Potterton Promax FSB 30 HE Installation & Service Instructions Manual page 54

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.
54
© Baxi Heating UK Limited 2010
Lights
On Off onn *
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