Potthof & Co 28kw, 24kw, 33kw manual Gas Valve Fig, Expansion Vessel Fig

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Sensing Pipe

Power Lead

Earth Lead

Gas Feed

Elbow

Fig. 103

Venturi Inlet

Pipe

Gas Valve

Throttle

Adjustment Screw

14.0Changing Components

14.24Gas Valve (Fig. 103)

IMPORTANT: After replacing the valve the CO2 must be checked and adjusted as detailed in Section 15.0 Setting the Gas Valve. Only change the valve if a suitable calibrated combustion analyser is available, operated by a competent person - see section 13.1.

1.Turn the gas cock off and undo the nut on the gas feed elbow under the boiler.

2.Remove the screws securing the gas valve to the boiler bottom panel.

3.Pull off the power lead, earth lead and sensing pipe.

4.Undo the nut on the gas pipe at the gas/air inlet and the gas valve. Remove the pipe, taking care not to lose the sealing washers. Remove the valve.

5.Reassemble in reverse order, ensuring that all seals are in place and the injector is fitted.

NOTE: To assist the boiler to light prior to final setting, use a suitable hexagon key to wind out the Throttle adjustment screw until it is flush with the valve body, then turn the screw 4 full turns clockwise (Fig. 103a). If the boiler will not light, or the correct CO2 cannot be achieved contact the ‘heateam’ technical helpline.

Retaining Bracket

Boiler Chassis

Fig. 104

Fig. 103a

Expansion Vessel

Lock Nut

14.25Expansion Vessel (Fig. 104)

1.Drain the primary circuit and undo the nut on the vessel connection pipe.

2.Undo and remove the locknut securing the vessel spigot to the boiler air box.

3.Remove the bracket and vessel from the boiler.

4.Locate the retaining bracket on the upper flange of the vessel and fit to the boiler.

5.Reassemble in reverse order.

50© Baxi Heating UK Ltd 2012

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Contents Installation & Service Instructions Natural Gas Benchmark SchemeInstaller Notification Guidelines Scheme Members onlyCodes of Practice refer to the most recent version Important Installation, Commissioning, Service & RepairLegislation Preparation Safe Manual HandlingGeneral TechniqueContents Description Contents of PackIntroduction Expansion Vessel Automatic Air Vent General LayoutLayout Circulation Pump Drain Off PointFrost Protection Mode Central Heating Mode FigDomestic Hot Water Mode Fig Appliance OperationTechnical Data Gold Combi 24, 28 & 33 HE aDimensions and Fixings Central Heating Circuit System DetailsInformation BypassExpansion Vessel Central Heating only Safety Pressure Relief Valve FigSystem Filling and Pressurising Fig Hard Water Areas Domestic Hot Water Circuit FigShowers Clearances Figs Site RequirementsLocation At leastGas Supply Site RequirementVentilation of Compartments Electrical SupplyPer Metre PerPipe run Minimum Fall Run500mm min Minimum Fall50mm per Run Minimum fallBelow windows or openings on pitched roofs 2000 Plume Displacement KitFlue Likely flue positions requiring a flue terminal guardFlue Options Total equivalent length = +B+C+2x90BendsTotal Equivalent Length = +B+C+1x90Bend Telescopic Flue inc. elbow Flue AccessoriesKey Accessory Size Code No Air Duct Connection Flue Duct Connection Boiler Adaptor Twin Flue Duct AdaptorTwin Flue Connection Flue Trim Flue DimensionsFor Roof Terminals Terminal Guard FigPlume Displacement Plume Displacement Kit FigExample 28/33Determining Permissible Lengths Elbow30mm 50mmGeneral Fitting Notes Using a suitable bit e.g mm, drill through Elbow to allow the flue to be installed as shown60Ø extension piece. It must be secured using two Extension and outlet. Secure using two of the screwsFlushing InstallationUnpacking & Initial Preparation After considering the site requirementsFitting the Filling Loop Kit Condensate Drain see section Fitting the Safety Pressure Relief Discharge Pipe FigFitting The Boiler Tighten all the connectionsEnsure Elbow is fully engaged into Boiler Adaptor Fitting The FlueWall Thickness Flue Elbow Wall Thickness Waste FlueEnsure Extension is fully engaged into Boiler Adaptor Inner Flue Support Bracket25mm Extension Cut End Terminal Block Cover Cable Clamp Making The Electrical ConnectionsPreliminary Electrical Checks Commissioning the Boiler Selector Switch DisplayCommissioning Screw Pump Automatic Air VentCheck the Operational Working Gas Inlet Pressure Temperature Control Selector Switch DisplayTemperature Control Gas Pressure Test Point Gas Valve It is necessary to set the boiler to ‘Calibration Mode’Setting the Timer Case Front Panel Facia Panel CompletionCompletion Annual Servicing Inspection Servicing13 .1 Annual Servicing Electrode Position 10 ±1Spark and Sensing Electrodes Fig Changing ComponentsIgniter Fig Injector Fig Fan FigVenturi Fig Gasket Venturi Injector Cover Gas Inlet Pipe Fan CollectorExtension Piece Burner FigInsulation Fig DHW Temperature Sensor NTC Fig Central Heating Temperature Sensor NTC FigSafety Thermostat Fig Flue/Heat Exchanger Thermostat Sensor FigAutomatic Air Vent Fig Pump Head Only FigPump Complete Fig Pressure Relief Valve Fig Pressure Gauge FigsHall Effect Sensor Fig Diverter Valve Motor Unit & Assembly Fig Plate Heat Exchanger FigSelector Switch Fig 14.22 P.C.B. FigGas Valve Fig Expansion Vessel FigFlue Adaptor Test Point Plug Analyser Probe Setting the Gas ValveSetting the Gas Valve CO2 check CO2 should be 8.4% ± Reduce CO2Illustrated Wiring Diagram Electrical426 Short Parts ListShort Parts List 315316 311 404419 422 400 415Error Codes Fault FindingInitial Fault Finding Checks Reset position for 5 seconds Error 133 flashingGo to section ‘A’ Turn the selector switch to Pump runsOpen DHW tap fully Error 133 flashing Go to section ‘I’Turn Domestic Hot Water Close DHW tapFan jammed or faulty winding Replace PCB PCB X3 connector terminals 3Switch terminal Replace waterGas at burner Check wiring Viewing WindowReplace sensor or PCB E28 Replace gas valveReplace sensor Replace safety thermostatReplace PCB Is there 230V at Pages for Notes Pages for Notes GAS Boiler System Commissioning Checklist Service Record Potterton