CH not switching on -> cold house = not happy wife HELP!

[RichSueJoe]

The central heating has stopped coming on automatically in the morning.
This system is serviced each October and has been working OK with no signs of any problem.
The system is on its own fused switch circuit, if this is turned off, the motorised valve can be heard whirring (normal), after a few seconds if switched on again the boiler ignites (assuming the stat is calling for heat) and all is OK, so it works, but not automatically - any advice is very welcome!! -
I believe the Centaurstat temp sensor works as there is still a click sound when manualy adjusting the temp setting.
The HW side works fine on its timer (tempus 7) + temp settings (on tank)
System details
Room stat = Horstmann Centaurstat 7 (CH + HW programmable), I have replaced the batteries (first thing I tried)
Tempus 7 electronic programmer HW+CH. The CH is set to 24hrs and the room stat is wired in via a ACL Lifestyle wiring centre.
Boiler = Baxi Bermuda Inset

System installed new in 1999

[zento]

Try putting your question on this website

http://www.plumbingpages.com/forums/ post it under WATER HEATING

[stanleyman]

I'm not sure how many programers you've got here but if you have a programable roomstat on a conventional system with another original programer also controlling the hot water then the heating needs to be set to 24 hrs to give control to the programable roomstat.

If you are saying it does not come on in the morning but if you turn it off and on again it works then it could be a microswitch in the three port valve.

[anth001]

My baxi boiler is the same, whereby you have to physically have to turn it on, and then turn it off again.

any ideas?