I have worcester bosch boiler no problems until the weather is very cold and then the heating will not come on. Timer working fine, each time, the heating has to be turned off and the water run until it gets hot then the heating can be turned on again and this works everytime but is a real pain. In effect I think we are resetting to manufacturers settings each time to get it working.

warren, January 2010

Have a look for Worcester 19/24CBI Problems (Over Heating, Fail to ingite)? as your problem sounds similar to mine. You could try warming your board with a hairdryer to see if it fires.

I changed my printed circuit board and now everything fires up correctly on timer. I reckon there is some sort of minimum temperature thermal cut out. Even if something is sticking in the mechanical department e.g. relays, dry joints or gas valves. Warming up with a bit of hot air may be a good test to try and isolate the problem or at least determine if it is your board. I found a site that mentioned that some capacitors 'dry out' over time and there performance changes/fails. That was a bit too teccy for me to try but sounded a reasonable argument. (Planned obsolescence and obligation to call service engineers! £££!)

My temp control issues are ongoing but at least things warm up when timed to!

Good luck and hope this is a positive step. Keep trawling this site as I am finding useful info everytime I search. There are some really helpful people out there.

Rob C., January 2010