Pilot light won't relight, cleaner added to header tank ...

Hi there I hope somebody is kind enough to help me...?

Basically yesterday I added (or my husband did) a central heating cleaner into the header tank, and drained some water from the drain point near our patio door to get it into the pipes.

Late last night our boiler (old, about 15-20 years old I would guess) pilot light went out. It was very windy outside and we had our patio doors open, but I don't know if that would make it blow out? Anyway, my husband has tried to ignite it but no joy-a few times it lit but then quickly went out again.

Is there anyway or anything we are doing wrong, to light it properley again? Has the cleaner made this happen??

The cleaner is irrelevant!

Yesterday was very windy and that caused the pilot light to go out.

It seems that you have not had your boiler serviced anually which is very important for old boiler which are not room sealed as they can become dangerous if not regularly maintained.

You need to call a competent CORGI to come and service the boiler, clean the pilot assembly and replace the thermocouple. Tell him the make and model of boiler so he brings the right parts.

An important part of his visit will be to test the boiler to ensure that its operating safely.

Tony

Thank you for your adice and I will have to call a local corgi registered plumber in to service the boiler.

It just seemed such a coincidence that about 1.5 hours after I addded the cleaner, it went out! it was very windy though and there was a small storm that night!

One point though-if the pilot light was blown out; how comes the thermocouple has worn out at the same time? Is this common-or just over time it is worn and when the pilot is blown out, it has trouble re-energising the soleoind??? Just curious really.

How much is a service likely to cost, as a rough guide please?

Thanks for your help

The thermocouple deteriotes gradually over time and usually manifests the problem when someone trys to relight it.

I hope he was holding the gas valve knob for at least a minute before releasing it after the flame lit?

The boiler is probably pretty inefficient and a replacement condensing boiler would probably save about 30-40% on your gas bill !

Tony

yes he held it in for quite a while, but when he released it slowly it went out. he said it sparked though and lit but would not hold.

What boiler is it?

A few have the pilot light in series with the thermocouple, so if the boiler overheats it trips the thermocouple out as the safey device.

Outside chance that he may have caused an airlock that made the boiler overheat

had the same thing last week

top thinking gas4you

Have a corgi plumber coming round tomorrow!

but am confused now what to ask him/what has happened with your kind replies:

basically, what happened was:

when the system is turned on, after a while 2 pipes up to the header tank rattle and bang and water comes out of the top pipe. then a gushing sound occurs for about 20 seconds and then nothing. but this process continues about every 6-7 minutes.

So my husband thought sludge may have blocked some cold pipe and added cleaner into the header tank, then he drained a few gallons of water to get the cleaner into the pipework.

then that night the pilot went out and won't restart. the boiler is very old, and is a gloworm. he was re-ignited it in the past years ago and it was ok, but not now. so what has happened - has what he added caused it to not restart?

as mentioned the boiler has not been serviced and maybe needs a clean and a new thermocouple. i believe now that afte reading other posts, that the boiler thermostat may be faulty, thus the original cause and not sludge build up.

i will explain this tomorrow to the plumber, but hope the pilot failing to relight wasnt our fault and was just a co-incidence? any ideas? if the boiler was already overheating from the boiler stat would an airlock then also cause it to overheat or was the problem already there?

Thinking about it now: maybe the original overhteaing (from a boiler thermostat failure) is preventing the boiler pilot re-lighting? It was very windy the night that it pilot went out, is this common with older natural wall flues? So the thermocouple is no holding due to the overheat situation?

gas4you said:

What boiler is it?

A few have the pilot light in series with the thermocouple, so if the boiler overheats it trips the thermocouple out as the safey device.

Outside chance that he may have caused an airlock that made the boiler overheat

Click to expand...

sorry for the long post: but the boiler must have been overheating already - as water was coming from the vent pipe before the cleaner was added. so why wouldn't the boiler have cut out before and the pilot gone out earlier, a mean weeks ago? it is an old boiler though.

also the pilot won't relight days after, when the boiler is cool. it won't hold at all - if it lit and then when heated went out then i'd think an airlock may be the problem though?

the flue is through a wall, but the boiler is not fan operated btw.

You are now giving us much more information and particularly that the boiler has been sadly neglected.

If you added chemicals then you only needed to take about 1-2 gallons out of the system and not more. Hopefully the level went down when water was taken out.

After these multiple overheats you may have damaged the overheat thermostat. Or alternatively it may just be a failed thermocouple as you boiler have not seen a proper service for ages.

Tony

Hi Agile:

yes the water level went down in the f & e cistern when my husband drained down, i held the ballvalve up. then we added the cleaner and the let the ballvalve go and it went into the pipework.

yes i am afraid the boiler has been neglected. i don't know if it has an overheat stat as it is an old boiler - i think it may just have a normal boiler thermostat. but wouldn't my room thermostat and cylinder tank stat cut off the supply of heated water before the boiler thermostat setting anyway? thus i don't see what the boiler thermostat failure could have happened? if course i am no an expert!

and if the boiler thermostat had failed, wouldn't the thermocuple and pilot light have gone out weeks ago when the problem started and the overhteaing started (if they are in series )??
it is weird that it went out the night after the cleaner was added!

Generally there should be no connection however, if you took weater out faster that you replaced it then you could have brought air into the system and that could have created a lack of flow and so the boiler could have overheated.

Thats only a possibility though!

I expect the thermocouple has failed but any competent boiler engineer will be able to find the cause and repair it.

The key word is competent but its a very low tech boiler!

Tony

low tech as in rubbish do you mean?!!

i understand what you are saying about air, but surely the boiler was overheating anyway before..... with the boiler stat failure?? so why didn't the pilot go out weeks ago if in series with the thermcouple?

doesnt a room stat cut out before the boiler stat anyway-meaning the boiler stat temp would not be reached?


also though, the pilot should have lit and held, as it isn't overheated now!!! it just wont hold at all!!

You still fail to tell us the make/model of the boiler

This is an old floor mounted GlowWorm CF boiler and its not significant exactly which one it is.

A few CF boilers had an overheat stat in series with the thermocouple but most did not!

The boiler has its own stat ( knob ) to set the flow temperature from the boiler.

The room stat turns off the boiler when the room is warm.

You keep saying the boiler or system is overheating. Its not clear if this was before you added the chemical or after. That might be air in the system or a blockage or the boiler stat sticking on or the pump failing. Several things to be checked!

Tony