intermittent heating fault?

Hi Ian,

Sounds like possibly one of the thermisters may be faulty and allowing the boiler to fire until the reaches its hight limit and safely cuts itself out.

They are certainly much cheaper than either pcbs or diverter valves.

If these were changed to cure this problem, seems like overkill to me, as if the boiler is firing pcb is more than likely fine, and if
your heating, then turn on dhw tap and get hot water the diverter valve is working

Tony
February 2008