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
Anyone got any ideas? I am not too keen at fiddling with the gas pipes
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.
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.
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?!
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.
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 :-(
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
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.
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?
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...
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