Quick Start Manual

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