54
18.0 Fault Finding
© Baxi Heating UK Ltd 2014
Temperature sensors faulty.
Cold resistance approximately
10k
Ω
@ 25° C (DHW and CH sensors)
20k
Ω
@ 25° C (Flue sensor)
(resistance reduces with increase in temp.)
NO
E
Replace sensor
Gas at burner
Ensure gas is on and purged
Replace PCB
Replace gas valve
PCB - X3 connector is 230V AC across
terminals 1 & 2
YES
NO
NO
F
Replace PCB
G
Check and correct if necessary
1. Ignition electrode and lead
2. Electrode connection
3. Spark gap and position
YES
NO
Replace igniter
YES
Check and correct the connection of the
tube between the venturi and gas valve
1.
2.
Voltage at PCB - X2 connector is at
least 100V DC across terminals 2 & 5
(Note: from multimeter connect
‘common’ to 2 & ‘volt’ to 5)
Check wiring
7.5
±
1
4
±
0.5
10 ±1
Spark Ignition
Electrode
Sensing
Electrode
Electrode Position
Viewing Window
Burner