Bathroom towel rail TRV vibration

Linton

We have had a new bathroom installed,. Also our central heating pump has been replaced and the system flushed causing the system to run much more efficiently.

When the temperature in the bathroom rises causing the towel rail TRV to turn off it starts vibrating, often quite loudly. One time I thought the noise was a helicopter flying overhead. We have no problems with any other radiators. Adjusting the valve very slightly either on or off stops the noise immediately. I don’t think the vibration happened before the pump was replaced.

Is it simply a matter of replacing the TRV? Can they be faulty with these symptoms?

FreeBear

There is usually an arrow on the side of the valve body pointing in the direction of flow. If the valve is round the wrong way, it will make a racket (found out the hard way once).

There are a few valves that can be mounted either way round, but I've never seen or used them.

Linton

FreeBear said:

There is usually an arrow on the side of the valve body pointing in the direction of flow. If the valve is round the wrong way, it will make a racket..

There are a few valves that can be mounted either way round, but I've never seen or used them.

Thanks. There are arrows pointing away from the TRV on both connections. I assume that means the valve is bidirectional.

WIAWSNB

In that case it may be that the towel rad is simply receiving far too much flow.

The valve on the other end is a 'lockshield'. Could you try turning that clockwise to reduce the overall flow to the towel rail?

NB: first mark - say with a bit of sticky tape - the current position, and then count the number of clockwise turns it takes to close that valve off. Now open it - anti-clock - one full turn.

See how that goes. Ie, check the rad still heats up effectively, but hopefully quietly.

Please report back.

Linton

WIAWSNB said:

In that case it may be that the towel rad is simply receiving far too much flow.

The valve on the other end is a 'lockshield'. Could you try turning that clockwise to reduce the overall flow to the towel rail?

NB: first mark - say with a bit of sticky tape - the current position, and then count the number of clockwise turns it takes to close that valve off. Now open it - anti-clock - one full turn.

See how that goes. Ie, check the rad still heats up effectively, but hopefully quietly.

Please report back.

Thanks.  Sounds convinciing, it would explain all the symptoms.  However I may not have a lockshield valve:


Is this just a blanking cover or should the inside be rotated?  It looks like a special tool could be needed.  I can't move the outer part.

PS, this is on the inlet.  The TRV is on the outlet.
PPS I have found a large allan key that fits the hole.  I am able too turn it about 3/4 of a full turn.  It will also turn anticlockwise about 1.5 turns from the initial point.  So I will close it off by 3/8 of a turn and see what happens.

sheenas

That type of Lockheed requires an Allen keys. Look almost wide open from that photo.

WIAWSNB

Linton said:

WIAWSNB said:

In that case it may be that the towel rad is simply receiving far too much flow.

The valve on the other end is a 'lockshield'. Could you try turning that clockwise to reduce the overall flow to the towel rail?

NB: first mark - say with a bit of sticky tape - the current position, and then count the number of clockwise turns it takes to close that valve off. Now open it - anti-clock - one full turn.

See how that goes. Ie, check the rad still heats up effectively, but hopefully quietly.

Please report back.

Thanks.  Sounds convinciing, it would explain all the symptoms.  However I may not have a lockshield valve:


Is this just a blanking cover or should the inside be rotated?  It looks like a special tool could be needed.  I can't move the outer part.

PS, this is on the inlet.  The TRV is on the outlet.
PPS I have found a large allan key that fits the hole.  I am able too turn it about 3/4 of a full turn.  It will also turn anticlockwise about 1.5 turns from the initial point.  So I will close it off by 3/8 of a turn and see what happens.

That's different indeed! I presume it has a plastic cover over it when not in use?

But, if the inner nut does rotate both ways, then it suggests it does adjust the rad's flow - it is a lockshield.

With the TRV fully open, can you hear the hiss of water going through the rad? If not, do you begin to hear it as you close the TRV down?

Ok, if you can get to a 'hissss', then adjust the lockshield until you hear the note change. Even try opening the TRV fully, and then closing off the LS until it has a good hiss.

A towel rad will not require a large flow of CH water, so - when balanced - the LS would be expected to be very close to fully off.

You clearly know what you are doing, so good luck, and please report back :-)

(Even if TRVs are 'bi', it is always best convention to fit them on the flow, but hey...)