Had new heat exchanger put in. When CH is switched on the boiler runs for a minute and cuts out, goes into modualting. Starts up again and runs for 30 seconds and cuts out. Demand for heating not there. C H flow pipe luke warm and the pump seems hot.
Have checked return valve mesh which is ok and no fault lights showing.

Tony, October 2013

Dam. Worked ok for a couple of hrs and its starting to do it again.
What could it be?

tony, October 2013

Kash. Fiddled with the pump which was ok and then Tool off the DHW casing off and replaced.
Some how the boiler has actually started. C H pipes boileng hot, upstairs rad a little cold

tony, October 2013

Kashm thanks for you reply. This only happens with the Central Heating. Shall I check the Pump by opening the Screw at the front of it? What shall I do?
By the way the dovertor valve was new with the heat exchanger as it was blocked with metal sludge.

tony, October 2013

check to see that any service valves are not closed. does it happen when using hot water or only when your trying the central heating. the problem seems to be there is no flow so the boiler is heating the water and reaching temperature so shuts of. screw the screw of the pump front to see if its rotating and not jammed. also check to see if the diverter valve is opening to let water into the heating

kash, October 2013