Baxi Potterton G.C.No 47 393 21 manual Replace safety thermostat, Replace PCB Is there 230V at

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18.0 Fault Finding

I

1.

2.

Check supply pressure at the gas valve:-

Minimum 17 mbar

Check and correct if necessary

1.The mechanical set of the gas valve (CO2 values - see instruction)

2.Flame sensing electrode and lead connections

3.Flame sensing electrode position

Flame current should be more than 0.5 μ A

YES

NO

Replace PCB

Replace flame sensing electrode

J

1.	Overheat thermostat operated or				NO			Allow to cool. Continuity	YES
	faulty, i.e. continuity across				NO			across thermostat terminals	YES		Replace safety thermostat
	faulty, i.e. continuity across							across thermostat terminals			Replace safety thermostat
	thermostat terminals							more than 1.5 ohm
	thermostat terminals							more than 1.5 ohm

	YES

				Replace PCB

K

	Is there 230V at:
						YES
1.
		Motor 3-way valve
		Motor 3-way valve						NO
2.

		PCB - X3 connector terminals
		PCB - X3 connector terminals
	5		& 6 central heating mode
	5		& 7 domestic hot water mode

YES

Change pump supply cable

Replace motor 3-way valve

Replace PCB

L

M

1.

1.

Fan connections correct at fan.

PCB - X401 connector terminals 5,6,7 & 8

Temperature sensors faulty. Cold resistance approximately 10kΩ @ 25° C (CH sensor)

20kΩ @ 25° C (Flue sensor)

(resistance reduces with increase in temp.)

YES	Replace fan

NO

Replace sensor

				YES
	2.	If pump is running the heat exchanger could be		YES		Replace heat exchanger
	2.	If pump is running the heat exchanger could be				Replace heat exchanger
		obstructed

© Baxi Heating UK Ltd 2011

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Contents Installation & Service Instructions 0086 Scheme Members only Installer Notification GuidelinesLegislation Important Installation, Commissioning, Service & RepairCodes of Practice refer to the most recent version Technique Safe Manual HandlingGeneral PreparationContents Introduction Contents of PackDescription Layout General LayoutAppliance Operation Frost Protection ModePump Protection Promax Combi 24, 28 Technical Data32.5 mm Condensate Drain 65 mm Dimensions and FixingsOrientation Tap RailBypass System DetailsInformation Central Heating CircuitExpansion Vessel Central Heating only System Filling and Pressurising FigPressure Relief Valve Fig Showers Domestic Hot Water Circuit FigHard Water Areas Location Site RequirementsAt Least 1.5 7.2 Clearances Figs Electrical Supply Site RequirementVentilation of Compartments Gas SupplyCondensate Drain Flue terminal guard FlueHorizontal Flues Each fitting to aid assemblyFlue Options Horizontal Flue SystemsApart Vertical FluesTwin & Vertical Flue Systems 120mm MinKey Accessory Size Code No Flue AccessoriesTelescopic Internal Flue Kit Twin Flue Connection Twin Flue Duct AdaptorAir Duct Connection Flue Duct Connection Boiler Adaptor Terminal Guard Fig Flue DimensionsFor Roof Terminals Flue TrimPlume Displacement Kit Fig Plume DisplacementMetres Ring Adaptor 5121368 28/33Determining Permissible Lengths Example30mm General Fitting NotesExtension and outlet. Secure using two of the screws Elbow to allow the flue to be installed as shown60Ø extension piece. It must be secured using two Using a suitable bit e.g mm, drill throughAfter considering the site requirements InstallationUnpacking & Initial Preparation FlushingTighten all the connections Fitting The BoilerFitting the Pressure Relief Discharge Pipe Fig Condensate Drain see sectionEnsure Elbow is fully Engaged into Boiler Fitting The FlueWall Thickness Waste Flue Elbow25mm Extension Cut End Inner Flue Support BracketEnsure Extension is fully engaged into Boiler Adaptor Preliminary Electrical Checks Making The Electrical ConnectionsTerminal Block Cover Cable Clamp Commissioning the Boiler CommissioningPressure Completion CompletionCase Front Panel Facia Panel Case Front Panel Facia Panel Securing Screws Servicing13 .1 Annual Servicing Annual Servicing InspectionBurner Sensing Electrode 10 ±1Viewing Window Igniter Fig Changing ComponentsSpark and Sensing Electrodes Fig Gasket Venturi Injector Cover Gas Inlet Pipe Fan Collector Fan FigVenturi Fig Injector FigInsulation Fig Burner FigBurner Gasket Extension Piece Flue/Heat Exchanger Thermostat Sensor Fig Central Heating Temperature Sensor NTC FigSafety Thermostat Fig DHW Temperature Sensor NTC FigPump Complete Fig Pump Head Only FigAutomatic Air Vent Fig Hall Effect Sensor Fig Pressure Gauge FigsPlate Heat Exchanger Fig Diverter Valve Motor Unit & Assembly Fig14.22 P.C.B. Fig Selector Switch FigGas Valve Fig Throttle Adjustment ScrewExpansion Vessel Fig Throttle Setting the Gas ValveSetting the Gas Valve CO2 check Flue Adaptor Test Point Plug Analyser ProbeElectrical Illustrated Wiring Diagram302 Short Parts ListShort Parts List 306Initial Fault Finding Checks Fault FindingError Codes Pump runs Error 133 flashingGo to section ‘A’ Turn the selector switch to Reset position for 5 seconds Open DHW tap fully Turn selector switch to Error 133 flashing Go to section ‘I’ Turn Domestic Hot WaterReplace water PCB X3 connector terminals 3Switch terminal Fan jammed or faulty winding Replace PCBReplace gas valve Check wiring Viewing WindowReplace sensor or PCB E28 Gas at burnerReplace PCB Is there 230V at Replace safety thermostatReplace sensor Page Page Condensing Boilers only Service Record Brooks House, Coventry Road, Warwick. CV34 4LL