Pilot light went out but has reluctantly relit.

[lotstolearndiy]

We have a Glowworm Swiftflow 100 combi boiler.

Today we discovered that we had no hot water and then found that the boiler pilot light had gone out. We went through the lighting procedure. In order to light the pilot light you need to hold in the gas control knob, press the piezo to light the flame, hold the gas control knob in for another 15 seconds and then release. Unfortunately, the flame went out. So we had to wait for a while to have another go (there is a 4 minute safety mechanism). When we did try again (actually half an hour later), once the pilot light was lit, we held the gas control knob in for 1 minute. This time it remained lit. Hooray! However, I have some questions:
1. What could have caused our pilot light to go out in the first place?
2. What does it mean if it takes longer for the pilot light to heat up the thermocouple into a state where it will hold the gas valve open?
3. Are we likely to see this happen again soon and perhaps find that we can't keep the pilot light lit?

Thank you for any help.

 

[45yearsagasman]

The short answer is many things can cause pilot outage on these.A service will fix most problems,but be prepared to have some minor parts fitted.Is the fan running when the boiler is at rest with no demand?

 

[lotstolearndiy]

Yes, the fan appears to be running at half speed when the boiler is at rest.

 

[45yearsagasman]

Well thats saved a few quid then.A good service and maybe a thermocouple and a few pilot bits should solve your problem.

 

[Agile]

If the bvoiler is cold then 15 secs is rarely adequate to hold the button in.

I think the instructions says 30 secs or maybe longer.

Tony

 

[lotstolearndiy]

OK, so let's say that the thermocouple behaved normally when we came to relight it, what do you think could have caused the pilot light to go out? It was working this morning and then it had gone out an hour later. During that time we did not notice any power cuts.

Thanks

PS. It's not all that relevant but the instructions printed inside the door ask you to hold it in for 15 seconds. We probably did it for about 20s on the first attempt.

 

[Agile]

Most instructions say about 30 sec.

The fan could have stuck and stiffled the flame.

On other boilers a strong wind can blow them out but thats unlikely on your boiler.

You dont mention having had the boiler serviced! I suppose you have not bothered?

To do the job properly on your model the fan needs to be removed and cleaned. That can cause the terminals to break off.

Tony

 

[lotstolearndiy]

I do get the boiler serviced every once in a while but I don't think the guy takes the fan out.

 

[onlyfitidealboilers]

should be every year!!! gas appliances can kill

 

[Agile]

If you dont take the fan out and properly clean it then it gets clogged up very soon. The resulting unbalance can fail the fan bearings.

I wash the impeller under a running tap.

They are beautifully quiet when I have finished.

Unlike the Ideal Response with a 15 sec start up delay, those Swiftflows have the gas on within one second of turning on the tap and the pilot has preheated the water!

Tony

 

[lotstolearndiy]

Thank you everyone for your contributions.
I think I will have the boiler serviced and have the thermocouple changed while my engineer is here. It's a cheap precautionary repair.

Thanks again