Replace safety thermostat, Replace sensor | Potthof & Co 28kw, 24kw

18.0 Fault Finding

I

1.

2.

Check that the supply pressure at the test point on the gas valve is a MINIMUM of 17mbar

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 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.	Fan connections correct at fan.
	Fan connections correct at fan.
	PCB - X401 connector terminals 5,6,7 & 8

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

20kí @ 25° C (Flue sensor)

(resistance reduces with increase in temp.)

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

YES	Replace fan

NO

Replace sensor

YES	Replace heat exchanger

© Baxi Heating UK Ltd 2012

59

Image 59

Potthof & Co 28kw, 24kw, 33kw manual Replace safety thermostat, Replace PCB Is there 230V at, Replace sensor

Contents

Installation & Service Instructions Benchmark Scheme Natural Gas Scheme Members only Installer Notification Guidelines Codes of Practice refer to the most recent version Important Installation, Commissioning, Service & RepairLegislation Technique Safe Manual HandlingGeneral Preparation Contents Description Contents of PackIntroduction Circulation Pump Drain Off Point General LayoutLayout Expansion Vessel Automatic Air Vent Appliance Operation Central Heating Mode FigDomestic Hot Water Mode Fig Frost Protection Mode Gold Combi 24, 28 & 33 HE a Technical Data Dimensions and Fixings Bypass System DetailsInformation Central Heating Circuit Expansion Vessel Central Heating only Safety Pressure Relief Valve FigSystem Filling and Pressurising Fig Hard Water Areas Domestic Hot Water Circuit FigShowers At least Site RequirementsLocation Clearances Figs Electrical Supply Site RequirementVentilation of Compartments Gas Supply Run PerPipe run Minimum Fall Per Metre 500mm min Minimum Fall50mm per Minimum fall Run Likely flue positions requiring a flue terminal guard Plume Displacement KitFlue Below windows or openings on pitched roofs 2000 Total equivalent length = +B+C+2x90Bends Flue Options Total 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 Terminal Guard Fig Flue DimensionsFor Roof Terminals Flue Trim Plume Displacement Kit Fig Plume Displacement Elbow 28/33Determining Permissible Lengths Example 30mm 50mmGeneral Fitting Notes Extension 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 through After considering the site requirements InstallationUnpacking & Initial Preparation Flushing Fitting the Filling Loop Kit Tighten all the connections Fitting the Safety Pressure Relief Discharge Pipe FigFitting The Boiler Condensate Drain see section Wall Thickness Waste Flue Fitting The FlueWall Thickness Flue Elbow Ensure Elbow is fully engaged into Boiler Adaptor Ensure 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 Screw Pump Automatic Air Vent Selector Switch DisplayCommissioning Commissioning the Boiler It is necessary to set the boiler to ‘Calibration Mode’ Temperature Control Selector Switch DisplayTemperature Control Gas Pressure Test Point Gas Valve Check the Operational Working Gas Inlet Pressure Setting the Timer Case Front Panel Facia Panel CompletionCompletion Annual Servicing Inspection Servicing13 .1 Annual Servicing 10 ±1 Electrode Position Spark and Sensing Electrodes Fig Changing ComponentsIgniter Fig Gasket Venturi Injector Cover Gas Inlet Pipe Fan Collector Fan FigVenturi Fig Injector Fig Extension Piece Burner FigInsulation Fig Flue/Heat Exchanger Thermostat Sensor Fig Central Heating Temperature Sensor NTC FigSafety Thermostat Fig DHW Temperature Sensor NTC Fig Automatic Air Vent Fig Pump Head Only FigPump Complete Fig Pressure Relief Valve Fig Pressure Gauge FigsHall Effect Sensor Fig Plate Heat Exchanger Fig Diverter Valve Motor Unit & Assembly Fig 14.22 P.C.B. Fig Selector Switch Fig Expansion Vessel Fig Gas Valve Fig CO2 should be 8.4% ± Reduce CO2 Setting the Gas ValveSetting the Gas Valve CO2 check Flue Adaptor Test Point Plug Analyser Probe Electrical Illustrated Wiring Diagram 315316 311 404419 422 400 415 Short Parts ListShort Parts List 426 Error Codes Fault FindingInitial Fault Finding Checks Pump runs Error 133 flashingGo to section ‘A’ Turn the selector switch to Reset position for 5 seconds Close DHW tap Error 133 flashing Go to section ‘I’Turn Domestic Hot Water Open DHW tap fully Replace water PCB X3 connector terminals 3Switch terminal Fan jammed or faulty winding Replace PCB Replace gas valve Check wiring Viewing WindowReplace sensor or PCB E28 Gas at burner Replace sensor Replace safety thermostatReplace PCB Is there 230V at Pages for Notes Pages for Notes GAS Boiler System Commissioning Checklist Service Record Potterton