Baxi Combi 133 HE Plus Installation & Servicing Instructions Manual page 56

FLOW THERMISTOR
Unplug
flow thermistor,
Is thermistor resistance between
0.5kΩ & 20kΩ ?
YES
Plug in
thermistor, unplug
8-way PCB connector.
Is resistance at V between
0.5kΩ & 20kΩ ?
YES
Replace PCB.
RETURN THERMISTOR
Unplug
return thermistor,
Is thermistor resistance between
0.5kΩ & 20kΩ ?
YES
Plug in
thermistor, unplug
8-way PCB connector.
Is resistance at U between
0.5kΩ & 20kΩ ?
YES
Replace PCB.
56
© Baxi Heating UK Limited 2005
LED
Lights
ON
NO
Replace flow thermistor.
NO
Wiring from PCB to flow
thermistor faulty.
LED
Lights
ON
NO
Replace return thermistor.
NO
Wiring from PCB to
return thermistor faulty.
15.0
Off
On
Flash
On
On
On
Flash
On
Fault Finding
V
Viewed from
Wire Entry end
U
Viewed from
Wire Entry end