How can I fix Myson Apollo 15/30 wall mounted boiler (serial 598677?

The boiler fires up and the hot water is very hot. However, it cuts out for the central heating and sometimes travels up the vent pipe into the header tank. Now and again, the heating will come on for an hour or so. Sometimes the boiler makes a rattling sound.
John, January 2007


done
No number. It only has a high/low setting. I have been alternating it to see what works.

john, January 2007
what number is stat on on boiler.?

hi-spec plumbing, January 2007
Tank is full of water. Water only gets hot when it comes out of expansion pipe. No silting. Pump on 3 setting

John, January 2007
its rattling cause its overheating. is the f/e tank in loft full with water ? is it hot water ? is it silted up in the bottom ? what speed is the pump on ?

hi-spec plumbing, January 2007
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