Hammering and loud groaning in pipes, please help!

[Samantha]

Hoping someone may be able to help me.....recently I had a plumber fit thermostats to 2 old radiators in my house. Since these were fitted, when the central heating is turned on, the pipes make very loud hammering noises and/or moaning noises every now and then. The noise sometimes comes from two or three radiators (although it is usually one that is the loudest) or just one. When I adjust the thermostat on one of the noisy radiators it stops. Also, if you turn the hot tap on when the pipes make the noise, it also stops. I have a 4 month old baby who wakes up every time this happens and so I have taken to sitting in the cold instead.... Please can anyone help? I have had the plumber back numerous times but he seems to have no idea how to fix the problem. Thanks in advance.

 

[Dotty]

Pound to a pinch he's fitted them in the wrong direction!

I take it everything was nice and quiet before the TRV's were fitted?

 

[Ermintrude]

Do all of your radiators have thermostatic valves on by any chance?

 

[Simon F]

Hello Samantha,
assuming you have a combi boiler??
is the sound only when the thermostatic valve have closed? if you open to full (number 5) it stops?
Is there an auto bypass fitted?

 

[Samantha]

Yes, all was lovely and quiet before the new thermostats were fitted! Wishing I'd never done it! Yes, all the radiators now have thermostats on. These were the only two which didn't originally which is why I had them done. The plumber has been back and taken a thermostat off each of the radiators over a course of weeks to see if it makes a difference but it didn't.

 

[Samantha]

Hi Simon. The noise occurs when the thermostat is anywhere below 5 I think, when you turn it up to 5 it stops temporarily but usually starts up again later. I don't know if we have an auto bypass fitted, I'll ask the plumber.

 

[Samantha]

Yes, it's a Worcester combi boiler.

 

[Ermintrude]

Pound to a pinch he's fitted them in the wrong direction!

I take it everything was nice and quiet before the TRV's were fitted?

Most are bi directional ? If its a combi making noise after hot water due to pump overrun. If all trv's or the other rads are off its the pump forcing trvs open?

Simple solution, unscrew the head from the valve. ( chrome ring at base of plastic body) and noise should stop.

Ur plumber should have left 10% of boiler capacity uncontrolled I.e rads without trvs and at least one rad with lock shields on both sides so it cannot be switched off??

 

[Samantha]

Thanks ermintrude, will check this with the plumber.

 

[Ermintrude]

Take a photo of the valve he has installed and post it. Also u can check it ur self.

How many rads do u have? How many have the valves u can turn off? What boiler have u got?