New Drayton rad valves leaking. Faulty or not?

[Mr. Clueless]

We got some rads delivered & new valves also. These Drayton valves: http://www.screwfix.com/p/drayton-trv4-white-chrome-trv-15mm-angled-l-s/34362?_requestid=22215 In case the link isn't allowed it's "Drayton TRV4 White & Chrome TRV 15mm Angled & L/S".

Plumber came out yesterday & changed one radiator & replaced the valves for that.
Then for the other 2 rads (that are already off the wall & will be getting changed) he just replaced the valves so he didn't have to do it midweek when he's out finishing the job.

Anyway he didn't put the actual TRV on to begin with. He put something else on, but it ended up leaking when we turned the heating on which he said shouldn't happen as you're supposed to be able to put whatever it was on there so you can decorate & not dirty up the TRV.

So he put the TRV on there & all appeared good.

But a few hours later the TRVs started leaking out of where it would connect in to the radiator. I wasn't at the house at the time but my wife & the plasterer there managed to stop it. When i got home the boiler pressure was at 0 so maybe that's what stopped it. Either way i did it back up to 1.25bar & turned heating on - no problems.

Get up this morning & again both TRVs are leaking out from where the pipe work would connect to the rad.



My wife called the plumber about it as it was initially leaking yesterday & told him the one in the hall was leaking but the other one she said was just a bout wet & wasn't sure if that was properly leaking or not (it is, but not as bad).

The plumber told her the valves are faulty & shouldn't be doing that & we should get in replacements so he can fit them when he lands midweek to fit the rads.


So thanks if you've read everything so far....

Q1: Is it normal for them to leak like this or not? It's not like a full flowing tap but it is leaking.
Q2: Chances of both valves being faulty would surely be very slim would it not?
Q3: So what valves would you buy in?



Q4: Additional pointer: We have no blanking cap on the end that would connect in to the rad. Does this make a difference? Should you be able to NOT have one there & expect no leaks or do you NEED a blanking cap fitted?

 

[Burnerman]

From what I gather, its leaking where the new valve tails screw into the radiator?
Remove them, add a good few turns of PTFE tape over the threads, belt and braces with some sealant and screw them firmly back in.
The decorators cap allows you to remove the TRV head and fully shut the valve off with the cap......even with the TRV on its lowest setting, some water usually passes.
Personally I always use the Drayton 4.
John

 

[PrenticeBoyofDerry]

Q1: Is it normal for them to leak like this or not? It's not like a full flowing tap but it is leaking.

If they have been fitted correctly, I would expect them not to leak.

Q2: Chances of both valves being faulty would surely be very slim would it not?

Slimmer than just one valve being faulty, but not to be completely ruled out, even if unlikely. The odds favour they have not been fitted correctly or they are not suitable for your pipework.

Q3: So what valves would you buy in?

The valves purchased are of a good quality, you need to know why they are leaking first, to assess what is required.

Q4: Additional pointer: We have no blanking cap on the end that would connect in to the rad. Does this make a difference? Should you be able to NOT have one there & expect no leaks or do you NEED a blanking cap fitted?

Not sure what you mean, do yo mean for isolating the tails of the rads for replacing rad valves?
Could you upload a picture of the leaking valves and associated pipework.

 

[dilalio]

When I remove rads for decorators to paint behind them, I never rely on just the rad valves or decorator caps to hold water back... Especially TRVs. I always "cap off" the valve with 1/2 or 3/4" brass blanking caps and rubber washers.
Also, on certain rads (especially towel rails) the valve tails are not tapered and ptfe tape just slides through... For these, I use hemp and paste as the hemp will swell to ensure water tightness.

 

[Nige F]

. For these, I use hemp and paste as the hemp will swell to ensure water tightness.

I cannae believe it and a smear of (boss white) paste on both the olive connections to the TRV - just a smear so it doesn't block the valve.

 

[dilalio]

Personally, I use this on the front of the olives

http://www.wickes.co.uk/LA-CO-Slic-Tite-Thread-Compound-With-PTFE-240ml/p/227184

 

[Agile]

I would agree that one cannot rely on a rad valve with an open output not to leak with either the head or the decorator's cap on them.

This is because the seal is just a simple metal to metal seal and is not designed to withstand a system pressure up to 2.0 bar.

The correct solution is to use a brass cap on the output.

Tony

 

[Mr. Clueless]

Yes that's the thing - initially he didn't fit the TRV, it had a cap there which i assume was the decorators cap & when i repressured the boiler i heard them shouting downstairs that it was leaking.

Anyway, here's the hallway one which is the one that is leaking most...

That didn't have that brass cap with a rubber bung on it. I've only just found where i'd put it so that's just been fitted 5mins ago which appears to have stopped the flow (time will tell).

Here's the one in the living room which was leaking a tad but nowhere near as bad...

Again, this also didn't have that brass cap on it. This one doesn't have a rubber bung as i can't find the other one that did have a bung.

Hope this helps.

The copper piping is i believe 10mm.

So pretty much i'm not sure whether to keep these as is & wait on the rads actually getting fitted, or buy in replacements & have these sent back to Screwfix & reported faulty.

 

[dilalio]

Dry all of those off with a towel and wipe your finger round the front and back of each compression nut (on the blanking cap and the painted stems of the pipework) just to be sure if the leak has stopped and, if not, where its actually coming from!
Pump up the system pressure and check them again!
It looks like you have 15mm yorkshire couplings "very" close to the nuts of the TRVs and I would worry that these give very little room for the valve to be properly home!

 

[dilalio]

Personally, I'd cut those off, rejoin upstream (in the floor) and bring up new copper with no joins to the valves. Gets rid of all that orrible paint as well!

 

[Mr. Clueless]

Thanks

It looks like you have 15mm end feed couplings "very" close to the nuts of the TRVs and I would worry that these give very little room for the valve to be properly home!

What is the cause here then? Bad fitment or is the TRV incorrect for this pipework?

With the last lot of rads the plumber himself supplied everything, but he let us down & didn't come to do the others he said he was going to so for these i bought in the parts & to be honest i don't have a clue.

If everything is at the very least the right stuff for the job then it comes down to workmanship & whether they are faulty or not.

 

[Mr. Clueless]

Personally, I'd cut those off, rejoin upstream (in the floor) and bring up new copper

Yeah he seemed to have done that on the lockshield side

with no joins to the valves.

This is where i show how i don't have a clue - surely the pipe work needs to join the valve otherwise water just pees out of the copper pipe as nothing is on the end of it?

I know that can't be what you're saying but like i said - i'm showing my lack of knowledge here now.

 

[dilalio]

It depends where they are leaking from! Do the checks with a torch and your finger... I'd say it's the lack of blanking caps as TRVs let by, as mentioned.

 

[dilalio]

You say the pipework is minibore (10mm?) then what I can see on the photos is not a 15mm coupling, it must be a 10-15mm fitting to suit the 15mm entry to the TRV... If so, my mistake, but it'd still be better to move that soldered join upstream, especially if he's done it on the lockshields.
And sorry, I meant no joins in the pipework coming up to the valve... It obviously needs to be joined "at" the valve

 

[Agile]

So pretty much i'm not sure whether to keep these as is & wait on the rads actually getting fitted, or buy in replacements & have these sent back to Screwfix & reported faulty.

Please read what we have told you!

The TRVs are NOT faulty! They are just not designed to close off the flow if not connected to a radiator.

The 10 mm to 15 mm adapter at the entry to the rad valves are perfectly satisfactory.

Of course, because 10 mm pipe is smaller and soft, then its better practice to have the change in size under the floor to look better and to avoid denting when vacuuming but that's not important and will not affect the operation at all.

Tony