electrical supply. + Open gascock, operate boilerand re-checkall joints for soundness. D replace fan + Remove fan as described in ‘Routine Cleaning and Inspection’. + Fitreplacement fan in revers orderto removal. + Reconnectelectricalleads. D replace air pressure switch + Locate air pressure switch situated inside sealed chamber on top right hand side. + Remove air pressure switch tube from sensing probe on flue hood. + Disconnect air presure switch electrical connec- tions. + Undo screws on top of boiler securing air pres- sure switch to boiler and remove switch. + Pull sensing tube off switch. + Fit replacement switch to boiler in reverse order to removal, noting that pressure sensing tube fitsto left hand connection on switch. % replace domestic water flow sensor + Drain down hotwatercircuitofboileronlyasde- scibed previously. + Undo connecting nut from cold waterinlet con- nection. + Locate flow sensor on cold water inlet pipe to boilerinside controls area, see diagram 4. + Carefuly pull off electrical connector from flow sensor. + Pullout sotted metal clip scuring cold waterin- let pipe to flow sensor and carefully remove from sensor. + Pullout slotted metal clip securing flow sensorto pump mounting and carefully remove sensor from boiler. + Fit replacement sensor to boiler in reverse order to removal. D replace printed circuit board (PCB) + Gain accessto rearof control panel. + Unclip and remove extemal controls mains con- nection access cover + Unclip side clipsand hinge up control panelcover to gain accessto PCB, see diagram 5. + Carefully pull off electrical connectionsto PCB. + Unclip and lift out PCB. + Fitreplacement PCBin revers orderto removal. Note: 1) Make sure that PCB connections are fully pushed onto replacement PCB.

2) Setthe heating temperature option to the

REPLACEMENT OF PARTS

D replace pump + Drain down heating circuit of the boiler only, as described previously. Note: Itis not necessary to drain down entire heat- ing system to carry out this work. + Undo two fixing screwsand remove pump retain- ing bracket from front of pump. + Undo clips securing pump outlet hose connec- tion to pump. + Side hosæ along pipe to clear pump outlet. + Disconnect pump electrical connection from PCB. + Tansferautomatic airvent to replacement pump using new washers supplied. + Re-connect electrical connection to PCB. + Fit replacement pump in reverse order to re- moval. + Openisolating valveson flow and retum connec- tions, refill, vent and pressurise boiler. + Checkforleaks. D replace domestic hot water heat exchanger + Drain down heating and hot water circuits of boiler only as described previously. Note: ltisnot necessary to drain down entire heat- ing system to carry out this work. + Unscrew and remove cold waterinlet pipe from fixing jig to water flow sensor. + Supporting domestic heat exchanger unscrew and remove two screws securing it onto pump mounting and 3-way valve/bypass housing. + Remove heat exchanger from boiler. + Fitreplacementheatexchangerin revers order to removal using new sæals, supplied. Note: Heat exchanger mounting screws are offset to ensure correct fitting of replacement. D replace 3-way valve head + Locate 3- way valve in centre of lower controls area. + Remove electrical plug from valve head. + Pull out slotted metal clip from valve body and remove valve head from body. + Fit replacement valve head in reverse order to removal. Note :

1) When refiting clip, ensure that letters OK are as

shown in diagram 6. 2)it is not necessary to drain boilerto camy out this work. replace 3-way valve/bypass housing + Drain downheating and hotwatercicuitofboiler only as described previously. Note: It is not necessary to drain down entire heat- ing system to carry out this work. + Remove 3-way valve head as described previ- ously. + Remove domestic hotwaterheatexchangeras described previously. + Undo pipe connection from 3-way valve/bypass housing to primary heat exchanger see diagram 7. + Pull out slotted metal clips and remove bypass pipe. + Pull out slotted metal clip and remove domestic pipe from 3-way valve/bypass housing to storage vessel. + Undo pipe from 3-way valve/bypass housing to fixing jig. + From undemeath boiler undo two screws secur- ing 3-way valve/bypass housing and lift out of boiler. + Fit replacement 3-way valve/bypass housing in revers order to removal. D replace system pressure sensor + Drain down heating circuit of boiler only as de- scibed previously. Note: It is not necessary to drain down entire heat- ing system to carry out this work. + Locate system pressure sensor at front left hand side of boiler see diagram 8. + Remove electrical connections from sensor. + Pulloffslotted metal clip and remove sensorfrom boiler. + Fit replacement sensor in revers order to re- moval. D replace gas valve module + Locate gasvalve module attached to side ofgas valve.

REPLACEMENT OF PARTS

Diagram 9 + Remove screw securing cover onto gas valve module, see diagram 9. + Remove cover and disconnect multi-plug from module. + Disconnect ignition and flame sense leads from module. + Withdraw module from gas valve. + Fitreplacement module, ensuring itisof the cor- recttype forthe boiler, in reverse orderto removal. + Reconnect ignition and flame sense leads, the connections are uniquely sized to ensure correct replacement. + Reconnectmulti-plug onto replacement module. - Refitcoverensuring allsæaling grommetsare cor- rectly located in module body. D replace gas valve + Ensure that gas supply to boiler is tuned off at gascock. + Remove gas valve module as described previ- ously. + Disconnect electrical connections to gas valve modulating coil, see diagram 9. + Undo main gas supply nut from main bumer. Note: The washer must be kept for use on reassembly. + Undo main gasunion nutbetween gasvalve sup- ply pipe and gasinlet valve. Note: The washer must be kept for use on reassembly. + Disconnect plastic sensing pipe from gas valve to base of sealed chamber + Unscrew and remove screws securng gas valve bracket to boilerframe. + Withdraw gas valve assembly. + Using old gasvalve asa guide, transfergaspipes from old gas valve to replacement gas valve. + Fitreplacement gas valve into boiler. + Reconnectgaspipesin revers orderto removal. - Refitelectricalconnectionsin reverse orderto re- moval, the polarity of the wires to the modulating coil is not important. replace modulating coil + Ensure that gas supply to boiler is tuned off at gascock. + Disconnect electrical connections to gas valve modulating coil, see diagram 9. + Undo two screwssecuring modulating coilto gas valve and remove coil. + Fitreplacement coil in revers orderto removal. - Refitelectricalconnectionsin reverse orderto re- moval, the polarity of the wires to the modulating coil is not important. replace central heating safety valve Ifsafety valve sating isdamaged,itwillbe neces- sry to replace safety valve as a complete unit, repair is not possible. + Drain down heating circuit of boiler only as de- scribed previously. + Disconnect safety valve discharge pipe from safety valve. + Remove wire clip securing safety valve to fixing jig and remove safety valve, see diagram 10. + Fit replacement safety valve in revers order to removal. Note: Apply a small quantity of silicon grease to the safety valve 'O'ring priorto fitting. + Openisolating valveson flow and retum connec- tions, refill, vent and pressurise boiler + Checkforleaks. © replace sbrage vessel safety valve Ifsafety valve sating isdamaged,itwillbe neces- sry to replace safety valve as a complete unit, repair is not possible. + Drain down hotwatercircuit of boileronly asde- scribed previously. + Disconnect safety valve discharge pipe from safety valve. + Remove wire clip securing safety valve to fixing jig and remove safety valve, see diagram 10. + Fit replacement safety valve in revers order to removal. Note: Apply a small quantity of silicon grease to the safety valve 'O'ring priorto fitting. Diagram 10 Pla 214 + Openisolating valve on cold waterinletconnec- tion. + Checkforleaks. D replace heatexchanger + Drain down heating circuit of boiler only as de- scribed previously. Note: It is not necessary to drain down entire heat- ing system to carry out this work. + Remove combustion chamber cover, as de- scribed in ‘Routine Cleaning and Inspection. + Disconnect electrical connector from high limit thermostat.

REPLACEMENT OF PARTS

+ Remove dotted metalclipsfomheatexchangercon- nection pipes. + Undo nut æcuring pipe from heat exchanger to 3 way vale/bypashousng. + Swing pipe away from 3-way valve/bypass housing and pulldownto disengage fomheatexchangerpipe. + Pulldown pipe from pump to heatexchangerto dis- engage from heatexchanger pipe. + Side heat exchanger forwards and remove from boiler se diagram 1L + Fit replacement heat exchanger in revers order to removal. + Reconnectelectical connectorto high limitthemmo- sat. + Openislating valesonflow and retum connections, refil, vent and presuris boiler + Checkforkeaks

ml HUE Diagram 11 LE Lt ÉÉ + IE replace central heating expansion vessel Replacement of the expansion vessel is not possi- ble with the boileron the wall. Remove boilerfrom wallasdescribed in '"@ replace storage vessel thenmistor. + Undo pipe coupling on expansion vessel. + Supporting expansion vessel, unscrew and re- move screw securing expansion vesæl to boiler

• Lift vessel out of boiler. + Fit replacement vessl to boiler in reverse order to removal, ensuring that saling washerisfitted to pipe connection before tightening. + Ensure that expansion vessl charge pressure is

0.5 bar (7.5 psi) using a pressure gauge. If neces-

sary, increase pressure using a car or cycle tyre pump connected to the Schrader valve. + Refit boiler onto fixing jig, tighten allconnections ensuring that all sæaling washers are fitted before tightening. + Reconnect flue making sure that all joints are propery connected. + Openisolating valveson flow and retum connec- tions, refill, vent and pressurise boiler + Checkforleaks. + Reconnectallelectricalconnectionsand restore electrical supply. + Open gascock, operate boiler and re-checkall joints for soundness. replace high limit thermostat + Locate high limitthermostat on heating flow pipe on left hand side of boiler + Disonnectelectical connection from thermostat + Unclip thermostat from heating flow pipe. + Fit replacement thermostat in revers orderto re- moval.

• Refit connection to thermostat. % replace combustion chamber insulation

• Remove combustion chamber cover as de- scribed in ‘Routine Cleaning and Inspection’. + Remove heatexchangerasdescribed previously. + Remove fan and flue hood asdescribed in ‘Rou- tine Cleaning and Inspection. Front panel: *+ Lift front insulation panel free from retaining lugs on combustion chamber cover Rear panel: + Pull rar insulation panel free from retaining lug at earof combustion chamber by tilting forward. + Fit replacement insulation panels in revers or- derto removal

• Refit combustion chamber cover Side panels: + Pull out side panels. replace bumer + Remove bumer as described in 'Routine Clean- ing and Inspection’. Assmble replacement bumer supplied in parts, as follows: + Fit bumer injectors to bumer injector bar and tighten. Note: Make sure that injectorsize, marked oneach injector isthe same asthat given in ‘Rchnical Data” forthe type of gasbeing used. *+ Fitinjectorbarinto bumer æcure with retaining mds + Fit replacement bumerinto boiler in reverse or- derto removal. D replace bumerinjectors + Remove bumer as described in 'Routine Clean- ing and Inspection’. + Pull out injector barretaining rods and sparate injector bar from bumer + Unscrew and remove injectors from injectorbar. + Fit replacement injectors to injector bar and tighten. Note: Make sure that injectorsize, marked oneach injector isthe same asthat given in ‘Rchnical Data” forthe type of gasbeing used.

• Reassemble bumer and fit into boiler in reverse orderto removal. » replace ignition electode + Remove bumer as described in ‘Routine Clean- ing and Inspection’. + Undo and remove screw scurng electrode onto bumer. + Fitreplacementelectrode onto bumerin reverse orderto removal.

10 - Heating safety valve (3 bar)

11 - Main heat exchanger

17 - Domestic heat exchanger

19 -Heating expansion vessel

20 - Heating thermistor

21 - Overheat safety thermostat

22 - Flame sensorelectrode

24 - Domestic safety valve (6 bar)

25 - Loss of water sensor

6 - Domestic expansion vessel

27 - Pressure/temperature relief (7 bar)

28 - Domestic safety valve (10 bar)

V3V INTERFACE on/ off domestic water pump heating pump ignition card and flame control DA - _ignition demand @ - safety engaged Ham - ionisation contact three-way valve CH - heating COM - common SAN - hotwater INTERFACE - Userinterface Db - output detector Cp - water pressure sensor Vi - gasmechanism modulating valve J1 - connector for room temp. themostat TA - rom temperature themostat Diagram 14

FAULT FINDING Before trying to operate the boiler make sure that: + Allgas supply cocksare open and thatthe gas supply has been purged of air + The heating system pressure is at least 1 bar. + There isa permanent mains supply to the boiler. + The fuse on the PCBisintact. MARNING. Alwaysisolate the boiler from the elec- trical supply before camying out any electrical re- placement work. Always check for gas soundness after any service work. Should there be any doubt aboutthe voltage sup- ply to any ofthe components it is possible to cany out a simple electrical test to ensure all is opera- tional in that area. T cany out the electrical test, gain accessto the main Printed Circuit Board (PCB), asdescribed pre- viously, and measure the voltages according to table 1. ble 1 Voltage Measured value Measuring point 230 Volt 230 V AC Between terminals H8.1 and H8.2 24 Volt maximum 33V DC Between terminals B2.4 and B2.7 minimum 20V DC 15 Volt 15V +0.5V Between terminals B2.4 and B2.2 Display 5V +0.5V Between terminals B2.4 and B4.2 The ISOFAST hasan on-board fault diagnostic system. Should a faultoccuron the boiler the waming LED at the top of the user display # will illuminate and the LCD display will indicate the precise area where the faulthasoccured.

Sec 052 A fault code is displayed on the left hand side of the LCD display, whilst at the same time, the letters FF appear with a telephone symbol.

FAULT FINDING Themistor values The following table appliesto the central heating, domestic hotwaterand storage vesselthemmistors: Rmperature (°C) Resistance (Q) BRSRSAIRSAERSHENSHEUNO SPARE PARTS System pressure sensor The resistance of the sensor at various pressures is asfollows: between 280 Q and 320 Q between 195 Q and 220 Q between 93 ( and 143 Q When ordering spare parts, quote the part number and description, stating the appliance model number and serial number from the data badge. 1 Domestic hot waterthermistor 57213 2 entral heating thermistor 57215 3 Storage vessel thermistor 57250