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

[pamelaswift]

sorry-the boiler was pumping water over into the header tank after it was on for about 20-30 mins, then this procedure repeats itself every 5-7 minutes. this was happening from about 6-8 weeks ago. i added the cleaner after as i thought it may be sludge causing the vent pipe to discharge (blockage at the tee join between the cold feed and vent pipe as said on the FA section). (or my husband did should i say).

the pilot went out the evening after we added the cleaner, it may be just bad luck but i am not sure? it was windy though that night.

the boiler is in a cupboard, wallhung i would say. old looking and hasnt been serviced for years and years.

if the pilot was cutting out due to overheating, then why did it not go out weeks ago when this boiler thermostat problem started? it is weird!

 

[gas4you]

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

Don't know about golden balls, but you must be crystal balls

Where has the OP told us it is a Glow Worm FS boiler

It is significant which one it is, as if it is a Hideawy CF, they have the flue sensor in series with the thermocouple and this is not self re-setting, it needs the reddish brown button pushed back in before the pilot will stay alight

 

[pamelaswift]

so if the flue sensor is in line with the thermocouple, why has this caused the pilot to not light? what is the cause? is it a big thing? i am sorry i dont know the model of the boiler.

 

[poolebybirth]

You adding cleaner to your header tank had nothing to do with it cutting out and not re-lighting-if your boiler has been overhteaing for a while now, then it would have cut out then.

More than likely it was just a coincidence and the thermocouple has pited, as they do over years, and your boiler as you say is very very old.

It needs a good service, a new thermocouple by the sound of it, and a new boiler thermostat.

Your boiler probably does not have an overheat boiler thermostat that trips when the normal boiler thermostat fails - and thus the ejection of hot water/steam (100 degrees) from the vent pipe, into the header tank.

The boiler stat CAN fail (stick) even if the room thermostat and cylinder thermostat are satisfied well before the boiler thermostat's setting.

 

[Soggy_weetabix]

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

I was thinking, was the system partially drained to allow the inhibitor to access the system?

If it was, I would suggest Dave has a good point

 

[pamelaswift]

yes the system was drained to allow the cleaner into the system.

BUT why would the pilot go out if an airlock had caused it to overheat. A) it is an old boiler and may not be so sophisticated and B) the boiler must have been overheating for weeks as the boiler thermostat seems to have failed, and the vent pipe was steaming!


if it was to be an airlock, would draining more water from the system cure it, and then the pilot re-light again?

 

[gas4you]

so if the flue sensor is in line with the thermocouple, why has this caused the pilot to not light? what is the cause? is it a big thing? i am sorry i dont know the model of the boiler.

If the flue sensor has tripped the pilot wll not light as this is a safety feature to stop the boiler if th flue has blocked or if there is a significant downdraft.

If it is a Hideaway the reddish brown reset will be just above the gas valve. push it in and see what happens.

 

[pamelaswift]

Hi

I don't think the flue is blocked - and the flue is through the wall, not an open type through the chimney. i don't have that button though anyway. Thanks for your help though.

Can someone please explain this to me though: if my boiler had an overheat cut out , where thew thermocouple and pilot light are in series, (as with an airlock causing the boiler to overheat as mentioned) - if the boiler stat has failed and stuck and the water was reaching 100 and being pumped out of the vent like mine - wouldnt this over heating have caused the boiler to lock out (and pilot to go out) weeks ago?

 

[gas4you]

I wasn't implying the flue was blocked, just trying to answer your question.

Personally I don't feel I can help further without accurate info on the boiler

 

[steved101]

if you drain some more water from the drain point, then you may shift the airlock and the boiler's pilot light may re-light again. although this may not be the reason... you may need a new thermocouple, sounds like a new boiler stat is required and also a good clean/service of your boiler.

 

[pamelaswift]

got the plumber coming tomorrow. what are the odds though on me and my husband draining some water from the system, to add cleaner to the header tank, and air getting in (as i held the ballvalve up for a few mins when he drained a bit to check we didnt have a blocked cold feed and the tank would empty to the feed outlet level, and the boiler getting airlocked later on and the pilot then going out later on on overheat?! and its an older boiler.

 

[Agile]

She said some while ago that she had an old GlowWorm and that it had a natural wall flue.

I wrongly interpreted that to mean that it was a floor mounted boiler with a natural draught flue up a chimney.

Later, mixed in with her ongoing fixation with the association between adding chemicals and thepilot going out.

It now seems to be a wall mounted boiler with, probably, a balanced flue and in that case the chance of having an o/h stat in series with the T/C becomes higher.

her description of how much water was let out is rather variable and does not specifically tell us if she drained it BELOW the outlet on the F&E tank.

Anyway hopefully she might have managed to get an RGI with a modicum of understanding of boilers. We will have to wait for her to probably tell us that its too old to mend and for a couple of thousand he will fit a new boiler!

Tony

 

[pamelaswift]

im still here!

yes my boiler is wall hung. but a lot of older boilers had no overheat stats apparantly, thus the overheating via the vent pipe.

i dont want a new boiler - can't afford it!

we drained the water level to the cold outlet which was about 1.5 inches up from the base of the cistern.

 

[andytheplumber]

Sounds like you need a new house

 

[Agile]

im still here!

we drained the water level to the cold outlet which was about 1.5 inches up from the base of the cistern.

If you did not allow a lot of air to be sucked into the pipes then much of the advice above is irrelevant.

We dont know your exact model but quite a lot of wall boilers do have a seperate o/h stat which takes out the pilot to protect the boiler.

Tell us what the engineer says and does to fix it. Some of them are waiting with baited breath!

Tony



PS did anyone like my mistake?