That time of year to turn on central heating. Hot water been working fine all summer, tried CH today but no joy. Pump was stuck so, thanks to advice on this site, managed to manually free it. Room stat seems to work. When turned up so it 'clicks', the pump is activated but boiler fails to fire up. When hot water is turned on, rads warm up. Can anyone advise on what the problem may be?
Potterton Kingfisher II boiler with new Thermsave TH0472 programmer.

TC, October 2009

You probably have a 3-way valve (look for 'T' shape in the plumbing)! There'll be a metal box on top. This houses the 'syncron motor' referred to. Note any Manufacturer's type numbers or other info. The motor can be separated from the plumbing parts quite easily.
You may have a motor-operated lever which you can operate manually. See what happens. If all springs to life, the motor's had it. If you're unlucky, the actual innards of the valve may be sticky/ broken/ blocked. Then you need a plumber. If you are lucky, SWITCH OFF EVERYTHING FIRST and carefully make a diagram of all wire colours and postions and take the motor to a CH parts shop for a replacement. Make certain you know where every wire colour connects to first!

Colin, December 2009

Thanks Tim,
Is the syncron motor part of the Nova 402906 gas valve and do I need to be CORGI registered for this kind of tinkering?
If not, where is the syncron motor located and is it easy to check and/or replace?
Many thanks for help.

TC, October 2009

sounds like your heating valve is not energising , check the syncron motor

tim, October 2009