I have just moved into a 20 year old house, it has 15mm bore central heating pipes upstairs and microbore (?) downstairs. There is a constant knocking evey second for the entire time the heating is on (i.e. not just when the pipes warm or cool). Could someone explain the cause and cure without ripping all the floorboards up?
It appears to originate near the pipes under the radiator in the box room but it is hard to precisely isolate the source of the noise.
Any ideas?
Put the heating cold without the boiler on. If the knocking is still there then it is not expansion noises. It may be the pump or debris lodged in the pipe, or a loose rad valve.
Try setting your pump to a lower speed
That may screw up the balancing.
In article , anon writes
Have you considered calling in an exorcist?
i have a similar problem.
A Thermostatic rad value cuts off the flow when the set temperature is reached, then a knocking is heard in the pipes.
i assume this is a TRV getting stuck.
can this be fixed, or is it easier to replace a TRV?
IA
Have something to add? Share your thoughts — no account required.
Ask the community — no account required