Hi I have a Baxi 105E
2 problems prob 1 hot water is about 88dg and no ajustment on control knob boiler fires for about 10 mins when demanding H/W then cuts out and re fires back up in seconds
Prob 2 water drips from blow off pipe when demanding C/H not when control on H/W only
thanks for your comments
Regards Steve

Steve, October 2009

Steve, did you fix problem? I have exactly the same I think. Central heating works fine. But when DHW is flowing leds light up until it gets to 80 degrees then flame goes out and leds start to drop. It then relights and so it goes on. DHW control knob makes no difference even if set to minimum.
Question is does it use a different sensor to monitor DHW and light the leds? I'm thinking it could be the sensor,.. but the leds are confusing me. Sorry for piggy backing on your question, but if you fixed yours, I'd be interested

Nick, November 2009

1: if temp control is not working, they are linked direct to pcb, boiler should generally still modulate on whatever temp setting you select but 88 seems a bit high=) if hw sensor is at fault you tend to get hot cold hot cold running water as the sensor does not tell the gas valve to modulate the burner down and results in the burner firing on full flame in bursts like 20 secs on 5 secs off etc etc.
2: If when you run heating the guage rises pretty quickly up and beyond 3 bar resulting in water being released, you have a flat (needs re-charged) or burst expansion vessel. They big red disc behind boiler, valve access from top, same as car valve, push pin in - little air=needs re-charge if you get water=needs replaced or a remote one fitting elsewhere.

ste, October 2009