Flame On Before Gas Valve On; Low Water Pressure; Flame Loss - Keston Combi C30 Installation And Servicing Instructions

4.4 FLAME ON BEFORE GAS VALVE ON

Restart the boiler, does Boiler Work OK?
NO
Separate the flame detection electrode in-line connector. Is there
continuity between the terminals pins connected to the electrode?
RESTART PROCEDURE - To restart boiler, turn mode knob to restart position and immediately turn knob back to required setting.

4.5 LOW WATER PRESSURE

Are the Boiler and CH System filled with water and all isolation and
radiator valves open (check pressure gauge is between 1 to 1.5 bar)?
Are connections on water pressure sensor secure?

4.6 FLAME LOSS

Does the boiler ignite for a short
time and then extinguish?
YES
Check the detection electrode and
associated harness for: continuity,
visual condition and position
(Refer to Section 3.14). Check if
condensate pipe is blocked. Check
if flue is blocked.
Replace as necessary
62 62
SECTION 4 - FAULT FINDING
YES
YES
NO
Is the Gas Pressure available at
the Boiler Inlet (>18 mbar)?
Is 24Vdc supply available at the
Gas Valve while the flame is on?
Check spark generator and associated
harness for: continuity and visual
condition. (Refer to Section 3.15) Are
these functioning correctly?
Check ignition electrode and associated
harness for: continuity, visual condition
and position. (Refer to Section 3.13)
Are these functioning correctly?
Check siphon and condensate
drain pipe work for blockage and
rectify if necessary. Boiler now
working OK?
Check routing and integrity of internal boiler wiring is OK. Check
condition of Flame Sense Electrode and replace if deteriorated.
YES
Replace Flame Detection Electrode
NO
Check routing and integrity of internal boiler wiring
NO Fill and vent the system and open all
isolation valves
NO
Re-fit connections
Replace water pressure sensor
YES
YES
YES
YES
YES
NO
Check gas supply and
rectify fault
Check wiring from gas
NO
valve to PCB for continuity.
If the wiring is OK then
replace the PCB
NO
Replace Spark Generator
and Harness as necessary.
Replace Ignition
NO
Electrode and
associated harness as
necessary
NO
Replace Gas Valve
Installation and Servicing