Pilot light is lit, Boiler won't fire

[aki]

I got me a wee problem...

I have no Hot water, and no central heating... There are a 4 rads in my flat, a thermostat in the front room, a clock/ timer for the HW and CH, a boiler, and a hot water cylinder. A fairly conventional system. There is no indication of what type of boiler it is other than the fact it is a wall hung boiler with Honeywell controls on the boiler.

The problem I'm having is that the pilot light on the boiler is lit, but will not fire even though the clock/ timer is on CH constant and HW constant, and the thermostat is on high.

My uneducated guess would be that the clock is not communicating with the boiler?!? Should I replace the clock and or the thermostat?

Any help would be appreciated.

regards.

 

[MANDATE]

I would think there must be a 'gas valve' that is operated by a solinoid in order to light the boiler. It is possible that power is not reaching the solinoid, but that could be due to blown fuse, faulty timer/programmer or faulty 'gas valve'. I don't see the point in changing anything until you've carried out some tests.

 

[aki]

What tests would you suggest?

thanks in advance.

 

[croydoncorgi]

If the boiler is completely silent, then it could be a thermostat or clock fault.
If there are any of the normal whirrings or whooshings (fan or pump noises) it's probably a fault in the boiler (or in a separate pump if there is one!). With the amount of information you have given Not even the model of boiler) further diagnosis is impossible. Quicker to Get Someone In, starting from here.

 

[aki]

Yup the grundfos is whirring away fine... but the boiler just doesn't want to fire up at all... and also it appears as tho the immersion heater is hard wired on to be constantly on?!?!?

 

[aki]

Sorry misread your last...

The grundfos pump is not in the boiler & the boiler is completely silent.

The clock does seem to activate the grundfos fine, but has no effect on the boiler.

 

[MANDATE]

Presence of electrical power at the right places at the right time, ie is power going in the timer/progammer and does it arrive at the gas valve when hot water is demanded, if it does then why change it?
Thermostats are just switches so the operation of them can be checked with a meter.
I may be wrong but my logic suggests you need gas valve to open and if it did then boiler would flash up. So why does it not open? maybe solinoid on valve faulty (check it) maybe power not reaching valve (check it).
Maybe boiler stat faulty (check it) may be cylinder stat faulty (check it).
By all means check the out put from the timer and input if need be.
Perhaps boiler has gone to lockout mode (re set) Perhaps the fuse/mcb has blown.
I don't know what else you have there that could be faulty, perhaps an air pressure switch or a 'circuit board'.
You just have to eliminate everything you can till your left with the culprit