Replacing radiator valves

[Steve Burrow]

Hi,

I'm having a combi boiler fitted and will be getting my radiator valves converted to Drayton TRV4s and lockshields at the same time. I'm told I can save some money on this if I fit the TRVs myself but before I spend the money on them I thought I'd check whether this is normally an easy job. I can understand the logistics of draining the system and removing the radiator and that all sounds fine, but are the ordinary radiator valves and the TRV4s normally the same size or am I going to get myself in a pickle with pipework that's then too long or too short to fit onto the radiators.

Has anyone had any experience of this? Thoughts welcomed...

Steve

[A.Lee]

Yep, looking at one now as I type this.The fitting is very close to, or is, the same physical size at the bottom of the rad, as the old 20yo valve it replaced, so yes, it should be a straight swap. The extra size is all above the inlet pipe on the rad, so shouldnt cause a problem, unless the rad is in a very tight position.

As for saving money with these valves, I'm not so sure. If one rad is getting too hot, I'd adjust the flow rate to it, so it is the same as others, or whatever I'd like it to be, these valves do it automatically, though at the initial 3 or 4 times the cost of a normal valve. Alan.

[spamlet]

"These valves do it automatically"

You wish! Got very fed up with having to take the top off and hit pin with hammer every day or two to get them to let any water through at all. Much easier to just turn the ordinary valve up and down as required - which is what people tend to do with the 'automatic' valves in any case - often wrenching off the end stops in an attempt to get it even warmer... And if you want to control the whole lot just put the thermo switch high up where nobody is tempted to keep turning it up.

S

[John]

If you are having to hit them then I suggest that either there is some seepage causing the stem to seize up. Do you have an inhibitor in the system?

Also - a bit of lubricant on the stem will help prevent sticking.

However, I accept that many people are not patient enough with thermostats and fiddle with them. Witness an air conditioned office with a remote control on the system - everyone will want a tweak every few minutes.

J

[Dave Plowman (News)]

What make? Like many such things you get what you pay for and shed etc own brands in my experience simply don't last as long as Drayton or other quality makes. So be prepared to change every 5 years or so.

[Dave Plowman (News)]

All rads should get 'hot'. A thermostatic valve controls the room temperature - not that of the rad. It works by switching the rad on and off to maintain this. But you should still balance the system with the lockshields even with TRVs to prevent uneven warm up throughout the house. See FAQ for details on how.

[Steve Burrow]

Thanks for the info... but my original question was whether radiator valves and TRVs are physically the same size, or whether I would end up having to move pipes around. Does anyone have any more thoughts on this?

Steve

[Heliotrope Smith]

It is most likely that your new TRVs will fit the existing pipework to your rads. Check that the inlet and outlet on your existing valves are the same length, if they are then you should have no problems.

[Dave Plowman (News)]

Buy one and compare? All TRVs are not identical as I discovered after my Wicks ones failed many years ago and had to be replaced. I couldn't get identical ones and had to modify the pipework. However, I'd say you have a good chance of Drayton TRVs being a direct replacement for your existing lockshields. You may have to change the stubs into the rads - but these come with the TRVs.

[John Rumm]

It is an impossible question to answer for sure since we don't know what your original valves are like. You may find that it is a straight swap, you may however need to do some slight bending of pipes, or you may even need to cut and re-pipe them. The other thing to check is if the new valves fit the existing tails screwed into the rad. There is more than one size of these. Note that you can get extension tails that can fit between rad and valve that can also solve some alignment problems.

[Roger]

The message from Steve Burrow contains these words:

It depends on what you have. I have certainly had to bend the upstands slightly when fitting TRVs. That was with a wooden floor so was quite easy. I think I might have struggled with short pipes coming up out of concrete.

[Steve Burrow]

Many thanks for the pointers... I guess I'll have to suck it and see.

Steve

[John]

Make sure you have the hex key for fitting the connector into the bottom of the radiator - I found that several of my old radiators needed the bottom connector replacing to get the TRV to connect in.

[Andrew Gabriel]

I found my 1/2" cold chisel was a perfect fit -- it was used for fitting the connectors to all my radiators.

[David Hansen]

On Sat, 28 Jul 2007 11:10:33 -0700 someone who may be Steve Burrow wrote this:-

Also check to see if Drayton has a web site with dimensioned drawings of the proposed valves.