Baxi Main Combi 24 HE Installation And Service Instructions Manual page 51

Fault Finding Solutions Sections G to L
G
1.
Check the burner setting pressure of the
(see Section 11.2 of Commissioning)
2.
Voltage at modulating coil of gas valve is:
Max. burner press.approx 9V DC (13V DC LPG)
Min. burner press.approx 1V DC
Current at modulating coil of gas valve is:
(Use an instrument with average function for this
measure)
30 ÷ 230 mA DC (45 ÷ 310 mA DC LPG)
H
Check and correct if necessary
1. Ignition electrode and lead
2. Electrode connection
3. Spark gap and position
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. Electrode position
Flame current should be 1 μ A approx.
J
Boiler 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 - M1 connector terminal 16
Check electrical continuity across terminals 1 & a of
ON/OFF/RESET selector when turned to 'Reset' position
L
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. If the
flue overheat thermostat has not been activated see section 'D'
© Baxi Heating UK Ltd 2011
gas valve
230V at Main PCB - M4
YES
connector across terminals
37 & 38. Check wiring
NO
Replace PCB
YES
Replace gas valve
NO
Replace PCB
NO
YES
YES
Replace PCB
NO
Replace flame sensing electrode
Allow to cool. Continuity across
thermostat terminals more than
1.5 ohm
NO
YES
16.0 Fault Finding
Replace PCB
Replace gas valve
electrical plug/igniter
assy
YES Replace boiler overheat
thermostat
Replace ON/OFF/RESET selector
Replace PCB
51