Hi,

I have the above boiler and recently asked a question about replacing the diaphragm. Thanks to whoever answered it - the hot water is workign great now.

I have a slight problem now where the heating is not starting when the timer clicks on. I have found that if I run the tap for as little as a second the boiler will light and the heating will be fine - until the next morning when it is suppossed to come on again and I have to repeat the process.

Any help again would be much appreciated.

Thanks

Ritchie, February 2008

its prob the micro switch try bending it slightly

mark, March 2010

See the functional flow diagram fig 37 in your boiler manual.
Your domestic hot water microswitch may be failing. In one position it turns the boiler on for hot water, in the other position it turns the boiler on if the the CH thermostat, timer etc are go. Try giving it a little shove to see if it turns on the CH when it is acting up. If so it needs replacing, a fairly easy job to do. Take a photo on your mobile of the switch, or memorise what it looks like (there are two non interchangeable sorts on the 80sp). Take this to the spares counter. Its a cheap part. cut the leads to the old one and wire the new one in with a chocolate block connector or use the crimp bullets supplied. Remember to turn the electricity off before you work on your boiler.

c, February 2008