On Jan 17, 1:32*pm, John Stumbles wrote:
On Thu, 17 Jan 2008 05:27:01 -0800, Nick wrote:
I have a Worcester combi boiler which is about 11 years old. It is
under contract with B Gas. Recently it started blowing pilot out.
...
One of the things I have noticed is that when we used the hot water
before, it used to get really hot after 4-5 mins and it used to go
into a rest mode and started up again after a minute or so. Its not
doing that - it just trips now. I told that to the B Gas engineer and
he repleced the sensor but it has not made any difference. Is it
possible that the internal is not receiving enough air (fan maybe
faulty)?

I don't know this model of boiler but I'd suspect that the boiler may have
an overheat cutout which cuts out the pilot. If so I'd be looking at
either the sensor (too sensitive) or the circulation: pump, sludge in
system etc.

--


Might be that they've replaced the sensor and it still overheats and
they suspect it's because the heat exchanger has furred up meaning
there's not much throughput of water. If the main thermostat has
failed then this will also lead to an overheat situation and the
overheat stat does (and should) cut the circuit.