In message , John Huckerby
writes
Last night my Vulcan Continental floor standing boiler stopped working.

The pilot light is on but will not fire. The Randall 4033 timer is old and
has been slowing down/stopping.

So, I had resorted to manually advancing it to an ON position which has been
fine for about a month.

I have just replaced the timer with a new one and the boiler still fails to
fire.

So, I guess that it was nothing to do with the timer.

The whole system is approx 23 years old.

What else could it be?

I presume that at that age it uses a thermocouple to sense the pilot
being alight, I'm not familiar with it.

Is the thermocouple on the pilot flame?

If so, replace the thermocouple - a few quid

If this doesn't work, then, it's probably the gas valve either stuck or
knackered (is the solenoid open circuit, are you getting volts to the
solenoid?)


--
geoff