I sometimes have to open another hot tap before the boiler kicks in,sometimes it's ok.My boiler ia a Baxi condensing boiler which has recently had a new secondry heat exchanger and burner.It seems to me like there is not enough water pressure to fire the boiler but surely this would be all the time not just randomly..??Please help as this is driving me nuts..!!!

Derv., March 2011

Before the boiler kicks in for what? Hot water or heating?
I will assume hot water. What is the flow of water like, same as before? If not check the isolating valves on the boiler, May not of been turned on fully with recent work, Also what was fault, no warranty with work done? IF ALL valves are ok, but flow is less than it used to be, Could be the part was not installed correctly, Changing a heat exchanger would not normally affect water flow.
IF water flow is about same as before, Could be a problem with pressure sensor. Opening a second tap, would decease the pressure in the system a bit more.

Sheepdog, March 2011