Open vented system noise

[herp_lee]

I have an open vented sytem and when the boiler knocks off a moaning and groan goes through the near by pipes. Can anyone point me in the right direction?

 

[zeebeedee]

Trvs fitted?

 

[herp_lee]

yes mate

 

[dave1]

Bypass open?

 

[herp_lee]

Thats what i need to check good point i over looked that.

 

[mountainman]

Pump over-run working ok!

 

[zeebeedee]

yes mate

If the old valves I'd look at renewing them, had a system about 6 months ago that was making a terrible racket, turned out it was when the trvs shut down.

Either that or look at the bypass, is there a rad acting as one?