Potterton Promax 12 SL Installation And Service Instructions Manual page 53

OVERHEAT LOCKOUT
Disconnect
black stat on flow pipe.
When flow < 60° C is there
continuity across stat ?
YES
Reconnect stat.
Disconnect fan stat.
When fan temp < 60° C
is there continuity
across stat ?
YES
Reconnect stat.
Disconnect the larger of
the 6-way PCB connectors.
Is there continuity
across M ?
YES
Disconnect
thermistor
(red sensor on flow pipe).
Is resistance between
0.5kΩ & 20kΩ ?
YES
Is
combustion chamber
door seal damaged or not in
place ?
NO
Replace PCB.
© Baxi Heating UK Ltd 2007
Lights
Flash Off On
ON
NO
Replace Stat.
NO
Replace Stat.
NO
Wiring from PCB to
thermostats faulty.
NO
Replace thermistor.
YES
Replace combustion
chamber door seal & trim
seal.
17.0 Fault Finding
M
6-way Connector
53