Datasheet | Main Multipoint BF Technical data
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Main Multipoint BF is a gas-fired water heater designed to provide hot water for domestic use. It offers precise temperature control, allowing you to set the desired water temperature between 25°C and 50°C. The device features a permanent pilot light for efficient ignition and a thermoelectric safety valve for added protection. Additionally, it has a built-in spout and integral tap kit, making it suitable for oversink installation.
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Bosch Thermotechnik WR 325 BF Gas Fired Multipoint Water Heater INSTALLATION AND SERVICING INSTRUCTIONS GC NUMBER 52 311 01 For your safety – if you smell gas: 1. Turn off the appliance 2. Open all windows and doors 3. Do not operate any electrical switches 4. Extinguish all naked flames 5. Contact the local Gas Region immediately This appliance conforms to European Standard EN 26. It is the law that all gas appliances are installed by competent persons. The following instructions should be read carefully as the manufacturer cannot be held responsible for any damage to property, persons or animals caused by incorrect installation or operation of the appliance. It is recommended that the appliance be serviced annually by a competent person or the local Gas Region. The Users Instructions should be handed to the user and the function and operation of the appliance explained. Contents 1. 2. 3. 4. 3. 6. 7. 8. 9. 10. 11. 12. 13. Installation Regulations.................................................Page 2 General Information ......................................................Page 2 Technical Data ................................................................Page 5 Siting the Appliance ......................................................Page 5 Siting the Flue Terminal ........................ ........................Page 5 Air Supply .......................................................................Page 6 Gas Supply ..................................... ................................Page 6 Installation ................ .....................................................Page 6 Commissioning ..............................................................Page 7 Inspection and Servicing ..............................................Page 8 Replacement of Parts ....................................................Page 9 Fault Finding ....................... ...........................................Page 10 Short Parts List ...................... ........................................Page 10 2.6 PRINCIPLE APPLIANCE COMPONENTS 1. Installation Regulations A low thermal capacity Gas to Water heat exchanger. A stainless steel main gas burner. A gas section. A water section. A thermoelectric safety valve. 1.1 Gas Safety (Installation and Use) Regulations 1984:- All gas appliances must be installed by a competent person in accordance with the above regulations. Failure to install appliances correctly could lead to prosecution. 1.2 The manufacturer’s notes must not be taken, in any way, as overriding statutory obligations. 1.3 The compliance with a British Standard does not, of itself, confer immunity from legal obligations. In particular the installation of this appliance must be in accordance with the relevant requirements of the Gas Safety (Installation and Use) Regulations 1984 (as amended), local Building Regulations, Building Standards (Scotland) (Consolidation), byelaws of the local Water Company and Health and Safety Document No. 635 (Electricity at Work Regulations 1989). It should be in accordance with the relevant recommendations of the following British Standards. BS 6798:1987 Specification for Installation of gas fired hot water boilers of rated input not exceeding 60 kW. BS 5546:1990 Installation of gas hot water supplies for domestic purposes. BS 5440:1:1990 Flues and ventilation for gas appliances of rated input not exceeding 60 kW: Flues. BS 5440:2:1989 Flues and ventilation for gas appliances of rated input not exceeding 60 kW: Air Supply. BS 6891:1988 Installation of low pressure gas pipework installations up to 28 mm (R1). 1.4 To ensure that the installation will perform to the highest standards, the system and components should conform to any other relevant British Standards in addition to those mentioned in the instructions. 2.7 PACKING The appliance and flue components are packed in separate cartons. 2.8 GENERAL INSTALLATION If the appliance is to be fitted into a compartment, the compartment must conform to the requirements of BS 6798:1987: Section 6. The specified ventilation openings made into a wall or compartment door must not be obstructed. Do not place anything on top of the appliance. The clearances specified for servicing must be maintained. 2.9 FLUE The appliance has a room-sealed balanced flue system to the rear. The standard flue assembly will accommodate a wall thickness of between 260 mm and 430 mm. The 10 digit code number for the standard flue assembly is 7 709 000 423. A short flue assembly is available and will accommodate a wall thickness of between 100 mm and 150 mm. The 10 digit code number for the short flue assembly is 7 709 000 425. An extended flue assembly is available and will accommodate a wall thickness of between 410 mm and 570 mm. The 10 digit code number for the extended flue assembly is 7 709 000 424. 2.10 FACILITY TO FIT A SPOUT AND INTEGRAL TAP KIT The appliance has the facility for a spout and integral tap kit to be fitted for oversink installation. If this type of installation is required, please order the following components as necessary: 2. General Information 2.1 This appliance is available for use with natural gas. When installing the appliance for use with natural gas, please check 10 digit number on carton to ensure that the correct appliance has been specified. The 10 digit number for a natural gas appliance is 7 702 340 006. 2.2 This appliance is available for use with LPG. When installing the appliance for use with LPG, please check 10 digit number on carton to ensure that the correct appliance has been specified. The 10 digit number for an LPG appliance is 7 702 440 007. 2.3 This appliance is not suitable for external installation. 2.4 The appliance is set to provide a maximum output of 21.4 kW and a minimum output of 7 kW. 2.5 The appliance has a permanent pilot. 2 Integral tap kit (incorporating hot and cold taps and handles) 7 709 000 406 Chrome plated swivel spout – 150 mm length 7 709 000 041 Chrome plated swivel spout – 250 mm length 7 709 000 042 Chrome plated swivel spout – 350 mm length 7 709 000 043 Fig. 1. Appliance water flow diagram KEY TO COMPONENTS 1. 2. 3. 4. Heat exchanger Pilot gas pipe Gas injector nozzle Measuring point 6. 7. 8. 9. 10. Valve spring Large gas valve Pilot gas filter Pilot gas valve Main gas valve 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. Pilot gas valve stem Pilot gas button Gas control slide Piezo igniter Gas filter Magnetic unit Slow-ignition valve Venturi Measuring point Gas inlet 3 21. 22. 23. 24. 25. 26. 27. 28. 29. Water strainer Hot water connecting pipe Cold water connecting pipe Volumetric water governor Water flow selector Relief valve Correcting screw for minimum water flow Diaphragm Blow-off valve Fig. 2. Appliance components KEY TO COMPONENTS 1. 2. 13. 14. *20. 22. 23. 25. Heat exchanger Pilot gas pipe Gas control slide Piezo igniter Gas inlet – downward facing Hot water connecting pipe – rear facing, left-hand side Cold water connecting pipe – rear facing, right-hand side Water flow selector 30. 31. 32. 33. 34. 35. 36. Flue hood Combustion chamber seal Main gas burner Pilot assembly Drain valve Gas section Water section * The gas inlet is situated towards the rear of the appliance. Do not confuse with the spout connection which is part of the brass housing. 4 3. Technical Data TABLE 2 – FLUE DETAILS TABLE 1 – GENERAL Natural Gas LPG Minimum rated output 7 kW 7 kW Maximum rated output 21.4 kW 21.4 kW Rated input 25.5 kW 25.5 kW 2.0 m3/hr Gas rate (maximum) 2.7 m3/hr Number of injectors 14 14 Injector diameter 1.10 mm 0.74 mm Pilot injector marking 5 49 Burner pressure 17 mbar 27 mbar Height 755 mm 755 mm Width 400 mm 400 mm Depth 220 mm 220 mm Dry weight 16 kg 16 kg Rc 1/2 Gas connection Rc 1/2 Hot/cold water connections 15 mm copper 15 mm copper Wall hole size – width Wall hole size – height Standard flue – minimum length Standard flue – maximum length Short flue – minimum length Short flue – maximum length Extended flue – minimum length Extended flue – maximum length 224 mm 326 mm 260 mm 430 mm 100 mm 150 mm 410 mm 570 mm (9 in.) (13 in.) (10.4 in.) (17.2 in.) (4 in.) (6 in.) (16.4 in.) (22.8 in.) TABLE 3 – PERFORMANCE Maximum cold water supply inlet pressure 12 bar (180 p.s.i.) Minimum cold water supply inlet pressure to operate the appliance 0.1 bar (1.5 p.s.i.) Minimum cold water supply inlet pressure for maximum domestic hot water flow 1.0 bar (15 p.s.i.) Domestic hot water delivery with temperature control knob fully anticlockwise 4 to 12.3 litres/minute at 25°C temperature rise Domestic hot water delivery with temperature control knob fully clockwise 2 to 6.1 litres/minute at 50°C temperature rise 4.9 No combustible surface must be within 75 mm of the casing. See BS 476:4. 4.10 The distance between the inner face of a cupboard door and the cabinet front should not be less than 75 mm. 4. Siting the Appliance 4.1 The appliance may be installed in any room which has an appropriate outside wall. 4.2 The appliance is not suitable for external installation. 4.3 The appliance does not require any special wall protection. 4.4 The wall must be capable of supporting the weight of the appliance. See Technical Data – Table 1. 4.5 If the appliance is to be fitted in a timber framed building, refer to the British Gas Publication “Guide for gas installations in timber framed housing”. 4.6 The following clearances must be available for installation and for servicing: Above In front Below Right hand side Left hand side 5. Siting the Flue Terminal See Fig. 3. 5.1 The flue must be installed as specified in BS 5440:Part 1. 5.2 The terminal must not cause an obstruction nor the discharge cause a nuisance. 5.3 If the terminal is fitted within 850 mm of a plastic or painted gutter or within 450 mm of painted eaves then an aluminium shield at least 750 mm long should be fitted to the underside of the gutter or painted surface. 5.4 If a terminal is fitted less than 2 metres above a surface to which people have access then a guard must be fitted. 5.5 The terminal guard must be evenly spaced about the flue terminal and fixed to the wall using plated screws. 5.6 In certain weather conditions a terminal may steam and siting where this could cause a nuisance should be avoided. 5.7 Take care to ensure that combustion products do not enter ventilated roof voids. 50 mm 600 mm 150 mm 10 mm 10 mm 4.7 The appliance can be installed in a cupboard used for airing clothes provided that the requirements of BS 6798 and BS 5440:2 are strictly followed. 4.8 The airing space must be separated from the appliance space by a perforated non-combustible partition. Expanded metal or rigid wire mesh are acceptable provided that the major dimension is less than 13 mm. See BS 6798:1987. 5 Fig. 3. Siting of the flue terminal. TERMINAL POSITION MINIMUM SITING DIMENSIONS FOR POSITIONING THE BALANCED FLUE TERMINAL A G D BC L HI L F A K F K E F J G M TOTAL LENGTH OF GAS SUPPLY PIPE (metres) 6. Air Supply 3 6.1 The appliance does not require a separate vent for combustion air. 6.2 Installations in cupboards or compartments require permanent vents for cooling purposes (one at high level and one at low level) either direct to outside air or to a room. Both vents must pass to the same room or be on the same wall to the outside air. 6.3 There must be sufficient clearance around the appliance to allow proper circulation of ventilation air. The clearances required for installation and servicing will normally be adequate for ventilation. 6.4 The minimum free areas required are given below. Position of air vents Air from the room Air direct from outside High Level 270 cm2. (42 in2.) 135 cm2. (21 in2) Low Level 2 270 cm . (42 in2.) MIN. DISTANCE A– directly below an openable window or other opening e.g. air brick. B– Below gutters, soil pipes or drain pipes. C– Below eaves. D– Below balconies or car port roof. E– From vertical drain pipes and soil pipes. F– From internal or external corners. G– Above ground, roof or balcony level. H– From a surface facing a terminal. I– From a terminal facing a terminal J– From an opening in a car port (e.g. door window) into dwelling. K– Vertically from a terminal on the same wall. L– Horizontally from a terminal on the same wall. M– From door, window or air vent (achieve where possible). 6 300 mm (12 in.) 300 mm (12 in.) 300 mm (12 in.) 600 mm (24 in.) 75 mm (3 in.) 600 mm (24 in.) 300 mm (12 in.) 600 mm (24 in.) 600 mm (24 in.) 1200 mm (47 in.) 1500 mm (60 in.) 300 mm (12 in.) 300 mm (12 in.) 9 Pipe Diameter (mm) – 4.6 9.4 15 22 28 Gas Discharge Rate (m3/h) 2.9 8.7 18.0 – 5.8 12.0 Note: Each fitting used in the gas line from the meter is equivalent to a length of straight pipe which must be added to the straight pipe length to give the total length. i.e. Elbow=0.5 metres, Tee=0.5 metres, 90˚ bend=0.3 metres. 8. Installation The installation must be carried out by competent persons. On delivery, check to make sure that the packaging has not been damaged. If there is evidence of damage, contact your supplier immediately. Check the 10 digit code number on the appliance carton to ensure that the correct appliance for the gas supply has been supplied. The code number for a natural gas appliance is 7 702 340 006. The code number for an LPG appliance is 7 702 440 007. Before commencing work, check that the correct flue kit has been supplied. There are three different telescopic flue kits available for various wall thicknesses. (See Technical Data – Table 2) 2 135 cm . (21 in2.) 6.5 Refer to BS 6798 and BS 5440:2 for additional information. 7. Gas Supply The appliance requires 2.7 m3/hr (95.4 ft3/hr) of gas. The gas meter and supply pipes must be capable of supplying this quantity of gas in addition to the demand from any other appliances being served. The following table gives an indication of limiting gas pipe lengths and the allowance to be made for fittings. Refer to BS 6891 for further information. The meter governor should deliver a dynamic pressure of 20 mbar (8 in w.g.) at the appliance. The complete installation, including the gas meter, must be tested for soundness and purged. Refer to BS 6891. A gas service cock must be fitted before each appliance, a gas service cock is supplied with every natural gas appliance (not supplied with LPG model). Important: If the 2.7m3/hr gas rate to the appliance cannot be reached, the specified hot water conditions will not be achieved. This could result in customer complaints. Always ensure that the gas supply is adequate. 8.1 FLUE KIT INSTALLATION Refer to flue kit installation instructions which are packed inside the flue kit carton. 8.2 APPLIANCE INSTALLATION (a) Unpack the appliance and take care to remove the installation kit which is packed on top of the polystyrene packing. The installation kit consists of the following: One gas service cock (not supplied with LPG model) One cold water isolating cock complete with fibre washer One hot water outlet complete with fibre washer Two 15 mm x 1/2 in. BSP female copper compression fittings 6 (b) Lay the appliance on its back and pull off the Temperature Control Knob. (c) Unscrew the plastic Temperature Control Knob housing. (d) Remove the four casing screw covers. Take out the four casing fixing screws and lift the casing clear. (e) Remove the collector hood from the appliance by slackening the two fixing screws and lifting the hood clear. (f) Lift the appliance on to the two mounting studs which are part of the flue kit assembly and fix in position using the two slotted nuts supplied. If required, there are fixing holes situated on the appliance back plate. Mark the fixing hole positions on the wall. Remove the appliance. Drill and plug the wall and then re-fit the appliance. (g) Push the flue gas connecting duct into the flue duct stub in the balanced flue assembly making sure it is fully home and resting against the stop protruding from the base of the stub duct. Ensure flue gas connecting duct has been cut to the correct size. See the Flue Kit Installation Instructions. (h) Re-fit the collector hood making sure that the flue duct spigot on the collector hood enters the flue duct connector. Tighten the two collector hood fixing screws. Connect the gas supply pipe to the appliance via a gas service cock. Note: The whole of the gas installation should be inspected and tested for soundness and purged in accordance with the recommendations of BS 6891. (i) Fit the two chrome water fittings supplied using fibre washers. The fitting which includes the stop valve should be fitted onto the rear right hand connection (viewed from the front) and the other fitting onto the rear left hand connection (viewed from the front). (j) Fit the two copper tails supplied to the chrome water fittings using a jointing compound suitable for use with potable water. (k) Connect the appliance to the incoming cold water supply via the fitting which includes the stop valve. (l) Connect the appliance to the domestic hot water remote draw off points via the other fitting. (m) At the bottom centre of the water section assembly there is an additional 1/2 in. male threaded joint which is the connecting thread for when a spout is connected for an oversink installation. See General Information paragraph 2.10. This outlet will not pass water until such time as an integral tap kit is installed on to the appliance and therefore, in a normal remote draw off installation, the 1/2 in. male threaded joint should be left unconnected and unplugged. (n) Turn on the water supply to the appliance. Open the stop valve on the inlet fitting to the appliance and then open the highest hot water tap in the installation. Allow water to pass in order to vent the system of air. Close the tap. Fig. 4. Inlet pressure test point Front should light. Wait 20 seconds and then release the centre button of the control slide. The pilot should remain alight. If the pilot is not established, repeat the operations until a flame is established. Note: On initial light up, or after prolonged shut-down, the establishment of the pilot may take several attempts due to the presence of air in the gas supply pipe. The pilot flame should envelope approximately 5 mm of the thermocouple head. (e) Move the control slide fully to the right. See Fig. 6. Fully open any hot water tap. The main burner should light. (f) Check the dynamic inlet gas pressure. The pressure for natural gas should be 20 mbar and the pressure for LPG should be 37 mbar. Fig. 5. Gas control slide – ignition position Piezo igniter Gas control slide in this position 9. Commissioning Fig. 6. Gas control slide – operating position Before commissioning the appliance, the whole gas installation must be purged and tested for gas soundness in accordance with the current edition of BS 6891. Important: Open all doors and windows. Extinguish naked lights and do not smoke while purging the gas line. (a) Ensure that the gas service cock in the gas inlet pipe is turned off. (b) Loosen screw A and connect a pressure gauge to the test point. See Fig. 4. (c) Turn on the gas service cock. (d) Move the gas control slide to the ignition position. See Fig. 5. Observe the pilot burner through the observation window. Press in the centre button of the control slide and hold depressed while pushing in the Piezo igniter button two or three times. The pilot Piezo igniter Gas control slide in this position 7 Fig. 7. Gas control slide – shut down position 10. Inspection and Servicing Piezo igniter To ensure continued efficient operation of the appliance, it is recommended that it is checked and serviced as necessary at regular intervals. The frequency of servicing will depend upon the particular installation conditions and usage but in general once a year should be adequate. It is the law that any service work must be carried out by a competent person such as British Gas or other Corgi registered personnel. Before commencing any service operation turn off the gas supply at the main gas service cock. Gas control slide in this position ACCESS FOR SERVICING Remove the front casing by removing the four plastic screw covers and then remove the four fixing screws. Pull off the Temperature Control Knob. Unscrew Temperature Control Knob housing. Lift the casing clear. If the pressure is not correct then check the gas supply to the appliance. If the pressure is correct, turn off the hot water tap and move the control slide to the off position. See Fig. 7. Turn off the gas service cock. Remove the pressure gauge and tighten screw A. See Fig. 4. (g) Loosen screw D and connect a pressure gauge to the test point. See Fig. 8. Re-light the appliance as described in paragraph 9 ( d and e). (h) Operate the appliance for at least 2 minutes then check that the burner pressure is as stated in Technical Data – Table 1. (i) Turn off the hot water tap. Close the gas service cock. Remove the pressure gauge and tighten screw D. (j) Re-fit the appliance casing using the four fixing screws. Fit the plastic Temperature Control Knob housing. Fit the Temperature Control Knob. Fit the four casing screw covers. (k) On completion of the commissioning and testing of the system, the installer should hand over the appliance to the user with reference to the following: 1. Give the Users Operating Instructions leaflet to the user. 2. Explain and demonstrate the lighting and shutdown procedures. 3. Advise the user of the precautions necessary to prevent damage to the system and to the building in the event of the system remaining inoperative during frost conditions. 4. Stress the importance of an annual service by a competent heating engineer. 10.1 Heat exchanger Remove the collector hood assembly by slackening the two retaining screws and pulling the hood out of the flue connector duct. If the connector duct comes away with the collector hood separate them and push the connector duct back into the stub in the balanced flue assembly making sure that it is fully home and resting against the two stops protruding from the sides of the stub duct. Inspect and clean the heat exchanger flueways if necessary. To remove the heat exchanger, isolate the appliance from the incoming cold supply and drain down the appliance via the drain cock fitted. Disconnect the heat exchanger flow and return pipes at the water section and the base of the combustion chamber. Remove the locknuts from the heat exchanger stubs and lift the heat exchanger clear. In hard water areas it may be necessary to descale the heat exchanger body. Either a proprietary brand of descaler or a solution of 10 parts of water to 1 part of hydrochloric acid should be used. Fill the heat exchanger with this solution and leave until the solution stops bubbling. Drain and thoroughly wash out the exchanger with clean water. Warning: Acid/water solutions must be used with extreme caution. Take care not to splash on to the skin or into the eyes. Wash any affected areas with large amounts of cold water and seek medical advice. 10.2 Pilot assembly Inspect the pilot injector and clean if necessary. Check the pilot burner and electrode are clean and undamaged. Clean or replace if necessary. Pull off the pilot filter and clean. Fig. 8. Gas pressure test point 10.3 Main burner Disconnect the pilot gas pipe and thermocouple at the gas valve and pull off the red cable from the Piezo unit. Disconnect the pilot gas pipe from the pilot burner and remove from the appliance complete with seal. Take care not to lose the pilot injector. Remove the two screws retaining the pilot bracket and lift the complete assembly clear. Undo the union connection below the burner. Lift the burner clear and remove. Inspect and clean the injectors if necessary. Inspect and clean the main burner bars if necessary. 10.4 Slow ignition valve Screw out the slow ignition valve (which is located on the right hand side of the valve above the water flow pipe into the heat exchanger. Item 17, Fig. 1. 8 The ball within the valve should move freely. Check by shaking. Check the O-ring and replace if necessary. Re-assemble in reverse order. 3. The seals around the igniter cable/thermocouple and pilot gas pipe are correctly seated in the combustion chamber base and the pilot injector has been fitted. 10.5 Re-assembling the appliance Re-assemble the appliance in reverse order ensuring the following: 1. The collector hood outlet duct correctly enters the flue connecting duct. 2. The washer in the main gas line union connection is correctly located. Turn on the gas supply at the main gas service cock and check for gas soundness in accordance with the current edition of BS 6891 while the appliance is running. Re-commission the appliance as detailed in Section 9. duct. If the flue connector duct comes away with the collector hood, separate them and push the connector duct back into the stub in the balanced flue assembly making sure that it is fully home and resting against the two stops protruding from the sides of the stub duct. Isolate the appliance from the incoming cold water supply and drain down the appliance via the fitted drain cock. Disconnect the heat exchanger inlet and outlet pipes at the water section and at the base of the combustion chamber. Remove the locknuts from the heat exchanger stubs and lift the heat exchanger clear. Replace the heat exchanger and re-assemble in reverse order. 11. Replacement of Parts It is the law that any service work must be carried out by a competent person such as British Gas or other Corgi registered personnel. Before commencing any service operation turn off the gas supply at the main gas service cock. 11.1 Pilot burner/injector Disconnect the pilot gas pipe and thermocouple at the gas valve and pull off the red cable from the Piezo unit. Disconnect the pilot gas pipe from the pilot burner and remove from the appliance complete with seal. Take care not to lose the pilot injector. Replace injector if necessary. Remove the two screws retaining the pilot bracket and lift the complete assembly clear complete with the red seal. Pull off the pilot filter. Undo the screw fixing the spark electrode /thermocouple retaining bar and lift these clear. Replace the pilot burner/bracket and re-assemble in reverse order. 11.5 Piezo unit Pull off the two wires from the rear of the unit, unscrew the plastic retaining nut on the control panel and push out the Piezo unit. Replace and re-assemble in reverse order. 11.6 Water section Isolate the appliance from the incoming cold water supply and drain down the appliance via the fitted drain cock. Disconnect the four union connections. Release the two screws between the water section and gas section and pull the water section clear. The diaphragm within the valve can be replaced by removing the three fixing screws holding the valve body together. The water filter fitted into the incoming cold water tapping can be cleaned or replaced by pulling it out. Re-assemble in reverse order. 11.2 Spark electrode/thermocouple Follow the instructions in Section 11.1 and replace the faulty component. 11.3 Main burner Disconnect the pilot gas pipe and thermocouple at the gas valve and pull off the red cable from the Piezo unit. Disconnect the pilot gas pipe from the pilot burner and remove from the appliance complete with seal. Take care not to lose the pilot injector. Remove the two screws retaining the pilot bracket and lift the complete assembly clear. Undo the union connection below the burner. Lift the burner clear of the union and push the front of the burner up into the combustion chamber so that it is standing vertically against the rear. Pull the rear of the burner forward so that the burner is now upside down and work out between the combustion chamber skirt and gas pipe. Replace the burner and re-assemble in reverse order taking care that the seals around the igniter cable/thermocouple and pilot gas pipe are correctly seated in the combustion chamber base and the pilot injector has been fitted. 11.7 Gas valve Remove the water section as described in Section 11.6. Disconnect the pilot gas pipe and thermocouple from the gas valve. Pull off the two cables from the rear of the Piezo unit. Release the main gas pipe union connection below the combustion chamber and lift the valve clear complete with the control panel. Remove the Piezo unit as described in Section 11.5. Remove the control facia by taking out the four fixing screws and lifting clear complete with slider knob. Prise out the slider bar and remove the two screws retaining the control frame and lift clear. Replace the gas valve and re-assemble in reverse order. 11.4 Heat exchanger Remove the collector hood assembly by slackening the two retaining screws and pulling the hood out of the flue connector 9 12. Fault Finding Problem Cause Incorrect water temperature Solution Incorrect gas rate Check the gas supply to appliance gas service cock Open the gas service cock Check the burner pressure Check the inlet pressure Incorrect water flow rate Noise Pilot flame will not stay alight Main burner will not light Explosive ignition Water section sticking or faulty Clean or replace Incoming supply valve closed Open supply valve Low water pressure Check the water pressure is above 0.1 bar Water section sticking or faulty Clean or replace Scale in heat exchanger Descale and service High gas rate Check the burner pressure Low water flow rate Check the water flow rate No gas supply Connect gas supply Gas service cock closed Open gas service cock Air in gas line Purge the line Pilot injector blocked Clean/replace the injector No spark Clean or replace the electrode, Piezo unit or cable Gas pressure low Check the inlet and burner pressure Gas service cock partially closed Open the gas service cock Low water rate Check the water rate Water section diaphragm faulty Replace the diaphragm Gas valve faulty Replace the gas valve Reduced pilot flame Clean or replace the pilot injector assembly Faulty slow ignition valve Replace the slow ignition valve 13. Short Parts List Part Manufacturer's Reference Pilot Burner 8 718 105 048 Pilot Injector 8 708 200 005 Thermocouple 8 747 202 082 Spark Electrode 8 708 107 002 Piezo Unit 8 748 108 023 Water Section 8 707 002 457 Diaphragm 8 700 503 051 Slow Ignition Valve 8 708 503 063 Gas Valve 8 707 011 028 Temperature Control Knob 8 702 000 111 Control Facia Plate 8 701 000 104 10 Additional Information 1. CE Certification 0064 MODEL CE NUMBER CATEGORIES WR325-1AD... WR325-1AV... CE 0085 AQ 0293 I3+ I2H TYPE C11 2. Symbols on Data Plate Pn Pmin Qn Qmin Pw Pwmin - Nominal useful output Minimum useful output Nominal heat input Minimum heat input Maximum service water pressure Minimum service water pressure Type: C11 - Natural draught appliances 11 Bosch Thermotechnik Worcester Heat Systems Limited, Cotswold Way, Warndon, Worcester WR4 9SW. Telephone: (01905) 754624. Fax: (01905) 754619. This booklet is accurate at the date of printing but will be superseded and should be disregarded if specifications and/or appearances are changed in the interests of continued improvement. All goods sold are subject to our official Conditions of Sale, a copy of which may be obtained on application. PUBLICATION 6 720 603 494, ISSUE 1 – JULY 1997
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