Potthof & Co Potterton Gold HE Range Condensing Combination Boiler 33kw - Manual (Page 59)

59
© Baxi Heating UK Ltd 2012
18.0 Fault Finding
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
Replace PCB
Replace PCB
YES
YES
Replace flame sensing electrode
NO
Check that the supply pressure at
the test point on the gas valve is a
MINIMUM of 17mbar
I
K
Replace safety thermostat
YES NO
Overheat thermostat operated or
faulty, i.e. continuity across
thermostat terminals
Allow to cool. Continuity
across thermostat terminals
more than 1.5 ohm
J
L
M
Is there 230V at:
Motor 3-way valve Replace motor 3-way valve 1.
YES
PCB - X3 connector terminals
5 & 6 central heating mode
5 & 7 domestic hot water mode Replace PCB 2.
NO
Change pump supply cable
YES
Fan connections correct at fan.
PCB - X401 connector terminals 5,6,7 & 8
1.
YES
Replace fan
Temperature sensors faulty.
Cold resistance approximately
10kí @ 25° C (CH sensor)
20kí @ 25° C (Flue sensor)
(resistance reduces with increase in temp.)
NO
Replace sensor
YES If pump is running the heat exchanger could be
obstructed
Replace heat exchanger
1.
2.
1.
2.
1.