We have a Baxi Combi 80e boiler which fires up okay, but after about 20-30 secs the hot water goes cold. This problem does not affect the central heating in any way, which works fine. We have changed the hot water diaphram but this has made no difference, we have also cleaned the DHW sensor but this has still made no difference. Any suggestions, please?

Frank Lyons, May 2009

I have the same problem with my 80e. Were you able to fix the fault?

daveevans94, June 2009

Sounds like a blocked secondary heat exchanger. Remove descale and put back.

jack, May 2009

sounds like the dhw thermistor is faulty this is the first thing i would change it is cheapest to try first if it isnt that then with this model it is either the gas valve or the pcb, sounds like the gas valve is not modulating the burner pressure properly or at all if this is the case it is alot more expensive to repair.

xsyx, May 2009