Towel Rail Noise

[Kallax]

Hello,

Thank you in advance for any help.

I have a problem with a noisy towel rail - when the CH turns off and the circulatory pump stops, the towel rail makes a loud screeching / gurgling noise.
It’s only for a couple of seconds but it’s each time the heating turns off and getting annoying now. It’s been happening for the last 3 weeks.
There was a leak from the gland nut on one of the valves, plumber tightened it and wound some white string like tape around it and no longer leaking. This was a week or so before the noise started.
Both valves are open about 1 turn. they were both closed more but plumber said try opening each a quarter turn when I rung him today but wasn’t sure what was making the noise.
Towel rail gets hot.
there’s no noise at the start of heating or during heating.
No new noises in other radiators.
I’ve bled all the radiators lots. Very slight air in towel rail and 1 upstairs radiator.
This towel rail has been there for 4 years.
System was drained and refilled with inhibitor added due to changing different towel rail. This was 2 months ago.

Worcester Bosch green star condensing boiler, Grundfos ups 3 pump, open vented system.

I’ve added photos of the towel rail and previous leak (from the right valve).

no noise coming from the airing cupboard where the pump etc is located. The noise is definitely from the towel rail.

Apologies for the basic info - very very basic plumbing knowledge only.

Thank you.
Sammy.

 

[cross thread]

Try opening the flow valve ( first one to get hot ) fully

 

[Kallax]

Thank you I’ll try that. So only open the flow valve and keep the return valve open at 1 turn? The flow valve is the one that gets hot first right? Thank you again

 

[Madrab]

Those valves may use O rings, so they may not be glands as such, the tape may not work for long.

If one or both valves are making noise then they are worn and without opening the valves fully they will continue to make the noise, how large is the system, number, average size of the rads? Hold the valves when it makes the noise and you should feel which on is creating it, that's the one you want to open fully.

 

[Johntheo5]

What mode/setting is the UPS3 pump on, if not sure, ensure the pump is running and post a picture of the LEDs.

How may rads?, do they have TRVs?.

 

[Kallax]

Thank you.
Ups 3 pump is on level 1.
13 rads. 2 towel rails.
All have TRV’s apart from 1 in the hallway where thermostat is.
Thank you for your advice so far.
Does it sound like the valve making the noise?
I’ll feel which valve is making the noise and open that fully.

 

[Johntheo5]

The UPS3 on CC1 will still pump at a 4.2M head, you could change to CP1 (constant pressure) which at a constant 3M may be adequate and reduce the noise level.

 

[Kallax]

Hi, thank you all for your replies.
I’ve opened both valves fully and although the noise is less, it’s still there when the heating turns off. Is the noise anything to worry about or just an annoyance?!
Thank you.
Sammy

 

[Johntheo5]

Have you tried CP1?, may be adequate at a 3M head, you can allways change back to CC1.