Potterton Promax Store 24 Installation And Service Manual page 52

H
1. Check the gas supply pressure:
For Natural Gas greater than
2.
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
I
1.
Overheat thermostat operated
or faulty, i.e. continuity across
thermostat terminals
J
Is there 230V at:
1.
Motor 3-way valve
2. PCB - X3 connector terminals
5 & 6 central heating mode
5 & 7 domestic hot water mode
Change pump supply cable
K
1.
Fan connections correct at fan.
PCB - X401 connector terminals 5,6,7 & 8
L
1. Temperature sensors faulty.
Cold resistance approximately
10k @ 25° C (CH sensor)
20k @ 25° C (Flue sensor)
(resistance reduces with increase in temp.)
2.
If pump is running the heat exchanger could
be obstructed
52
10 - 11 mbar
NO
YES
Replace PCB
YES
YES
YES
Replace PCB
NO
Replace flame sensing electrode
Allow to cool. Continuity
across thermostat terminals
more than 1.5 ohm
Replace diverter valve actuator
NO
Replace PCB
YES
Replace fan
NO
Replace sensor
YES
Replace heat exchanger
YES
Replace safety thermostat
© Baxi Heating UK Ltd 2015