Wrong TRVs!

[JBR]

I believe that at least some of our TRVs are on the wrong ends of the radiators. Yes, just one more bodging job in this house (although not by me, I hasten to add)!

I've been aware of this for some years but, as apart from some 'clicking' when the heating comes on, we haven't been bothered by it. However, since we've had a new (and bigger) boiler installed, the 'clicking' has become louder and, in fact, the radiator in the kitchen sometimes sounds like a powerful spin drier on a morning! Fortunately, I can stop the noise by slightly turning that particular TRV.

Consequently, the time has come for me to do something about it. Although I don't think it is doing any damage (please correct me if I'm wrong!) I think we're going to have to have them replaced now.

As I understand it, we can either replace them with 'non-directional' TRVs, or move them to (or put new ones on) the other ends of the radiators. I don't think there is any other option.

Am I right in assuming that, in either case, the heating system will have to be drained?

 

[ianmcd]

you wont need to drain the system , the Danfoss bi-directional TRV is a decent valve and not expensive

 

[Doggit]

Check and see what the pump speed is set to (assuming it can be slowed down)

 

[JBR]

you wont need to drain the system , the Danfoss bi-directional TRV is a decent valve and not expensive

Thanks, but surely if I remove the old TRV lots of water will gush out, even with the heating turned off!

Of course, I assume that the valve in the elbow will need replacing and not just the sensor in the top bit.

 

[JBR]

Check and see what the pump speed is set to (assuming it can be slowed down)

I'm afraid I don't know how to do this. The only external control is the temperature setting for heating (and one for the hot water). I assume the pump speed setting (if there is one) will be inside and I don't want to go poking about in there whilst it's under warranty. Even then, I'd prefer to leave that to Gas Safe people!

 

[ianmcd]

if you have an open vented system you can bung the F&E tank if it is a sealed system just release the pressure and you will get some water coming out but manageable with a towel and small bowl

 

[Doggit]

Have a look on the TRVs, and see if there is just one arrow on them, or two, and that'll show the direction the flow should be going. If there's only one arrow, and it's going the wrong way, then you'd need a plumber in to drain down the system, change the Trvs to the other end, or just fit new Bidirectional ones on.

Wjat is the boiler. You could have a chat with the installers, and ask them.

 

[JBR]

Have a look on the TRVs, and see if there is just one arrow on them, or two, and that'll show the direction the flow should be going. If there's only one arrow, and it's going the wrong way, then you'd need a plumber in to drain down the system, change the Trvs to the other end, or just fit new Bidirectional ones on.

Wjat is the boiler. You could have a chat with the installers, and ask them.

They are definitely the 'one way' type. I think that fitting bi-directional ones would be the easiest, but if I can do that without draining down the system I'd prefer that. Getting a plumber in would be more expensive, but at least I'd know it's done properly - I hope!

 

[JBR]

if you have an open vented system you can bung the F&E tank if it is a sealed system just release the pressure and you will get some water coming out but manageable with a towel and small bowl

I'm no expert, but I'd say it is a sealed system: a condensing combi boiler and no hot water tank or cold water header tank.

Obviously, I'd turn off the boiler, but wouldn't the radiator drain completely?... unless I can be very quick in changing the TRV!

 

[ianmcd]

nope if you drain the boiler the water in the rad will hold in a vacuum so as long as you are not taking hours a towel and a small bowl will suffice

 

[Nige F]

Use a Plumbtub drain tray from screwfix + towel

 

[rules&rulers]

Maybe it would have been good practice to replace the ancient (single arrow) trv's when the boiler was exchanged.

It can be done as a diy job, thou knowledge is required to prevent a water mishap situation.

 

[JBR]

nope if you drain the boiler the water in the rad will hold in a vacuum so as long as you are not taking hours a towel and a small bowl will suffice

Thank you.
Very encouraging.

 

[JBR]

Maybe it would have been good practice to replace the ancient (single arrow) trv's when the boiler was exchanged.

Yes, I wish I'd had the foresight to think of that earlier!