Boiler not firing

OllieN · 31 May 2006

My boiler has just stopped firing (yesterday).

It's a Gloworm Ultimate.

The heating and/or hot water comes on at the timer the 3 way valve and pump all leap into operation. Looking through the 'porthole' the pilot seems to have been lit but the main burner doesn't light / or try to light.

Any suggestions as to the likely problem?

Thanks in advance

Paul Barker · 31 May 2006

OK pump coming on eliminates external influences.

So check control signal has reached boiler, then check the various interuptors haven't kicked in, and finally check for instruction geting to the gas valve, ultimately check gas valve solenoid.

You can go so far in your checks then it requires a "competent person".

Soggy_weetabix · 31 May 2006

Pilot blockage is a common fault on these boilers. Especially if you have been away and left the boiler off for more than 3 days.

2 very small holes on the injector dont help. (an idea from Baxi SOLO's?)

And even a pin vice with the finest guitar wire wont clean an LPG injector on this boiler, as the holes are too small.

This is CORGI territory (sic) though.

A partial blockage will allow a 'pilot light', but not one that will allow the boiler to rectify.

When was it last serviced?

David

geoff@cetltd · 1 Jun 2006

Nobody seems to have mentioned that this could be a flame sensing problem

Does it continue to spark once the pilot is alight?

... or it could be the GV relay on the pcb

... or the main valve solenoid

meldrew's_mate · 1 Jun 2006

Does the pilot go out when the boiler demand is removed (assuming fan flue & auto ignition model). Have known the gas valve to fail to shut off the pilot supply, thus the flame rectification part of the PCB will not allow re-ignition. You can test for this by turning off the boiler and the gas supply to the boiler, re-establishing it, then turning the boiler back on. If this is the right diagnosis the boiler will light once only.

How about expanding on the model of boiler as there are several Ultimate derivatives.

OllieN · 1 Jun 2006

Apologies I don't know the model derivative and am now at work so can't check.

The pilot extinguishes and relights on demand (Certainly when I turned the boiler on and off last night - I didn't shut off the gas supply however). It doesn't appear to continue sparking once the pilot is lit just the main burner won't start.

I presume it has been serviced within the last year as the previous home owner had a service plan with British Gas.

Soggy_weetabix · 1 Jun 2006

OllieN said:
Apologies I don't know the model derivative and am now at work so can't check.

The pilot extinguishes and relights on demand (Certainly when I turned the boiler on and off last night - I didn't shut off the gas supply however). It doesn't appear to continue sparking once the pilot is lit just the main burner won't start.

I presume it has been serviced within the last year as the previous home owner had a service plan with British Gas.

Thats proof the boiler has not been serviced!

If the boiler has rectified (not continuing to spark) you may have solenoid failure if the main burner will not ignite, or a failure in the rectification device.

David

geoff@cetltd · 1 Jun 2006

If you have and understand how to use a DVM, you could test the gas valve solenoid / pcb

1/ check the resistance of the solenoid, it should be several hundred - several thousand ohms, not open circuit

2/ Check whether you have 240 volts across the solenoid when you expect the main valve to come on

OllieN · 5 Jun 2006

OK, so I couldn't test the resistance, but the main valve solenoid does have 240V across it when expected to fire.

The make of boileer is a Gloworm Ultimate xxFF (xx would be 30/40/50/60) not sure which according to the manual.

Went through the troubleshooting flowchart in the manual also and sounds like the multi function control (main solenoid/valve/pilot assembly?) needs replacing. Would you folks agree with that? Is it the whole control that has to be replaced or is there just a part that can be done? How much would I be looking at to have this done?

Thanks for all your help

geoff@cetltd · 5 Jun 2006

my guess would be that the main GV solenoid has gone open circuit

really you need to check the resistance somehow

ollski · 5 Jun 2006

Is it the one with the 2 single solenoids in the blue cover on the back of the gas valve?

OllieN · 6 Jun 2006

What would be the fix for an open circuit solenoid? Replacement? Can I replace just the solenoid or is it the whole control.

Yes it is the one with the two solenoids under a blue cover, in my installation on the underside of the gas valve. If I'm right one does the pilot light and one the main burner?

ollski · 6 Jun 2006

OllieN said:
What would be the fix for an open circuit solenoid? Replacement? Can I replace just the solenoid or is it the whole control.

Yes it is the one with the two solenoids under a blue cover, in my installation on the underside of the gas valve. If I'm right one does the pilot light and one the main burner?

yes, you can swap the solenoids over to prove the fault as the pilot won't light.

OllieN · 6 Jun 2006

Is solenoid swapping an easy task? How do I go about it? Just thought I'd ask now before getting home tonight and seeing that I had no clue on how to do it!!

Presumably if solenoid is the problem take the duff one to my nearest supplier and get a replacement? Where would be likely to sell replacement solenoids?

ollski · 6 Jun 2006

Just make sure all the power supplies are isolated. 2 long screws come out to remove the blue cover then each solenoid is held on by a locking nut. Undo them, swap them over and replug the wires and hey presto you should have absolutely nothing. Then you can go to hrpc and see if they have got a replacement.

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Boiler not firing

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