I have a Baxi 105e combi boiler which was installed just over 3 years ago. During the summer period the switch on the timer for the radiators was in the off position. However, I have noticed that the pump kicks in from time to time for no apparent reason and the rads get luke warm. It does switch off after a short time on its own. I have even turned the switch over to hot water only and the problem still occurs. The only way to stop this occurring during the night is to swich the boiler completely off. Nothing has flashed on the fault finding panel so has anyone any idea what the problem could be?

Peter Rochester, September 2007

as mo saysthis is only to stop the pump from sticking when heating not in use.

gagz, December 2007

I have been told by a heating engineer that the pcb could be at fault yet the heating comes on and goes off at the set times on the clock without a problem. It's just this problem of the pump switching on when it shouldn't. It goes on for longer than a minute. Awaiting estimate for replacing the pcb.

Peter, September 2007

there is a small tank in the rear of the boiler which is used to keep a reserve of hot water. this is used when you demand hot water to get it to the tap quickly whilst the boiler is heating the cold feed. after you have used hot water or the temperatute of the water in the small tank drops and the boiler will heat it up again. when the tank is up to temperature, a small amount of water is diverted to the radiatiors to dissipate surplus heat. Irritating but a functional part of the system

rob, September 2007

Hi, this is not a problem. The Baxi 105e has clever mechanism that switches the pump on when the central heating system is not being used. This is to stop the pump from sticking. The pump runs for approx 1 min in every 24 hours of no use. Check your manual it mentions it within.

mo, September 2007

do you have a frost stat set to high possibly?? otherwise a possible thermister fault.

shonstar, September 2007