30
Concord CXS -
Installation & Servicing
F
AUL
T FINDING
F
AUL
T FINDING
FAULT FINDING
Is there a spark at the electrode?
Are the gas valve electrical plugs clean and secure?
43 BOILER DOES NOT LIGHT
Before carrying out any Fault Finding, ensure that all internal controls are calling for heat and that the overheat thermostat has not
operated. There should be 230V ± 10% available at the control box connection.
Is the spark gap approximately 4mm and are the
electrodes, leads and connections clean and secure?
NO
YES
YES
Is there 230V
±
10% at the gas valve plugs?
Is the gas valve inlet pressure sufficient?
Replace the gas valve
YES
YES
Are connections sound at
the plug-on terminal strip
at the control box?
YES
Is there 230V
±
10% at the spark generator
Replace
spark generator
Replace
PCB S4561B1047
YES
YES
44 BOILER LIGHTS BUT GOES TO LOCKOUT
NO
Measure the flame current - expect approximately 3.5
µ
A
Replace PCB S4561B1047
Check RH burner, inlet and burner pressure; check the
RH burner injector
YES
45 BOILER GOES OUT ON OVERHEAT THERMOSTAT
NO
YES
Is the flame detector and its lead and connections sound
and secure and correctly positioned on the RH burner?
YES
NO
Clean and secure
NO
Are the thermostat sensors in their correct pockets?
Refer to Installation Instructions for details
NO
Is there an unswitched Live supply to terminal L1 on
the plug-on terminal connection at the control box?
YES
YES
Is there sufficient open circuit water volume or load
available on boiler shutdown for the pump overrun?
YES
Is the pump (or shunt pump) wired to terminal L2
in the control box?
NO
Has the boiler thermostat knob been switched to OFF?
Replace PCB W4115A1020
Refer to Installation Instructions for details
YES
Advise USER
