Main 12 HE A - Page 56

17.0 Fault Finding
56
© Baxi Heating UK Ltd 2014
OVERHEAT LOCKOUT
Replace Stat.
Replace Stat.
Wiring from PCB to
thermostats faulty.
YES
NO
YES
NO
NO
Disconnect
black stat on flow pipe.
When flow < 60° C is there
continuity across stat ?
Replace combustion
chamber door seal & trim
seal.
NO
YES
NO
YES
Reconnect stat.
Disconnect fan stat.
When fan temp < 60° C
is there continuity
across stat ?
Reconnect stat.
Disconnect the larger of
the 6-way PCB connectors.
Is there continuity
across M ?
Disconnect
thermistor
(red sensor on flow pipe).
Is resistance between
0.5kΩ & 20kΩ ?
Is
combustion chamber
door seal damaged or not in
place ?
Replace PCB.
YES
Replace thermistor.
M
6-way Connector
Lights
Flash Off On
ON