55
18.0 Fault Finding
© Baxi Heating UK Ltd 2012
E20 or E50 - Temperature sensors faulty.
Cold resistance approximately
10kí @ 25° C (DHW and CH sensors)
20kí @ 25° C (Flue sensor)
(resistance reduces with increase in temp.)
E28 - Incorrect PCB fitted
NO
E
Replace sensor or PCB (E28)
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
H
YES
1.
Ensure that the Hall Effect Sensor is in position.
Check the connection between the PCB - X400
connector terminals 3,6,7 and the electronic sensor
Check the voltage between red wire and blue
wire is more than 5V DC
NO
Replace PCB
Check and correct the connection of the
tube between the venturi and gas valve
Replace Hall
Effect Sensor
YES
1.
2.
Voltage at PCB - X2 connector is at
least 100V DC across terminals 2 & 5
(Note: from multimeter connect
‘common’ to 2 & ‘volts’ to 5).
Check wiring
7.5
±
1
4
±
0.5
1
0
±
1
Spark Ignition
Electrode
Sensing
Electrode