Pipework Noise When Rad Valve Off

[jaydebruyne]

I installed a 12kw electric combi boiler the other day.

Double checked what was the the flow and return from the manual of the old boiler before making connections to the new boiler.

Finished install, filled her up and all went well.

Was called back today as one rad, when you turn off the bidirectional trv it makes one bang in the pipework (back pressure on an unsupported pipe im thinking) and then a loud humming coming from the pipework under the floor and from the boiler.

Checked the rads and had the bleed a load of air. Checked the rad again and the noise went.

Can air cause this type of noise/ vibration in the pipework? At first I thought I piped up the flow/return the wrong way round and maybe the rad valves were one way. But the valve is bidirectional and the valves which are one way are absolutely fine. Plus I'm confident the flow/return are piped up fine.

Also on another rad, when switching the trv off makes a ticking sound for about 30 seconds then stops...???

 

[stevetheplumber]

easy to check ask customer to have the rad of before you arrive and then open the valve and see which end gets hot first

 

[kozak1968]

Check the pump speed. If Bi world Evolve TRVs from Mr Central Heating are fitted, these can make a noise if the pressure is above 0.25bar and fitted on the return.

 

[Rayzer]

I've had this problem on old trv the valve doesn't quite shut off and causes vibration. But strange to have 2 new one's do this. try changing trv's;-)

 

[jaydebruyne]

I've had this problem on old trv the valve doesn't quite shut off and causes vibration. But strange to have 2 new one's do this. try changing trv's;-)

Yeah I thought that, but I wanted to check here before recommending to change the valves. Cheers rayzer