Pilot light always on?

[mane]

Hi,

I have been having lots of grief with my Glowworm back boiler in the last 2 years. It has been serviced and repaired several times in the last 2 months. It actually got a new PCB, new combustion products safety device and also a new gas control valve. This also happened a year ago where all these parts have been replaced.

Despite this, and since yesterday, the pilot light remains lit permanently. Even turning the mains off it still remains on.

My concern is obvsiouly safety because I am wondering whether the gas will cut off if the pilot goes off. Any clues as to what is going on? Can gas control valves be so unreliable? This is the third one and it is only 2 months old (I hope)!.

Any comments?

 

[ChrisR]

Most back boilers have permanent pilots. What model is yours exactly?

Assuming it's designed to have a permanent pilot, the pilot holds a gas valve open via a thermocouple, which detects the flame's heat. If the gas goes off, the thermocouple cools and shuts the gas off. You have to turn it on manually, when relightng the pilot.

If yours doesn't have a PP, then it's unusual to fail so soon. Some gas supplies have a lot of sulphide flakes in them, which aren't entirely held back by the gas valve's inlet filter.

 

[gas4you]

Hi,

I have been having lots of grief with my Glowworm back boiler in the last 2 years. It has been serviced and repaired several times in the last 2 months. It actually got a new PCB, new combustion products safety device and also a new gas control valve. This also happened a year ago where all these parts have been replaced.

Despite this, and since yesterday, the pilot light remains lit permanently. Even turning the mains off it still remains off.

My concern is obvsiouly safety because I am wondering whether the gas will cut off if the pilot goes off. Any clues as to what is going on? Can gas control valves be so unreliable? This is the third one and it is only 2 months old (I hope)!.

Any comments?

What Glow Worm model is it? Most use PCB to ignite pilot then this remains on until it goes out for some reason. If yours is a model with a thermocouple turn the gas valve knob off (the grey one usually, or the one you have to hold in whilst you light the pilot) you should here a click within 60 seconds which is the gas shutting off.

If it is an electronic flame rectification model and the pilot goes out you should here a constant 'ticking' as the PCB tries to relight the pilot, the same as ignition on cooker hob burners. I hope you have not been charged for each of these gas valves as they all come with 12 months warranty!

 

[mane]

Hi,

Sorry I forgot to include the boiler model. It is an Inset BBU50 http://www.glow-worm.co.uk/manuals/pdf/Back Boiler Units/Inset50BBU_UIS.pdf

The gas valve is actually this one http://www.sitgroup.it/content/view/120/lang,en/

I have a maintenaince contract so other then the monthly payments I haven´t paid anything else. The main issue here is the inconvenience of having to stay at home for the repair. It is getting increasingly difficult to ask for time off due to the boiler. I had an engineer in 6 or 7 times since January.

Three parts replaced, 2 visits each - one to make the decision to replace the part and another to actually install the part. The additional visit was prior to the boiler breakdown for the normal anual service.

I am wondering whether the valve is stuck in the opened position. I have the old valve and I will take it apart to figure out how it works. I don't know if the solenoid push/pull the rods or rotates them.

I could be a solenoid failure but I assume that the valve as a fail-safe feature which shuts it in case of solenoid failure.

In any case thank you for the comments so far.

 

[mane]

Most back boilers have permanent pilots. What model is yours exactly?

If yours doesn't have a PP, then it's unusual to fail so soon. Some gas supplies have a lot of sulphide flakes in them, which aren't entirely held back by the gas valve's inlet filter.

Hi,

Is it possible that all these recent gas valve failures are related with my gas supply? If that is the case is there any solution?

Thanks

 

[Agile]

Its difficult for us to reach any conclusion about your problem.

This is because there are two problems, we cannot assume that the parts were necessarily replaced because they were faulty.

Its common for parts to be replaced because the engineer cannot diagnose exactly whats faulty. Also some service contractors "make up" faults to give themselves jobs to do.

Did the people who have attended not tell you what was wrong or did they seem not to fully understand the problem.

I dont see how your gas supply can be relevant. Any dirt will be trapped by the gas valve inlet filter where it would be visible if the valve is removed. That does not seem to be the problem.

Any part can fail once in a while. The most common fault on gas valves is the solenoid failing but that is not very frequent, perhaps one in a thousand during the warranty period.

Boilers are very reliable. I had to change a gas valve on a 30 y.o. boiler recently because the internal bits had worn out but thats not so surprising when the life of a boiler is only expected to be 10-20 years.

Tony

 

[gasgeezer]

I think you have a MK111 boiler if so the pilot lights when calling for heat and will stay on untill switched live is off. Have you turned the power off or just the boiler stat could be ext. valve sticking sending power to boiler,also there is a jumper on the p.c.b which s/be removed not sure if that would cause this problem though.

 

[mane]

Hi Tony,

Yes, you may be right! Perhaps I am wrong but it appeared to me that the engineer seemed not to fully understand the problem.

The problem with the boiler was that it would not fire most of the times. The symptoms were as follows:

1) Demand for heat
2) Clicking noise and pilot light comes on
3) After some time, a second click and green light would come on
4) After this no gas flow could be heard and the red light would come on.
5) Upon pressing the reset button the boiler would fire most of the times.

When the engineer came for the first time we could not replicate the problem because the boiler would operate normally. Using the troubleshooting diagram he decided to replace the PCB and ordered the part.

In the second visit he then replaced the PCB. When he arrived the boiler has the red light on because I left it in the fail condition since the last time it failed (that morning). When he left all appeared working. As soon as he left the boiler didn't fire again as explained above.

Engineer called in again and this time he decided to replace the combustion products safety device which includes a new thermocouple.

Despite this the problem remained. The final thing to do was to replace the gas valve. This seemed to solve the problem and the boiler has been working fine in the last 3-4 weeks.

This episode is identical to one exactly one year ago including the multiple visits.

Now the problem seems to be different has it looks like the pilot light gas valve seems to be doing nothing. The boiler does actually fire very well as it does not have to wait for the thermocouple to heat up. So as soon as there is demand for heat the boiler turns on instantly.

What I would really like is to someone to find out what is the underlying problem so that it does not come back again. I also find it difficult that the boiler worked well for so many years and suddenly it fails twice in the space of 12 months. And now again

I will call in the engineer again, they will replace the gas valve (involving 2 visits) and this problem will come back for sure! This will only stop when the cause of the failure is addressed.

Sorry for the lenght of the message

Mane

 

[gas4you]

Hi,

I have been having lots of grief with my Glowworm back boiler in the last 2 years. It has been serviced and repaired several times in the last 2 months. It actually got a new PCB, new combustion products safety device and also a new gas control valve. This also happened a year ago where all these parts have been replaced.

Despite this, and since yesterday, the pilot light remains lit permanently. Even turning the mains off it still remains off.

My concern is obvsiouly safety because I am wondering whether the gas will cut off if the pilot goes off. Any clues as to what is going on? Can gas control valves be so unreliable? This is the third one and it is only 2 months old (I hope)!.

Any comments?

Afterreading the manuals at the links you supplied I would go for a faulty gas valve. This assumes that you have checked your electrical supply and can confirm that it is definitley off when you switch off at you heating isolating point!

 

[mane]

Afterreading the manuals at the links you supplied I would go for a faulty gas valve. This assumes that you have checked your electrical supply and can confirm that it is definitley off when you switch off at you heating isolating point!

Thanks for taking the trouble to do this.

Yes I have turned of the power at the isolating point.

I wanted to do a test but I am not sure if I should do it for safety reasons. However I really wanted to test whether there is any fail-safe mechanism still in place. What I wanted to do is to turn the gas off at the gas metter. This would surelly extinguish the pilot flame. The problem is if the gas valve remains open after I turn the gas back on. Would there be any problem in turning the boiler on with the gas off and than only turn the gas back on when the pilot is clicking?

 

[gas4you]

Afterreading the manuals at the links you supplied I would go for a faulty gas valve. This assumes that you have checked your electrical supply and can confirm that it is definitley off when you switch off at you heating isolating point!

Thanks for taking the trouble to do this.

Yes I have turned of the power at the isolating point.

I wanted to do a test but I am not sure if I should do it for safety reasons. However I really wanted to test whether there is any fail-safe mechanism still in place. What I wanted to do is to turn the gas off at the gas metter. This would surelly extinguish the pilot flame. The problem is if the gas valve remains open after I turn the gas back on. Would there be any problem in turning the boiler on with the gas off and than only turn the gas back on when the pilot is clicking?

Firstly I can not stress enough that if you are not confident in any of your abilities leave well alone and recall your service company. We are not instucting you on how to solve problems but giving general advice. Do not open or touch any electrical connections yourself.

If the main boiler is alight and you turn off the power does it go out? If so sounds like power is going off.
If ignition is clicking then pilot should ignite ok after a while. This is the main safety purpose of auto flame rectification and ignition, to protect you if the gas supply is disrupted then restored without your knowledge. This could take longer if you have turned gas off at meter as the pilot will have used the gas in the pipe work.

 

[ChrisR]

Yes it's supposed to spring shut. Turning the mains off as you have, eliminates the pcb.
Yes it's a pain taking time off work - some of us make early evening visits!

Only thing I can think you could do is get a sulphidation filter put in the gas line, which will catch anything above 50 microns. Eventually of course that will block up, but it should only be one visit to clear it!

Check that the gas valve isn't getting too hot for some reason, like a heat shield missing.

 

[mane]

If the main boiler is alight and you turn off the power does it go out? If so sounds like power is going off.

Yes, when power is off the boiller turns off with the exception of the pilot flame which remains on.

This is the main safety purpose of auto flame rectification and ignition, to protect you if the gas supply is disrupted then restored without your knowledge.

This is what worries me. If the flame goes out because the gas supply is cut without my knowledge for example, then when the gas supply is restored I will know about it too late ....

 

[gas4you]

This is what worries me. If the flame goes out because the gas supply is cut without my knowledge for example, then when the gas supply is restored I will know about it too late ....[/quote]

Yes I understand but this is the point of the flame rectification and ignition sparking when no pilot light is detected. The pilot will re-light automatically if the ignition and pcb etc are working correctly

 

[mane]

Yes it's supposed to spring shut. Turning the mains off as you have, eliminates the pcb.
Yes it's a pain taking time off work - some of us make early evening visits!

That is usually difficult with a service contract. However I think that the company in question were reasonably flexible.

Only thing I can think you could do is get a sulphidation filter put in the gas line, which will catch anything above 50 microns. Eventually of course that will block up, but it should only be one visit to clear it!

Well, that is actually a good suggestion. Since I have the old gas valve (one year old) I would like to peak inside and see if I can see anything wrong it it. The only problem is that I don't have a tool to remove the torx screws. However on the inlet side of the gas valve, there is a kind of a mesh filter which doesn't appear dirty.

Check that the gas valve isn't getting too hot for some reason, like a heat shield missing.

It does not have a heat shield on that side. There is one around the electronics. I will check that anyway.