Noisy Rads/Pipes

[KentNick]

I moved property on Friday and I have found a very annoying noise!

The downstairs rads are fine but upstairs is another story, the three bedrooms knock/tap repetitively every 10 minutes and it's hard getting to sleep although today I turned on the bathroom rad/towel rail to fully open which has now reduced the tapping to a single tap every 10 minutes which I can cope with. I have bleed all the radiators and they are all free of air. Any suggestions on what is causing this i cant imagine its just the pipes expanding as they stop when the bathroom rad is on? Just incase you need to know its a Vaillant turbomax 828e

Thanks in advance for any info!

Nick

 

[PlumbBobBob]

hi nick welcome to the forums. most probably the pipes are expanding and rubbing on something maybe where they pass through a joist. having the bathroom rad off probably made the hot water run through certain pipes which are tighter against something and opening the br rad made the run longer so more area over which heat can dissipate therefore less expansion in the pipes i think

 

[mountainman]

I'm with Steve on this.

 

[KentNick]

I really didnt want to have to take the floor boards up but looks like i have no choice, damn! Is it likely to be in just one place or through the upstairs?

 

[dancinplumba]

hi, as steve sez also have you got trvs on rads ? if they are one way valves, they maybe on the wrong side of rad this can cause tapping as they try to close
imo

 

[KentNick]

There are trvs but they are two way valves, i assume the only way to rectify the problem is to remove all the floor boards and find out where the pipes are tight/knocking against the joist?

 

[mountainman]

Think positive, you might find the problem at the first board you take up.

 

[warrington]

Before you take the floor boards! have you tried to fully open other lockshields as well! Especially the ones with TRV on! and some wd40 on TRV heads.There may be restriction causing noise!

 

[KentNick]

Before you take the floor boards! have you tried to fully open other lockshields as well! Especially the ones with TRV on! and some wd40 on TRV heads.There may be restriction causing noise!

You will have to excuse me but i havent a clue what a lockshield is? i know the trv is the thermostat at one end of the radiator, when you say spray with wd40 do they literally pull off? Im a complete novice with plumbing but like to think im capable of simple tasks

Thanks
Nick

 

[warrington]

other valve on your radiator, fully open it; you can remove the heads of the TRV you will see pin there. Spray some wd40 and push the pin in a few times slowly to get wd40 in!

 

[KentNick]

Ive just thought about it and when we moved in i turned the mains off to plumb in the washing machine then opened the mains fully, do you think that this could cause the problem and that i should just tweek the input on the mains tap?

 

[doitmyself]

the three bedrooms knock/tap repetitively every 10 minutes and it's hard getting to sleep

Do you keep the heat on all night??!!

Does the tapping stop of you open the TRVs to max?

 

[warrington]

No, mains has got nothing to do with your heating, you only need mains to re-pressurize your system when needed from boiler.

 

[KentNick]

Do you keep the heat on all night??!!

Does the tapping stop of you open the TRVs to max?

No the tapping is still there when we open the trvs to max, the only time is stops or settles is when we have the bathroom radiator on full.

 

[KentNick]

No, mains has got nothing to do with your heating, you only need mains to re-pressurize your system when needed from boiler.

Ok, i feel like a right blonde having a moment, my mrs thinks im going insane but its really annoying! I'll try the other options you have suggested when i get home and see if we have any improvement.

 

[KentNick]

one more thing which might give you a better indication is the the knocking/tapping noise comes from the side on the rads where the trvs are fitted just below the floor

 

[jtsplumbing]

As you say you have limited knowldge of heating are you sure that the TRVs can work in any direction (what make valves have you got)? will have arrow showing direction of water. this should be pointing to radiator, what side of radiator gets hot first ?

 

[KentNick]

The trvs have arrows in both directions and i believe the trv side gets hot first but will have to double check when im home

 

[mountainman]

Reversed TRV's in my experience only make a noise when they are shutting down when their temperature setting is nearly satisfied, at which point they vibrate.
I'm still firmly in the expansion noise camp.