Glow worm combi boiler

[GazKaz]

Hi all

I have a Glow Worm combi boiler that is about 6 years old feeding 8 rads in total. Overall it has performed great but recently I have noticed something about the boiler.

When it is on, heating the rads, every now and again you can hear the igniter in the boiler clicking furiously, even tho the burners are already on! It does not happen a great deal, but I do notice it every once in a while.

Any help would be appreciated.

thanks

gazkaz

 

[andsam]

Are 100% sure it is the boiler trying to ignite if so i would expect the burner to knock of. If it is the CI range of combis they have a stepper motor in the gas valve that can give a kind of ticking noise when modulating.

 

[GazKaz]

Hi andsam

I'm pretty sure it is trying to ignite. It gives the same clicking noise when it does ignite properly.

My Glow Worm combi is from the "Compact" range.

One other note, in the 5 or so years I've had the system, the boiler has never been serviced.

Many thanks

GazKaz

 

[andsam]

On some earlier compacts they had problems with the burner not cross lighting correctly but this caused the boiler to go to lock out. Have you had lock out probs.

 

[GazKaz]

I take it by "lock out" you mean stop working?

It performs great apart from this little problem. It certainly hasen't died on me (touch wood)

 

[andsam]

If the flame picture is lifting it could be a problem with the flue. This sometimes happens if the inner flue leaks products into the outer flue.

 

[carpet]

GazKez,

I have the same problem but my boiler seems not to work at all, no hot water and no Central Heating.

I get a constant clicking noise, it is the ignition to the pilot light, the pilot light is lit though !!!!

Any one any ideas, it is A Glowworm boiler, about 8 years old.

Went wrong probably Monday 14th

Any help will be appreciated....

 

[Ticker]

Hi
Could this be a faulty component in the ignition detection circuit on the sequence pcb. Assuming there isn't an intermittent sensor switch which is momentarily locking out gas supply/re-enabling the ignition sequence. (although not sure if this is would close down gas supply and restart whole ignition sequence)
However Glow Worm technical help desk explained the following to me:-
On the gw fuelsaver 55F, the spark from the single electrode discharges to ground, with gas supply enabled to the pilot jet, the gas ignites, the boiler jets light, the flame ionises the air gap in the spark discharge path, this changes its resistance, this changes spark eht current flow/voltage and is detected by a simple but clever circuit, suspending spark sequence's eht supply.

Regards
Ticker

 

[Agile]

Its nearly correct!

Actually the circuit is not sensing just a resistance as damp or carbon could give that.

The moving gas flow in the flame causes a lower resistance in one direction. This is detected by applying an AC voltage to the electrode WHILE it is sparking and if there is a flame this gives a DC offset voltage which is detected and then enables the main gas valve and stops the sparking.

Tony

 

[Ticker]

Hi Tony
I'm grateful for your explanation, I have to admit I was incorrectly paraphrasing what I had heard. I was only told that there was a change, caused by the ionisation. I didn't question the scale of the change, it's even cleverer than I thought; I wonder how this phenomenon was discovered?

Regards
Ticker