I have been having problems over the last couple of months with the
pilot light going out on my Glowworm SpaceSaver 50 Mk II boiler. It
started out happening every now and again and has got gradually worse.
What's happening now is that I can light the pilot light, and the
main burner fires up ok, but when the main burner switches off again
after a few minutes, the pilot light is also extinguished at the same
time. I am probably going to replace the thermocouple but is there
likely to be anything else I should be looking at ?

Thanks.

I am probably going to replace the thermocouple but is there
likely to be anything else I should be looking at ?

Personally, in that situation I'd change the thermocouple first and ask
questions later, if that doesn't fix it.

Christian.

"Kevin" wrote in message
om...
I have been having problems over the last couple of months with the
pilot light going out on my Glowworm SpaceSaver 50 Mk II boiler. It
started out happening every now and again and has got gradually worse.
What's happening now is that I can light the pilot light, and the
main burner fires up ok, but when the main burner switches off again
after a few minutes, the pilot light is also extinguished at the same
time. I am probably going to replace the thermocouple but is there
likely to be anything else I should be looking at ?

It's nearly always the thermocouple. The universal ones you can get in B&Q
will usually fit (they fit my Glowworm anyway). I have replaced about 2-3 in
8 years


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)

In article ,
Kevin wrote:
I have been having problems over the last couple of months with the
pilot light going out on my Glowworm SpaceSaver 50 Mk II boiler. It
started out happening every now and again and has got gradually worse.
What's happening now is that I can light the pilot light, and the
main burner fires up ok, but when the main burner switches off again
after a few minutes, the pilot light is also extinguished at the same
time. I am probably going to replace the thermocouple but is there
likely to be anything else I should be looking at ?

If you can remember, is the pilot light rather weedy compared to before?
If the boiler is lighting, it means the thermocouple is working. Could be
the slight pressure change as it lights blows the pilot light out.
Cleaning the pilot light jet would be my first try.

--
*Work like you don't need the money. Love like you've never been hurt.

Dave Plowman London SW
To e-mail, change noise into sound.

In an earlier contribution to this discussion,
Kevin wrote:

I have been having problems over the last couple of months with the
pilot light going out on my Glowworm SpaceSaver 50 Mk II boiler. It
started out happening every now and again and has got gradually worse.
What's happening now is that I can light the pilot light, and the
main burner fires up ok, but when the main burner switches off again
after a few minutes, the pilot light is also extinguished at the same
time. I am probably going to replace the thermocouple but is there
likely to be anything else I should be looking at ?

Thanks.

Can you please clarify what the "after a few minutes" refers to.

Do you mean that the main burner runs for a few minutes and then stops, and
that the pilot goes out at the same time? [I think this is the one you
mean]

Or do you mean that the pilot remains lit for a few minutes after the main
burner stops, and *then* goes out? [I wonder whether others have thought you
mean this]

If the pilot is going out with the main burner, it suggests that it's being
blown out by the draft caused by the main burner shutting down. This could
be because it is not very strong - possibly because its jet is partly
blocked by crud, or because it needs to be adjusted up a bit. [Does it have
its own regulator, to adjust the height of the flame?]

Does the pilot remain lit indefinitely if the main burner isn't running? If
so, it's unlikely to be the thermocouple at fault.
--
Cheers,
Set Square
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Do you mean that the main burner runs for a few minutes and
then stops, and that the pilot goes out at the same time?

Yes.

This could be because it is not very strong - possibly because
its jet is partly blocked by crud,

I could certainly believe this as I've been doing a lot of work
creating a lot of brick dust etc., but I did attempt to clean it last
night and it still didn't work.

[Does it have its own regulator, to adjust the height of the flame?]

I don't think so, but I will check again.

Does the pilot remain lit indefinitely if the main burner
isn't running?

Not sure I gave it long enough to be certain but this was certainly my
impression.

I bought a new thermocouple at lunchtime which I will be fitting
tonight (at =A32.50 plus VAT for a universal one it was silly not to).
I'll let you know if I still have problems after fitting it. Thanks
for all the responses.

In article ,
Bob Mannix wrote:
It's nearly always the thermocouple.

If the thermocouple was faulty, surely the main gas valve wouldn't open at
all?

The universal ones you can get in B&Q will usually fit (they fit my
Glowworm anyway). I have replaced about 2-3 in 8 years

I'm only on my second. In about 25 years.

--
*Change is inevitable ... except from vending machines *

Dave Plowman London SW
To e-mail, change noise into sound.

Well I replaced the thermocouple last night and cleaned the jet on the
pilot light again. It took quite a while to get the pilot to stay lit
but the flame was much stronger than it had been previously. It did
work well for quite a while last night and did stay lit even after the
main burner had shut down again, but there was one occurance of the
pilot being extinguished again. Not sure when it happened as I wasn't
watching it constantly. I relit it again and it seemed to work after
that and was still working this morning even though the timer had
switched the heating off and then back on again overnight. I'm
keeping my fingers crossed but I'm not yet convinced I've got to the
bottom of the problem.

In an earlier contribution to this discussion,
wrote:

Well I replaced the thermocouple last night and cleaned the jet on the
pilot light again. It took quite a while to get the pilot to stay lit
but the flame was much stronger than it had been previously. It did
work well for quite a while last night and did stay lit even after the
main burner had shut down again, but there was one occurance of the
pilot being extinguished again. Not sure when it happened as I wasn't
watching it constantly. I relit it again and it seemed to work after
that and was still working this morning even though the timer had
switched the heating off and then back on again overnight. I'm
keeping my fingers crossed but I'm not yet convinced I've got to the
bottom of the problem.

Well, the flame being stronger *has* to be the result of cleaning the jet -
the thermocouple wouldn't affect this.

I suspect that the root cause of your problem was a weak jet - so let's hope
it will now work reliably.
--
Cheers,
Set Square
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I had exactly this problem on a Glow worm 50,000 BTU 4 days ago - the Band Q
universal thermocouple did the trick (original part was £15 locally !!) but I
also noticed that the pilot flame was unstable and found a load of corrosion
had broken away from the burner frame and fallen down the burner tube,
partially blocking the pilot jet - cleaning this out also made the flame fairly
stable and adjusting the flame splitter so it engulfed the thermocouple tip
must have helped too.

Nick

In an earlier contribution to this discussion,
nick smith wrote:

I had exactly this problem on a Glow worm 50,000 BTU 4 days ago - the
Band Q universal thermocouple did the trick (original part was £15
locally !!) but I also noticed that the pilot flame was unstable and
found a load of corrosion had broken away from the burner frame and
fallen down the burner tube, partially blocking the pilot jet -
cleaning this out also made the flame fairly stable and adjusting the
flame splitter so it engulfed the thermocouple tip must have helped
too.

Nick

Geting rid of the crud would probably have worked without changing the
thermocouple.
--
Cheers,
Set Square
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Geting rid of the crud would probably have worked without changing the
thermocouple.

You may well have been right, but as I had it all apart an extra three quid was
minimal to save having to think about changing that.....

Nick

Well mine has been working fine now for nearly a week. I agree with
Nick, given the cost of a new thermacouple it isn't worth not
replacing it even if it may not have been strictly necessary.

In article ,
Kevin wrote:
Well mine has been working fine now for nearly a week. I agree with
Nick, given the cost of a new thermacouple it isn't worth not
replacing it even if it may not have been strictly necessary.

But you'd have to go and get one.

If the pilot light is reduced in size for whatever reason, sort that first.

--
*No radio - Already stolen.

Dave Plowman London SW
To e-mail, change noise into sound.

In an earlier contribution to this discussion,
Dave Plowman (News) wrote:

In article ,
Kevin wrote:
Well mine has been working fine now for nearly a week. I agree with
Nick, given the cost of a new thermacouple it isn't worth not
replacing it even if it may not have been strictly necessary.

But you'd have to go and get one.

If the pilot light is reduced in size for whatever reason, sort that
first.


Absolutely! And if you replace the thermocouple when there's nothing wrong
with it, but fail to address the *real* problem, you won't be any further
forward.
--
Cheers,
Set Square
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Hi
The thermocouple range is usually 8 to 15 mv and can be measured using
a candle for the heat, But changing a thermocouple has to be done
properly and what 99.9% of installers fail to do is to clean out the
gas block connection with a brass brush, The thermocouple tube has a
alloy outer olive (the neg?) this leaves oxide in the gas block
reducing the quality of the contact.
Maplin have a PCB cleaning brush which is ideal
Regards
Bob