Baxi Combi Instant 80 HE Installation & Servicing Instructions Manual page 48

Fault Finding Solutions
I
Ensure that mains input terminal L
is Live (230V) and N is Neutral
(0V)
YES
Check and correct if necessary
1. Flame sensing electrode and lead connections
2. Flame sensing electrode position
Flame current should be 1 µA approx.
J
Overheat thermostat operated or
faulty, i.e. continuity across
thermostat terminals
YES
K
Check terminal 1 of ON/OFF/RESET selector is in
connection with PCB - A4 connector terminal 2
Check electrical continuity across terminals 1 & a on reset
selector when turned to 'Reset' position
L
Check continuity of loop on
A10 connector
M
Is there 230V at:
Diverter valve operating head
1.
2.
PCB - A8 connector terminals 1
& 5 central heating function
1 & 3 DHW function
YES
Change motor supply cable
N
If checks in section I are completed successfully, blockage
of the condensate drain or trap may have occurred
O
If checks in section J are completed successfully, the flue
overheat thermostat may have operated. Press the reset
button on the flue overheat thermostat. If the boiler does
not relight or repeatedly cuts out. Check the operation of
the flue system or replace the flue overheat thermostat
48
YES
NO
Allow to cool. Continuity
NO
across thermostat terminals
more than 1.5 ohm
Replace main PCB
Replace main PCB
YES
NO
14.0
Replace main PCB
Replace flame sensing electrode
YES
NO
Replace ON/OFF/RESET selector
YES
Replace main PCB
Replace diverter valve operating head
Replace main PCB
Fault Finding
Replace overheat
thermostat