Baxi System 100 HE Plus Installation & Servicing Instructions Manual page 48

FAN LOCKOUT
Unplug
3-way PCB connector
& unplug fan. Is there
continuity from N to O &
from P to Q ?
YES
Unplug
the smaller of the
6-way PCB connector. Is there
continuity from R to S & from T
to U & from
V to W ?
YES
Replace fan.
THERMISTOR
Unplug
thermistor,
Is thermistor resistance between
0.5kΩ & 20kΩ ?
YES
Plug in
thermistor, leave
8-way connector unplugged.
Is resistance at D between
0.5kΩ & 20kΩ ?
YES
Replace PCB.
48
Flash
Lights
Flash
On
ON
NO
Rectify wiring.
NO
Rectify wiring.
Lights
ON
NO
Replace thermistor.
NO
Wiring from PCB to
thermistor faulty.
15.0
NOTE: The fan is supplied with 325 Vdc.
Fan Fault Finding should only be carried out after the
boiler has been electrically isolated.
Fan
Connection
N
P
Fan
Connection
R
T
V
On
Flash
On
Fault Finding
PCB
Connection
PCB
Connection
Viewed from
Wire Entry end
D
Viewed from
Wire Entry end
O
Q
S
U
W