Banging Central heating system.....And my head!

[thebears]

I have a combination system and when the heating comes on first thing a load banging is heard behind the plasterboard walls between the radiators (as if where the pipe runs). The noise is getting louder, it then stops for a short while then will start again (presumably when the pump/boiler kicks in) The noise can also be heard when the system is off and cooling down. Any idea how to cure this. The system is relativley new <3 years, and also one of the radiators doesn't get fully hot! The one furthest away!

The noise is driving me up the wall!!

Please help.

 

[corgiman]

sorry mate but we have some more details like make etc

 

[thebears]

The make is an Alpha CB24, been told a pretty cheap boiler but works ok. The banging is all the time now. What else do you need to know.

Thebears

 

[oilman]

Sounds like pipes expanding and cntracting. You need to put some foam between the pipe and whatever it is they touch.

 

[ollski]

does the manual sat the boiler has a pump overrun...if so does it work?. It may be thermal shock.

 

[thebears]

The following is taken from the manual, it is the only referecne i can see to the pump running after the burner goes off, as far as i can tell it does work correctly.

The burner output then automatically adjusts to suit the system demand; as the temperature of the water in the boiler approaches that set by the adjustable temperature selector, the burner output is reduced. When the set temperature is reached, the burner is turned off. The fan continues to run for 20 seconds and the pump continues to run for three minutes to remove residual heat build up in the boiler before allowing the burner to relight

Why do plumbers install pipes etc without lagging them....Surely this would prevent the rubbing/banging and solve half the problems in this forum...

Dale

 

[ollski]

ok so you have a 3 minute pump overrun....does it work?

 

[thebears]

You can here something happening once the bolier flame goes out or you switch the heating off. I will check tonight when i get home. What does this do anyway?

Thanks for the advice
Dale

 

[oilman]

.......and the pump continues to run for three minutes to remove residual heat build up in the boiler before allowing the burner to relight.

As they say, if all esle fails, RTFI.