Loud Bang from Boiler/Pipes when Central Heating turns off

[damo051078]

Hi,

I have just had a new Halstead boiler installed and it has been working correctly, however there is a loud bang coming from the boiler/pipes when the boiler switches off the central heating. We have no problem with the hot water.

The boiler is a Halstead 30HE combi boiler.

We have radiators on the system as well as under floor heating. There are 3 isolating valves on the hot water side of the central heating that are triggered by 3 thermostats we have in the house for different zones, separating our radiator system and the 2 under floor zones.

I was wondering if it might be air in the boiler somewhere as I have blead all off the radiator system and the noise is still there.

Any advice would be must appreciated

 

[cross thread]

boiler may require a by pass ,noise might be pressure causing a thump as zone valves shut, why not get installer back if its new ?

 

[damo051078]

Unfortunatly the installer is unlikely to come back as we had a few differences of opinion regarding some other work he did for us.

So looking around, this bypass valve would be connected between the flow and return of the boiler. I presume that this would be before all of the isolating valves that we have and would that be to keep the system pressure constant in the boiler.

At the moment it fluctuates flightly around 1 bar when each of the different insolating values open and close

Regards
Damion

 

[Padzster]

Did you find a fix for this as it seems I have the same problem, plus useless plumber.