Replacing manual radiator valves with TRV valves??

[Smk80]

Hi all,

I am thinking of replacing the old manual valves on my radiators with Drayton TRVs, however upon further inspection it would appear due to the size of the locking nuts connecting the old valve tails I'll need to remove these also and fit the tails that come with the new TRVs and the smaller locking nuts. I'm starting to think is it really worth it (seven radiators) as it would appear from researching that removing old valve tails that been there for years can be a right pain and actually ruin the female threads.

My main reason was to make the heating a little more economical. Do TRVs really make a difference and is it really worth it?

 

[Harry Bloomfield]

I fitted TRV's to all (but one) of my nine a couple of years ago, when I fitted a new boiler and later added all new controls. My system is 40 years old and I had no problems swapping them whilst the system was drained for the new boiler install.

It is important to understand that TRV's do not set the temperature, the room thermostat does that - rather they set a limit on the maximum temperature.

 

[JohnD]

yes, they are more economical, and also more comfortable as you can set each room to give the temperature you want. Unused rooms can be set very low (rather than off) which will help keep the room dry and prevent condensation and rust on the radiators themselves, or the valves seizing where they have been left turned off hard.

if you have wooden floors it is not too hard, the pipes have a bit of play on them unless they are jammed against a joist.

Most of the tails you can get out with a hand key. if necessary there is a tool that fits a socket set handle, but beware you don't rip the rad off the wall. In difficult cases you can lay it flat on the floor and get a portly assistant to stand on it.

If you get stuck you can put the old one back.

Also look at the RAS C2, which is a very good valve and IMO neater than the rather dated Drayton. The matching lockshield is very neat.

It can be a good time to take the rads into the garden and hose the old sediment out of them. Running X400 or similar for a couple of weeks beforehand will loosen it. Draining down in summer is the best time to clean the system (bale all the mud out of the header tank FIRST.

Once off, they are also easier to paint.

When you remove a rad, turn it upside down at once to prevent black water and sludge dripping out, especially as you carry it around

 

[Smk80]

Thanks - was there a useful tool you used to remove the old valve tails? A few of my rads are in tight spots so trying to get leverage might be tricky!

 

[JohnD]

I bought it several years ago. I have an idea people called it a "spud"

it has several sizes, arranged in a sort of taper, and mine fits a 1/2" square socket drive.

I probably got it recommended on here, so one of the pro plumbers will know.

the ordinary key is cheap and works on easy ones.

 

[JohnD]

here we are - radiator spud wrench

I think I tried to find one forged in chrome vanadium by a reputable maker, but couldn't.

I already have a good selection of ratchets and tommy bars for 1/2" sockets.

the old tails had a couple of internal nibs, so the tool is grooved to fit them. they usually have an internal hex in the throat.

 

[JohnD]

couldn't find the oldest post, but:

this is more often a problem if trying to undo one when the radiator is bracketed to the wall, and is very tight or seized, but it always applies.

the pulling force on the ratchet handle is not perpendicular to the axis of rotation (if I have the words right), as you have your hand on the lever, it is trying to pull the nut sideways, so is liable to slip off or bend it.

With a T-handle, and two hands, you can apply a rotational force staight down the axis of the nut, bolt or fitting.

 

[vulcancontinental]

I'm not a devout believer in TRV's although I have them myself.

I cannot ignore the report by Loughborough University however carried out some years ago.

They obtained temporary use of two adjoined identical three bedroom semi's with the same heating system in each. They put sensors in each room and monitored the performance of the Worcester combi, 7 or 8 rads in each.

Both houses had a room thermostat, one had TRV's in all rooms except the one with the room thermostat.

The findings showed a 12% saving with TRV's, more than you can expect from fitting a condensing boiler.

Importantly there was no furniture in the rooms obstructing air flow around the TRV's which is a common problem and impacts performance.

"Mission largely accomplished" says Johnson

"I got us largely across the Atlantic" says captain of Titanic.

'You cant always get what you want, you can't always get what you want, but if you try sometime, you get what you need' says Jagger/Richards