Been having problems with hot water, after reading tips on here i replaced the diaphragm. Now i've got hot water but no heating! If i turn it on at the wall the switch moves up the fan starts & the burner lights for a few seconds then shuts down. 1st the boiler stops then the fan stops, no lock out!

Blue, January 2010

Well i've fitted the other diaphragm & a new thermister but still no heating. The boiler fires up then turns off! something seems to be telling it to shut off, but i don't know what or why!

blue, January 2010