glowworm Ultimate 40FF

Hi,
I have one of the above mentioned boilers and yesterday it decided no longer to be very happy. The 4 diagnostic neon lit (good sign), the pilot lit, but the main burner would not engage (no gas).
I turned it off, fiddled with it, and then it started working again. It was find this morning when I got up, and ok when I got home from work. However about 30 minutes it ago it failed to relight, and is now refusing to work!
I wiggled a few things as before, but no luck. There appears to be clicking from the internal theromstat of for the water heating temperature and the 4th neon flicks on and off.
This would suggest a fault with the ignition device, or the multifunctional control.
Anyone got any ideas? I am not too keen at fiddling with the gas pipes though!
Cheers, Matt
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On Wed, 12 Nov 2003 19:59:26 +0000, Matthew Ames wrote:

The diagnosis about the ignition or valve is probably on the right lines. Well you may need to get a pro to help you - they are not all rogues.
--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
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Either the HT lead is broken or more likely the pcb is knacked
--
geoff

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I wondered about the PCB, but 2 days ago when the problem 1st appeared all 4 neons came on, and a wiggle of the cables (nearer the multi-function control - the gas valve) seem to fix things. I had another fiddle last night after returning from the pub and it was working again, and remained working this morning as well.
What I did notice was that temperature setting knob / off knob unit seem to make a lot of clicking when it was not happy, and this tied up with the 4th neon going on and off. Eventually I found that by setting the temperature knob at the lowest setting seemed to make it work more realiably.
Cheers, Matt
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Matthew Ames wrote:

Does it have an airpipe operated switch for the flue? Mine does and when the sensor pipe became blocked it did similar to yours. Gunk from a corroded fixing had run down the side of the casing and over the hole, cleaning it out soon cured the problem.
--
James...
http://www.jameshart.co.uk /
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the
It has a fan in the flue, and that seem to happily fire up at the same point as the pilot light and stays running while the boiler *should* be running. I have a red and clear set of pipes that run down from the flue to the main control box and attach to some device on the side of it - I seem to recall this device has some pressure marking on it, in bars.
Am I thinking of the same thing, and if so what exactly should I be doing?!
Cheers, Matt
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Matthew Ames (news) wrote:

Mine got in that state and wouldn't go any further. The fan was running but the pressure switch at the end of the 2 tubes wasn't turning the next stage on. A bit of trial and error showed that it needed airflow through the pipes to (presumably) move a diaphragm in the switch and operate the switch itself. Blowing down one of the pipes proved this to be true. Where the pipes attach to the fan casing there's a short metal tube and it was here where the blockage was, actually it wasn't totally blocked but enough to cause the problem.
--
James...
http://www.jameshart.co.uk /
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but
stage
pipes
Pipes all appear to be clear, blowing and sucking gently down both pipes causes the pressure sensor to click - I guess I should really check that the circuit switches between NC/NO and NO/NC....
I have the popped out the PCB as well, and can't see any real problems, two resistors look as if they have got a little warm, as the PCB shows a slight degree of charring, but nothing serious, and they both still have the correct resistances of 470ohms, so I am getting to be at a loss!
Have checked all the connectors, and the thermal cut out , choc-block screws, so unless it works when I put it back together, I might have to give up and call a gas man to look at it :-(
Cheers, Matt
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Microswitch on the back of the pipe work seems to be working fine, so I am now at a loss. I guess that I will give glowworm a ring in the morning, and then after that i'll have to call someone out to look at it.
Only trouble is that I am away for the next week, so I shall have to leave a lodger to deal with it - either that or the lodgers can be cold till I return!
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I presume you're talking about the air pressure switch - if one of the pipes was blocked, then the pcb wouldn't generate a spark.
Bad solder joint or broken HT lead, that's my bet. Unless the main valve is sticking, although wiggling the wires wouldn't influence this.
--
geoff

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Yep... was the air pressure switch.... when I removed either pipe the whole unit shut down, so I know that was working.
All solder joints on the PCB look fine, but that may not be the case. What / where is the HT lead - is this the thin gray cable that runs up towards to the pilot lite?
Cheers, Matt
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It's the lead connected at the other end of the pcb to all the other flying leads, where the transparent case is angled off. If there is a break in the HT lead, it will spark, but won't flame sense
--
geoff

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I am with you...!
Infact I gave up this morning and called someone, but thet can't make it till I return from being away for a week - unless one of my lodgers is prepared to take some time off work!
I'll check that cable, but I when I spoke to the gas man (at some length - about 20 minutes) and after checking a few voltages, we came to the conclusion it was the main gas solinoid at fault - there was 230v across it, which suggested it should have been open and allowing gas to flow, but the main burner was not alight...
Cheers, Matt
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