radiator driving me nuts with tapping All aspects of plumbing questions and answers, help, tips and information

[thefallguy]

Hi guys,

I'm at my whits end with my hallway double convector rad. When boiler running all I can hear is a contstant tapping, every 10 seconds or so. Then throughout the evening, presumaby when the pipes cool, the same tapping but not as often, say 20 scds. I know that pipes will expand/contract with heat but

I've listened to it and it's defo coming from the middle of the rad to the lock shield side. It's defo NOT coming from the flow/return pipes either above or below the floor.

I've recently had a plumber in to add another rad in down stairs loo. Told him about it. fired up the boiler after draining the system. stood there and listened - nothing. Sat down that evening in living room, heating been on a while and all you can hear from the hall way is the tapping from the rad....AARGH

Is the rad knackered? any suggestions? Thanks

[stoneyboy]

thefallguy,
Most likely that the jumper is loose in the lockshield valve but if you have TRVs look to see if they are dual flow ones. Single flow ones fitted on the wrong end can also cause knocking.
end

[htg engineer]

On some radiators you get little plastic or rubber inserts which sit in the radiator bracket between the bracket and the radiator - to prevent this.

I doubt it is the radiator valves. It does seem to be expansion.


htg