puma fault

[kev1911]

hi all, this boiler works fine on dhw,however in ch demand it seems to fire then go out after maybe 10 seconds or so.
greatfull for all/any advice please.

thanks in advance

kev

 

[Agile]

Either you have a dripping hot tap or you are not waiting long enough for the diverter valve to operate ( or its failed )

Tony

 

[steve32]

i would be looking at the diverter valve
The way we test diverter is turn heating off, turn on hot tap run approx 2 galls hot water, tap on slow so boiler fires and gets to max heat, turn off tap pump on combi runs, when wax head on diverter reaches approx 80deg approx 1 min hot flow to heating should get hot (if you hold pipe be careful it will get very hot very quick) if pipe gets hot diverter is working if not then combi may overheat and go to lock out.
if diverter is ok i would then suspect pump

hope this helps

steve