Installation & Service Instructions Combi 24 HE These instructions include the Benchmark Commissioning Checklist and should be left with the user for safe keeping.
Natural Gas Main Combi 24 HE G.C.No 47 474 02 Building Regulations and the Benchmark Commissioning Checklist Building Regulations (England & Wales) require notification of the installation of a heating appliance to the relevant Local Authority Building Control Department. From 1 April 2005 this can be achieved via a Competent Persons Self Certification Scheme as an option to notifying the Local Authority directly.
Installer Notification Guidelines Choose Building Regulations Notification Route Competent Person's Self Certification Scheme Building Control Install and Commission this appliance to manufacturer's instructions Contact your relevant Local Authority Building Control (LABC) who will arrange an inspection or contact a government approved inspector Complete the Benchmark Checklist If you notify via the ‘Gas Safe Register’, the register will issue the Building Regulations certificate on members’ behalf
Legislation IMPORTANT - Installation, Commissioning, Service & Repair This appliance must be installed in accordance with the manufacturer’s instructions and the regulations in force. Read the instructions fully before installing or using the appliance. In GB, this must be carried out by a competent person as stated in the Gas Safety (Installation & Use) Regulations.
Safe Manual Handling General The following advice should be adhered to, from when first handling the boiler to the final stages of installation, and also during maintenance. Most injuries as a result of inappropriate handling and lifting are to the back, but all other parts of the body are vulnerable, particularly shoulders, arms and hands. Health & Safety is the responsibility of EVERYONE. There is no ‘safe’ limit for one man - each person has different capabilities.
1.0 Introduction 1.1 Case Front Panel Description 1. The Main Combi 24 HE is a fully automatic gas fired wall mounted condensing combination boiler. It is room sealed and fan assisted, and will serve central heating and mains fed domestic hot water. 2. The boiler is set to give a maximum output of 25.2 kW (condensing). 3. It is designed for use on Natural Gas (G20) and can be converted to use Propane. 4. The boiler is suitable for use only on fully pumped sealed heating systems.
2.0 General Layout 1 2.1 20 Layout 1. Air Pressure Switch 2. Expansion Vessel 3. Burner Manifold 4. Automatic Air Vent 5. DHW Plate Heat Exchanger 6. Circulation Pump 7. Drain Off Point 8. Safety Pressure Relief Valve 9. Optional Integral Timer Position 10. Central Heating System Pressure Gauge 16 11. Control PCB 15 12. Control Box 13. 3-Way Valve Assembly 14. Condensate Trap 15. Flame Sensing Electrode 16. Spark Electrode 17. Burner 18. Primary Heat Exchanger 19.
3.0 Appliance Operation 1 NOTE: All delay timers mentioned in 3.1 and 3.2 are overridden by domestic hot water demand. Central Heating Circuit 27 3.1 Central Heating Mode (Fig. 2) 2 3 4 7 26 5 6 8 2. The main burner ignites at low rate, then the gas valve controls the gas rate to maintain the heating temperature measured by the temperature sensor. 10 3. When the flow temperature exceeds the setting temperature, a 3 minute delay occurs before the burner relights automatically (anti-cycling).
4.0 Technical Data Appliance Type C12 Appliance Category C32 C52 CAT II 2H 3P Heat Input CH kW Max Min 24.8 10.6 Heat Output CH (Non-Condensing) Max Min kW 24 9.8 Heat Output CH (Condensing) Max Min kW 25.2 10.1 Heat Input DHW Max kW 24 Max Gas Rate m3/h Burner Pressure mbar IPX4D NOx Class 3 Condensate Drain Flue Terminal Dimensions (Natural Gas - G20) (After 10 mins) 2.
5.0 Dimensions and Fixings At Least 1.5° G Dimensions E A 780mm B 345mm C 450mm A D 116mm Ø Min.
6.0 System Details 6.1 Information 1. The Main Combi 24 HE Condensing Combination Boiler is ‘Water Byelaws Scheme - Approved Products’. To comply with the Water Byelaws your attention is drawn to the following installation requirements and notes (IRN). a) IRN 001 See text of entry for installation requirements and notes. b) IRN 302 Byelaw 14. 2. Reference to the WRc publications, ‘Water fittings and materials directory’ and ‘Water supply byelaws guide’ give full details of byelaws and the IRNs. 6.
6.0 System Details 6.5 System Filling and Pressurising 1. A filling point connection on the central heating return pipework must be provided to facilitate initial filling and pressurising and also any subsequent water loss replacement/refilling. Stop Valve Double Check Valve DHW Mains Inlet Fig. 4 Temporary Hose 2. There are connection points on the mains cold water inlet and central heating return isolating taps (Fig. 5) to which the optional filling loop kit (Part No. 248221) can be assembled.
6.0 System Details Other Tap Outlets 6.8 Expansion Vessel* Boiler Stop Tap Fig. 7 1. All DHW circuits, connections, fittings, etc. should be fully in accordance with relevant standards and water supply regulations. 2. Your attention is drawn to: for GB: Guidance G17 to G24 and recommendation R17 to R24 of the Water Regulations Guide. for IE: the current edition of I.S. 813. “domestic Gas Installations”. Check Valve* Pressure Reducer Valve* Domestic Hot Water Circuit (Fig. 7) To Hot Taps *See 6.
20mm/5mm Min 450mm 5mm Min 7.0 Site Requirements See * NOTE: 7.1 200mm Min 780mm Reset Flame Failure Power On 1 3 4 0 bar 200mm Min Fig. 8 1. The boiler may be fitted to any suitable wall with the flue passing through an outside wall or roof and discharging to atmosphere in a position permitting satisfactory removal of combustion products and providing an adequate air supply. The boiler should be fitted within the building unless otherwise protected by a suitable enclosure i.e.
7.0 Site Requirements 7.3 Ventilation of Compartments 1. Where the appliance is installed in a cupboard or compartment, no air vents are required. 2. BS 5440: Part 2 Clause 4.2 refers to room sealed appliances installed in compartments. The appliance will run sufficiently cool without ventilation. 7.4 Gas Supply 1. The gas installation should be in accordance with the relevant standards. In GB this is BS 6891. In IE this is the current edition of I.S. 813 “Domestic Gas Installations”. 2.
Termination to an internal soil and vent pipe 7.0 Site Requirements 7.6 Boiler Condensate Drain FAILURE TO INSTALL THE CONDENSATE DISCHARGE PIPEWORK CORRECTLY WILL AFFECT THE RELIABLE OPERATION OF THE BOILER 50mm per me 2.5° M inimum tre of fall The condensate discharge pipe MUST NOT RISE at any point along its length. There MUST be a fall of AT LEAST 2.5° (50mm per metre) along the entire run. pipe ru n 1. The condensate outlet terminates in a 1” BSP nut and seal for the connection of 21.
Terminal Position with Minimum Distance (Fig. 11) (mm) A1 Directly below an opening, air brick, opening windows, etc. B1 Above an opening, air brick, opening window etc. C1 Horizontally to an opening, air brick, opening window etc. D2 Below gutters, soil pipes or drain pipes. E2 Below eaves. F2 Below balconies or car port roof. G2 From a vertical drain pipe or soil pipe. H2 From an internal or external corner. I Above ground, roof or balcony level. J From a surface or boundary line facing a terminal.
8.0 Flue Options 8.1 Horizontal Flue Systems 1. The standard flue is suitable only for horizontal termination applications. Y X 2. All fittings should be fully engaged. The approximate engagement is 40mm. Apply soap solution to the seal on each fitting to aid assembly. 3. Maximum permissible equivalent flue lengths are:Horizontal Concentric 4 metres 4. Any additional “in line” bends in the flue system must be taken into consideration. Their equivalent lengths are:Concentric Pipes: 135° bend 0.
8.0 Flue Options Vertical Flues (Twin Pipe) 8.2 Twin & Vertical Flue Systems 1. Maximum permissible equivalent flue lengths are:Vertical Concentric Vertical Twin Pipe Y 4m 12m* * Both the air and flue duct can be up to 12 metres long each. X 2. Any additional “in line” bends in the flue system must be taken into consideration. Their equivalent lengths are:Concentric Pipes: 45° bend 0.5 metres 93° bend 1.0 metres Twin Flue Pipe 45° bend 0.25 metres 91.5° bend 0.
8.0 Flue Options 8.
8.0 Flue Options For Twin Flue Systems fit the adaptors as follows:- 8.4 Flue Duct Adaptor Blanking Plate Boiler Adaptor Flue Duct Adaptor 1. Engage the flue duct adaptor on the boiler adaptor, making sure that it is pushed down as far as possible. 8.5 Air duct adaptor 1. Undo the screws securing the blanking plate to the boiler top panel. Discard the plate. 2. There are three restrictor plates supplied in the kit.
8.0 Flue Options 8.6 1. In the case of a pitched roof 25 - 50 degrees, position the lead tile to replace/flash over existing roof tiling. Make an aperture in the roof suitable for the lower tube of the roof terminal and ensure the integrity of the roof cover is maintained. The adjustable plastic collar can either be positioned on the lead tile or the lower tube of the roof terminal prior to the final positioning of the vertical flue through the tile.
93° Elbow/Plume Outlet Assembly 9.0 Plume Displacement 9.1 60Ø Support Bracket O Ring Kit No 5118638 Content of kit 1 0.9m 60/100 Concentric Flue 1 1m 60 Dia Exhaust Flue Pipe 1 Adaptor 2 60 Dia Support Brackets 1 93° Elbow/Plume Outlet Assembly 1 Flexible Flue Trim 3 “O” Rings 1 ‘Jubilee Clip 1 Boiler Elbow 0.9 metres 60Ø Exhaust Flue Pipe 60Ø Support Bracket O Ring Fig. 14a Plume Displacement Kit (Fig. 14b) Flexible Flue Trim 1.
9.0 Plume Displacement 3 3 24 24 60 Ø Exhaust (metres) X 60 Ø Exhaust (metres) X 9.2 2 1 In the graph the solid line diagonal represents the relationship between the concentric flue assembly (and any extensions) and the 60Ø exhaust (and any extensions or additional bends).
9.0 Plume Displacement 9.3 General Fitting Notes 1. Cut a hole in the external wall which the concentric flue assembly will pass through. The hole should allow the flue to fall back to the boiler at an angle of 1.5° to 3°. 2. When completed the terminal must be at least 2 metres above ground level (Fig. 19). Min. 2 metres 3. Measure and cut to size the concentric assembly and any extensions that are being used. 4. Insert the concentric assembly through the hole from outside the building. 5.
9.0 Plume Displacement Plume Outlet Elbow 9.3 General Fitting Notes (cont.) 15. For aesthetic purposes it is permissible to route the 60Ø exhaust in an enclosed box, but the air inlet and plume outlet MUST remain in free air. 16. It is also possible to separate the plume outlet from the 93° elbow to allow the flue to be installed as shown in Fig. 25. 50 0m m Mi n. 17. To do this, first slacken the two screws retaining the plume outlet to the elbow, and remove the outlet (Fig. 26).
10.0 Installation 10.1 Initial Preparation The gas supply, gas type and pressure must be checked for suitability before connection (see Section 7.4). 1. After considering the site requirements (see Section 7.0) position the fixing template on the wall ensuring it is level both horizontally and vertically. 2. Mark the position of the two most suitable fixing slots for the wall plate and boiler lower fixing holes. It is preferable to use the horizontal fixing slots. 190mm 3.
10.0 Installation Wall Plate 10.4 Fitting The Boiler 1. Remove the sealing caps from the boiler connections. NOTE: A small amount of water may drain from the boiler once the caps are removed. Sealing Washers 2. Lift the boiler as indicated by the shaded areas. The boiler should be lifted by TWO PEOPLE. Engage the slots at the top rear of the boiler on the wall plate (Fig. 35) (see Safe Manual Handling page 5). 3.
10.0 Installation 10.6 m 5m 68 1. Connect the condensate drain using the 1” BSP nut and seal supplied. m 0m 10 Condensate Drain (see section 7.6) Ensure the discharge of condensate complies with any national or local regulations in force (see British Gas “Guidance Notes for the Installation of Domestic Gas Condensing Boilers”. Fig. 34 2. The condensate outlet terminates in a 1” BSP nut and seal for the connection of 21.
10.0 Installation 10.7 Waste Fitting the Flue (Cont) Y 5. Mark dimension ‘Y’ on the flue as shown (Fig. 37). Carefully cut the waste material from the flue, ensuring that the ducts are square and free from burrs. Fig. 37 6. The inner flue duct support bracket may be in the waste portion of the flue. In this case retrieve the bracket before discarding the waste. Flue 7. Take the inner flue support bracket (if not already fitted) and engage it over the flue duct.
10.0 Installation 10.8 Making The Electrical Connections To connect the mains input cable proceed as follows:1. Slacken the facia securing screws and lift the outercase panel so that its locating tabs are clear of the facia. Remove the panel. 2. Completely undo the screws securing the facia panel and hinge it down (Fig. 40). Control Box Cover Fig. 41 3. Remove the control box cover securing screws. Disengage the barbs on the control box from the cover. Remove the cover (Fig. 41). 4.
11.0 11.1 Screw Commissioning the Boiler Commissioning the Boiler 1. Reference should be made to BS:EN 12828 & 14336 when commissioning the boiler. 2. At the time of commissioning complete all relevant sections of the Benchmark Commissioning Checklist at the rear of this publication. Automatic Air Vent 3. Open the mains water supply to the boiler. 4. Open all hot water taps to purge the DHW system. 5.
11.0 Commissioning the Boiler OUT Pressure Test Point Sealing Screw 11.2 1. Turn on the gas and electrical supplies to the boiler and ensure that all external controls are calling for heat. Gas Valve MIN Checking the Burner Pressure 2. Set the temperature controls to maximum and the selector switch to the Off position (Fig. 51). 3. Slacken the pressure test point sealing screw on the gas valve and connect a pressure gauge (Fig. 48). 4. Undo the screws securing the inner door panel.
12.0 Case Front Panel 12.1 Completion Completion 1. Refit the case front panel and tighten the securing screws (Fig. 52). 2. Instruct the user in the operation of the boiler and system, explaining the operational sequence. 3. Carefully read and complete all sections of the Benchmark Commissioning Checklist at the rear of this publication that are relevant to the appliance and installation. These details will be required in the event of any warranty work.
13.0 Case Front Panel 13 .1 Servicing the Boiler Annual Servicing 1. For reasons of safety and economy, it is recommended that the boiler is serviced annually. Servicing must be performed by a competent person. 2. After servicing, complete the relevant Service Interval Record section of the Benchmark Commissioning Checklist at the rear of this publication. 3. Ensure that the boiler is cool. 4. Ensure that both the gas and electrical supplies to the boiler are isolated. 5.
Baffle Spring Clip Tab 13.0 13.1 Servicing the Boiler Annual Servicing (Cont) 10. Ease the front edge of the left hand baffle upwards, disengaging the spring clip. Disengage the tab on the baffle from the slot in the fan hood (Fig. 56). 11. Undo the screws securing the fan and hood to the appliance back panel. Draw the assembly forwards (Fig. 57). Fig. 56 12. Undo the screws securing the burner to the injector manifold.
14.0 Changing Components IMPORTANT: When changing components ensure that both the gas and electrical supplies to the boiler are isolated before any work is started. When the new component has been fitted turn the selector switch fully anticlockwise against the spring pressure to the ‘Reset’ position and hold for 2 seconds to reset the boiler before recommissioning. Pressure Switch Sensing Tubes See Section 13.1 “Annual Servicing” for removal of case panel, door etc. Pressure Switch Wires 14.1 Fig.
14.0 14.3 Changing Components Heat Exchanger (Fig. 64) 1. Remove the fan as described in section 14.1. 2. Drain the primary circuit. Prise the three pipe connecting clips off the joints in the flow and return pipes. Remove the heat exchanger return pipe. Pipe Connecting Clips Heat Exchanger Return Pipe 3. Lift the heat exchanger to disconnect the flow pipe joint. Withdraw it from the appliance, taking care not to damage the rear insulation piece. 4. Fit the new heat exchanger. 5.
14.0 Injector Manifold Inlet Elbow 14.5 Changing Components Injectors (Fig. 66) 1. Remove the burner as described in Section 14.4. Gasket Injector 2. Undo the screws securing the injector manifold to the inlet elbow and remove the manifold. 3. Unscrew and replace injectors as required and examine the sealing gasket, replacing as necessary. Reassemble in reverse order. 14.6 Burner Electrodes Fig. 66 Electrode Grommets Electrodes (Fig. 66) 1.
14.0 14.8 Changing Components Gas Valve (Fig. 68) 1. Undo the nut on the gas feed pipe under the boiler. Modulator Wires 2. Completely undo the securing screws and hinge the facia panel down. Ignition Lead Gas Valve 3. Disconnect the wires from the valve modulator and the ignition lead from the spark generator. Disconnect the pressure sensing pipe from the valve. Undo the screw securing the spark generator electrical plug to the valve and disconnect the plug. 4.
14.0 14.11 Changing Components Pump - Head Only (Fig. 71) 1. Drain the primary circuit and remove the socket head screws securing the pump head to the body and draw the head away. 2. Undo the screw on the pump wiring cover and remove the cover. Using a suitable flat bladed screw driver press the cable securing levers downwards to release each wire after noting their position. 3. A standard Grundfos 15-60 replacement head can now be fitted. Connect the wiring to the new head.
14.0 14.14 Changing Components Pressure Gauge (Figs. 74 & 75) 1. Drain the primary circuit and undo the nut on the pressure gauge capillary. 2. Remove the timer cover and ease the timer wiring aside. Undo the screws securing the gauge retaining bracket. Fig. 74 Pressure Gauge Capillary 3. Remove the bracket and gauge assembly. Depress the barbs on the side of the gauge and remove the retaining bracket. Gauge Retaining Bracket 4. Reassemble in reverse order. 14.15 Timer Cover Expansion Vessel (Fig.
14.0 14.17 Changing Components Pressure Relief Valve (Fig. 78) 1. Drain the primary circuit. 2. Disconnect the discharge pipe from the valve. Using a suitable hexagon key undo the grub screw sufficiently to release the valve. 3. Note the orientation of the valve, rotate it and withdraw it from the manifold. 4. Fit the new valve and ‘O’ ring seal and set to the previously noted orientation. Reassemble in reverse order. ‘O’ ring seal 14.18 P.C.B. (Fig. 80) 1.
14.0 Changing Components Plate Heat Exchanger 14.20 Plate Heat Exchanger (Fig. 67) 1. Drain the primary circuit. 2. While supporting the heat exchanger undo the screws securing it to the brass manifolds. 3. Withdraw the heat exchanger upwards and to the left of the gas valve, taking care not to damage any wires or controls. Rubber Seal Seals 4. There are four rubber seals between the manifolds and heat exchanger which may need replacement. Fig. 81 5. Ease the seals out of the manifold.
14.0 Microswitch / Bracket Central Heating Pressure Differential Valve 14.21 Sensing Pipe By-pass Pipe Diaphragm Changing Components Diverter Valve Assembly (Cont) Pressure Differential Valve (Fig. 84) 1. Remove the pressure differential valve as described above. 2. From the brass diverter manifold undo the nut on the heating flow pipe. Remove the screw securing the diverter manifold to the appliance lower bracket. Spring Clip 3.
14.0 Secondary Heat Exchanger 14.23 Changing Components Secondary Heat Exchanger (Fig. 87) 1. Drain the primary circuit Pipe Connecting Clip 2. Undo the four screws securing the right hand case panel. Remove the panel. Outer Drum Boiler Return Pipe Heat Exchanger Return Pipe Elbow Fig. 87 3. Prise the connecting clips from the heat exchanger return pipe and the boiler return pipe. Remove the pipes. 4. Remove the fan and hood assembly as described in Section 14.1 5.
15.
16.0 Fault Finding Carry out initial fault finding checks 1. Check that gas, water and electrical supplies are available at the boiler. Electrical supply = 230V ~ 50 Hz. CH water system pressurised to 0.5 bar when the boiler is cold. The preferred minimum gas pressure is 19.5mbar (natural gas), or 36mbar (propane). 2. Carry out electrical system checks, i.e. Ground Continuity, Resistance to Ground, Short Circuit and Polarity with a suitable meter.
16.0 Domestic Hot Water - Follow operational sequence Turn selector to neon illuminated NO Replace diaphragm Go to section ‘A’ YES YES Is mains water filter and differential assembly clean? YES NO DHW flow rate more than 2.5l/min. YES Primary water is diverted from CH system to DHW heat exchanger and flow microswitch operated NO YES Pump runs NO DHW flow valve diaphragm damaged NO YES Turn thermostat to max. Open DHW tap fully.
Fault Finding Solutions Sections A to F A 16.0 Fault Finding Is there 230V at: 1. Main terminals L and N 2. Main terminal fuse 3. B NO Check electrical supply YES Replace fuse NO Selector terminals a & b and a & 3. PCB - M1 connector terminals 9 & 10 neon illuminated Check wiring Replace selector NO Is there 230V at: 1. Pump 2. PCB - M1 connector terminals 8 & 15 NO If pump jammed, release Replace pump NO Replace PCB YES Change pump supply cable C NO 1. CH system pressure 0.
Fault Finding Solutions Sections G to L G 1. 2. 16.0 Check the burner setting pressure of the gas valve (see Section 11.2 of Commissioning) Voltage at modulating coil of gas valve is: Max. burner press.approx 9V DC (13V DC LPG) Min. burner press.approx 1V DC Current at modulating coil of gas valve is: (Use an instrument with average function for this measure) 30 ÷ 230 mA DC (45 ÷ 310 mA DC LPG) H I Fault Finding Check and correct if necessary 1. Ignition electrode and lead 2. Electrode connection 3.
17.0 17.0 Fault Indication Display Fault Indication Display 1. The boiler has three neon indicators. The upper two function as boiler on and fault indicators. A Off Fast Flashing (2 every second) On Burner On 2. Depending on the nature of the fault the upper two neons will illuminate, go off or flash. Flame Failure Power On 3. There are five possible combinations, each indicating one or more fault conditions. These are described below.
18.0 Short Parts List Short Parts List 44 140 22 131 135 333 63 Key No. G.C. No. 23 Fan 5112627 23 Pressure Switch 5137532 32 Heat Exchanger 5112431 41 Burner 5112770 44 E66 402 Injector - 1.18 NG 248210 59 E66 408 Electrode Lead 248037 63 E66 411 Spark or Sensing Electrode 247384 Pump 248042 101 E66 432 Hydraulic Outlet Assy. 248061 102 E66 434 Valve - 3 Way Assy. 248062 103 343 619 Pressure Differential Assy. 248063 131 135 41 Manufacturers Part No.
Failure to install and commission according to the manufacturer’s instructions and complete this Benchmark Commissioning Checklist will invalidate the warranty. This does not affect the customer’s statutory rights.
Service Record It is recommended that your heating system is serviced regularly and that the appropriate Service Interval Record is completed. Service Provider Before completing the appropriate Service Record below, please ensure you have carried out the service as described in the manufacturer’s instructions. Always use the manufacturer’s specified spare part when replacing controls. Service 1 Date: Service 2 Date: Engineer Name: Engineer Name: Company Name: Company Name: Telephone No.
All descriptions and illustrations provided in this leaflet have been carefully prepared but we reserve the right to make changes and improvements in our products which may affect the accuracy of the information contained in this leaflet. All goods are sold subject to our standard Conditions of Sale which are available on request. MAIN A Tra din g Di v i s i o n o f B ax i H e ating U K L td ( 3879156) Brooks House, Coventry Road, Warwick.
