In message , John Stumbles
writes
On Tue, 29 Jan 2008 21:52:47 +0000, Ian & Hilda Dedic wrote:


the last couple of mornings my relatively new (4 years old)
Worcester Bosch 24 boiler has failed to come on in the early morning.

Its full designation is worcester bosch 19/24 CBi

It may be only 4 years old but it's a pretty ancient design. Most of the
recent pre-condensing W-Bs have lightweight heat exchangers but this has a
cast-iron one.

The thermostat seems to be working ok and the timer unit seems to be
sending signals, but the boiler does not ignite.

At first I thought it might be the fuse to the boiler, so I changed
that and after turning the dial on the front to zero and then back on
again the boiler fires up ok and seems to work correctly all day.

Then last night, it was working fine just before I went to bed but
nothing this morning until I did the dial thing again.


So Have you guys (and gals) come across anything similar?

Had one of these a year or so back which sometimes wouldn't start up. In
that case it turned out to be a PCB fault and we got a replacement from
geoff (CET Ltd). IIRC the PCB was sometimes failing to generate HT for the
spark ignition. I don't know if this is a stock fault (but I'm sure geoff
will be along in a minute if it is)


not the commonest, but certainly a fault we see from time to time

I held back on answering the OP because there was no indication as to at
what point in the sequence it was failing



--
geoff