Glow-worm fuelsaver pilot light concern

[benaround3]

Glow-worm fuelsaver 30 B

Hello

I have had some problems with the pilot light going out on my boiler. I have remedied it twice by replacing the thermo-couple but the first replacement lasted two years and second lasted only 4 months and now I am not even sure if the thermocouples were faulty in the first place, because something, I don't know what, happened at the time I was examining the thermo yesterday, and since then the pilot light has been burning much more energetically and the boiler is easier to light.

Before the "happening", the pilot flame did not envelope the end of the thermo couple, the flame was softer and it "floated" upwards, now it"jets" out to the side and covers the thermo end.
I dismantled the pilot jet , the pinholes seem clear, there was a little light brown deposit around the 2 pinholes which I cleaned off, maybe some of that had blocked the jet.
I noticed that there is an air vent just below the jet and if that had been partially blocked that would have the effect of weakening the flame back to how it was, but I can't see anything that could have been obstructing it.
I am not complaining that it now works, but am a little worried that the pilot may be burning too hard now, it makes a lot of noise, more than the main flame! It looks about the same size in the window as before, but comes out sideways rather than upward, as I said.

The only things I can think of that I could have done, are either :

I knocked the pilot while taking it off to inspect, and dislodged a blockage, or

while taking off and replacing the thermo at the gas valve end I also removed the unit between the main block and the thermo, where the wires from the safety cut-out go in on either side, and when replacing this without realising that it had a dual thread I had to turn it an extra half turn to get it back in the exact position it was before so the wires going in met up nice and easily, and I noticed on removing it again that this had caused slight compression of the little black washer that goes around the protruding bit of brass that fits inside the valve.

Sorry that I don't know the right name for these bits and pieces, and the system is actually working ok, apart from the noise of the pilot, it's not deafening, just definitely audible from anywhere in the vicinity of the boiler, whereas before it wasn't noticeable unlesss standing up close.

I believe from looking at manuals of later models, (Energysaver is the most similar that I can find onthe glow-worm site) that there is an adjustment for the pilot, near the pilot there are two slotted screw heads, one is grey/aluminium and nearest to the outlet of the pilot supply on the main block, the other is to the right of that and set about a centimeter deep and is brass. Is one of these to adjust the pilot and what is the other one for?

Can I get diagrams of this unit anywhere? I am an electronics test engineeer and would like to know more about the electrics.

With thanks

 

[LUNAT]

HI

sorry but you can only carry out work with gas parts if you are corgi registered and by reading your post i get a feeling that you not RGI.
so i cannot give any advice.
dealing with gas can be dangerous if you not sure about it .sorry.

 

[johndennis]

I've had similar problems, usually following high winds that blew out the pilot light. Luckily I have the original fitting instructions for this 27 year old normally excellent old-style 'steam-powered' (i.e. no digital crap) boiler which give a flow chart and voltage readouts to check the thermocouple etc. ( I will try to scan this and upload with a link later). However stuck in the back of this installation manual was a small pink card presumably made to be given to the user after fitting which gives a complete sequence of how to start the boiler. Imbeded in small type in this is the fatal statement.

"If pilot does not remain alight repeat lighting instructions again AFTER THREE MINUTES HAVE ELAPSED (their capitals not mine). If the gas control knob is turned to 'off' position at this stage, no attempt should be mde to force it back to the 'pilot' position until three minutes have elapsed."

Now of course this should have been stuck on a label directly on the outer casing next to the bloody knob but in the typically British way of engineering obfuscation i have never seen the card before and I doubt whether anyone else with this problem has so kept on trying to light it and deducing it was the thermocouple when it failed. I had intended to go out and buy a new thermocouple today before I read this card. Instead I followed the sequence and the boiler lighted first time! Of course people in this forum who have gone out to buy a thermocouple and fitted it would have found it to work when they got back after three minutes and so lack of these instructions has probably confused many people into unnecessary work.

There are two further points.

(1) I wonder how many current gas engineers know this and is this why they have to keep coming back to mess with repairs?

(2) I discovered the main reason why my boiler pilot light blew out in high winds was because some prat of an engineer took off the pilot light shield, presumably to make servicing easier for them! Previously I had also discovered after paying British Gas money for yearly servicing for a decade that the fitter who did mine left the burner unit free from its bracket to make his job easier and it was floating around inside the casing! Presumably it used to skip about every-time the gas was lit! It was not being able to trust them that made me begin to service my own boiler originally and I have done so for the past decade with little or no problems so far.

I am not sure why this starting sequence is SO important (perhaps a gas engineer on this forum can tell us?) but it did the trick with me and seems to account for those mysterious incidents above where the boiler wouldn't light and then later did.

Hope this helps. Here's the full sequence - edited for brevity;

1. Ensure that the thermostat knob is in the OFF position (The thermostat knob is the one you can seen when the bottom casing is on.)
2. Turn gas control knob (cream coloured plastic knob fitted to the gas valve) until pilot position is opposite the 'setting point' (in case you are a newbie this is the little round 'nipple' cast into the large gas valve beside the gas control knob)
3. Hold/press down gas control knob fully and keep down.
4. Click piezio-electric sparker.
5. When the pilot-light lights keep holding down gas control knob for approx 20-30 (recommend 30) seconds then release when pilot should remain on.

"If pilot does not remain alight repeat lighting instructions again AFTER THREE MINUTES HAVE ELAPSED. If the gas control knob is turned to 'off' position at this stage, no attempt should be mde to force it back to the 'pilot' position until three minutes have elapsed."

5. Turn gas control knob quarter turn anti-clockwise to 'on'.
6.Now and only now turn thermostat knob from off to say half-way or where you normally set it. Burner should ignite and all will be well.

Softly, softly catchee Glow-worm.

Hope this helps

John

 

[45yearsagasman]

All that effort to answer a 6 year old post.

 

[benaround3]

Yes, I posted this 6 years ago! I appreciate the effort you made, and it might have been useful, but I am now the proud owner of an Intergas open vent boiler, having read the recommendations for it on this and other forums.

And to LUNAT, thank you for the safety advice, there is no way I will be working on this myself.