Not related to my earlier “Best sequence for fitting a downstairs radiator” thread which thanks to some good advice went much more smoothly than I thought.

I have a radiator in dd’s room which is leaking. When the heating is off and the system is cold, it doesn’t leak. When the radiator is on and the heating is on, it doesn’t leak…or if it does it’s almost imperceptible and dries as quickly as it leaks. If we switch the radiator off and the heating is on, it leaks. Which all suggests to me that when the heating and rad are both on, everything swells up a little due to the heat and there are no leaks. Whereas when the rad is off, and the heating is on, the pressure against the closed (and colder on side of the radiator) valve is causing the leak.

We do need to be able to turn it off, as when it’s on full blast, the room just gets a bit too warm. Leak is from the fixing arrowed in my professionally marked up photo:

I’ve tried tightening it a nadge. Still leaked.
I’ve tried backing it off a bit and then re-tightening. Still leaked.
I don’t want to tighten it beyond the point where it does more damage to the thread and starts pissing out everywhere.

Is it at the point now where I have to isolate it, remove, drain and re-do the threads with some PTFE? Tbh, if I have to do that, it would probably be best to stick a TRV on there wouldn’t it? System is normal on/off pressurised combi.

Actually, just realised that I can’t isolate it (easily anyway) as the leak is combi side of the connection rather than rad side. 😡

This is going to be a drain-down and get a plumber isn’t it? 😐

PipeFreeze?

(I am not a plumber and have never tried this. If you’re planning to just undo whack some plumbers mate on the olive and a bit of ptfe on the threads and do it up then it might be worth a try. For replacing the whole valve then not)

Drain down, split olive off pipe, wire wool back to copper, reassemble with new olive. No PTFE on the pipe joint, PTFE on the radiator side.

I am not a plumber and have never tried this.

Neither am nor have I! 🙂

Bit nervous about being under that kind of time pressure. 😮

http://www.screwfix.com/p/fernox-ls-x-leak-sealer-50ml/23614?

Lazy man’s fix, which is how I did mine.

Drain down

the quick fix could be:

Turn the system off and allow to cool, get lots of towels, buy some Fernox water hawk (£6.19 from screwfix) and close the valve on all the rads so you only have the water in the pipes to worry about.

Put the towels all around to soak up the inevitable gush of water, undo the joint, quickly clean it and slap some water hawk on and then do it up.

Failing that close all the rads, drain the system as much as needed, drain that rad, replace valve if needed, new olive and clean up pipe (as above).

The only reason that it’s could leak there is that the seal between the pipe, olive and nut isn’t tight enough. Given that it’s a compression fitting it’s either not yet tight enough or has been overtightened and deformed too far. Personally, I’d tighten it a bit more and if it still leaks then just replace it, which would give you a chance to inspect the condition of the pipe and olive. A lock shield is easy to change, but you’ll need to drain the system down to a level lower than the rad. You might just need a few wraps of PTFE on the olive and reasemble.

If you can build a bike this is easy. You’re just worried because you’ve not done it before

So that fernox stuff…what, back the joint right off, apply fernox, then re-tighten?

EDIT: Oh right, I see now from andy’s post.

urgh leak sealer.

great at clogging up the bits you dont want to clog and still leaking….

Move house. Job jobbed.

Ptfe a few times around the olive and tighten up again. Always worked for me. (ex plumber)

there are 2 different types – one you put in the system like rad weld for car radiators and a jointing compound like I mentioned. Never used the former, would only do as a last resort on hard to access pipes and only as a stop-gap, but the joint compound I do use and it’s much better than using PTFE tape IMO. Dad used to always use PTFE tape on olives and threads but following advice from a plumber I got some of that water hawk and it’s a lot better and easier with less faffage. PTFE still needed in some cases/tasks.

I’m thinking I’ll try the PTFE route first (as I have some of that already).

So best way to avoid massive gush of water…isolate all other rads upstairs and allow system to cool down? I understand there will still be pressure of course but just trying to avoid three other rads worth of water that will be “above” the valve.

EDIT: then the fernox thread sealer if the above doesn’t work.

close all the rads so they hold their water. Drain the system down a touch, if the rads upstairs then just get the water down lower than that rad.

DD not on topic (flooring related), do I remember rightly that you are Bristol way?

PS if you do lose a lot of water then you may want to add some more inhibitor to the system.

Isolate all the up stairs rads. I’ve not worked on a combi system, but you might need to isolate the mains pressure feed via the boiler too. Any plumbers confirm this?

You can crack the rad side nut and catch the water in a baking tray underneath. You can often control the flow quite well be breaking the seal under the rad nut and using the vacuum via the bleed nipple on the rad. Still get towels.

DD not on topic (flooring related), do I remember rightly that you are Bristol way?

Yep. Email in profile if you need to ask anything.

Or deadlydarcy [at] gmail [dot] com

you might need to isolate the mains pressure feed via the boiler too

there is none to the heating side – it runs at a lower pressure than the mains.

Excellent, still at house planning and site clearing stage but wanted to check so I know where to go when the time comes.

if the boiler is upstairs then close the valves on the bottom of that too but don’t forget to re-open them 😯

if the boiler is upstairs

Good point… ‘course, I knew that already. 🙂

😳

pipe freeze. Looks like you have a long lateral bit of pipe accessable. you could even bodge a valve onto it for more time.

i’ve used it a couple of times and it always lasts longer then i need. even when i’ve done a bit of faffage on 22mm cold pipes. (mainly as i`ve no idea how to safely drain down the system)

turn off valve at rad, pipe freeze, undo, clean up joint – reassemble. easy!

I quite like plumbing

When you`ve finished dont forget to wipe that marker pen off your skirting 😀

And turn the boiler off at the wall switch

dont forget to wipe that marker pen off your skirting

😀

You made me look ya fecker.

Get a set of these. It explains what you do.
http://www.draytoncontrols.co.uk/DrainEasyKit.aspx

Then plug the tank and the breather to the tank and shut the other side of the rad valve down. Undo the valve to rad and drain about 1/2 litre, which is what you will only loose. The rad will hold the water in a vacuum too. When you have lost the water, then undo the leaky compression nut and remove the valve. I suspect that the olive is crushed and you may need to cut the pipe down a few inches and either solder a new one in or pipe and a compression connector. While the rad valve is off, throw in the bin and fit a Drayton TRV4 thermostatic valve. Bolt back up and then remove the plugs from the tank. Open the other rad valve and bleed and off you go. I did mine in the lounge recently after fitting 2 new rads , without draining down and its so easy.

Although a lot of people say PTFE is never needed on compression fittings, on an old fitting that’s not sealing properly, it’s sometimes the only way (other than a new fitting)

No point putting it on the threads though, the threads don’t create the seal, just the compression. A few wraps round the olive to create a “cushion” should do it.

(Jet Blue is better in my opinion, but not worth buying a pot to sort out one fitting when a roll of PTFE is pennies)

We had this with one of our rads on microbore. My FIL under the nut a little and lifted pull out the pipe a bit, cleaned it up then and then push all the way back in then tightened up. Seamed to work

Unfortunately you don’t appear to have an isolator on the pipe in the picture (not a dig, my house is the same and it’s crap that for a few £ plumbers don’t fit isolators)

ime, the pipe compresses a “washer” seated in the valve itself and it’s the washer which needs replacing (pence).

Some washers are fibre as shown above, some are rubber. I tended to use PTFE tape on the threads in the past, but if your washers are in good order, then ime, the PTFE is only “belt and braces” at best and not really necessary, imo.

If/When it was my turn, I’d drain the rad, replace the washer which is compressed between the end of the pipe and the valve and re-assemble.
This would be a lot easier if there was an isolator valve in the pipe, imo.
Good luck, I hope you get it sorted asap.

Haven’t read all the posts but….microbore is soft copper so olive can sometimes compress till you run out of thread. Release pressure off boiler, towels, close valve, undo fitting, finger over pipe end, wrap in PTFE tape, reassemble

Get a set of these. It explains what you do.
http://www.draytoncontrols.co.uk/DrainEasyKit.aspx

Then plug the tank and the breather to the tank and shut the other side of the rad valve down. Undo the valve to rad and drain about 1/2 litre, which is what you will only loose. The rad will hold the water in a vacuum too. When you have lost the water, then undo the leaky compression nut and remove the valve. I suspect that the olive is crushed and you may need to cut the pipe down a few inches and either solder a new one in or pipe and a compression connector. While the rad valve is off, throw in the bin and fit a Drayton TRV4 thermostatic valve. Bolt back up and then remove the plugs from the tank. Open the other rad valve and bleed and off you go. I did mine in the lounge recently after fitting 2 new rads , without draining down and its so easy.

This. Fit a TRV and you won’t need to keep turning it down.

Or you could do what I did, drain the whole system and fit TRVs on all the radiators, clean out any that are sludged up, fit a convenient drain cock to the lowest point in the system, then refill with Fernox.

Solo, I don’t mean to offend, but it seems like all your advice is wrong.

There are no fibre washers in radiator valves. They are compression fittings, with an olive.
The reason you don’t have isolation valves on every radiator is because they ruin the flow of the system.

nealglover – Member
Solo, I don’t mean to offend

No worries, my post is based on what I’ve encountered when I’ve had to address similar issues. Where I have seen the end of the pipe compressed against a washer and where the olive grips the pipe so that the nut can “pull” the open end of the pipe into the valve.

I’m not a plumber, far from it, so I could well learn something from this thread. I was just offering advise, based on my experience. I just hope the OP gets it sorted as easily and cheaply as possible.
😀

If you are going to back off the nut and put sealer or PTFE round the olive, remember that the part you want to seal is between the olive and the valve, not the olive and the nut. The nut is just there to push the olive into the valve, and (when the olive is new) squeeze it onto the pipe. So you need to pull the pipe out of the valve a bit to get the sealing material on the right bit of the olive.

The olive should seal without the need of ptfe, if the pipe and olive are good. Just a light smear of fernox lsx is all you will need for lubricity when bolting up and then will seal properly. Never put sealant in a domestic system unless you have flushed , cleaned and made sure that all ‘visible’ leaks have been resolved and the system still leaks. It may cause issues with sticking three port valves and pumps etc.

Are you absolutely, positively, 100% certain that it’s not leaking around the valve spindle and running down onto the compression nut?

Maybe worth pulling the knob off (!) to check – could just be that the gland on the spindle needs a tweak.

Tbh, if it got to the point where I needed to put a raw egg into the system, I’d probably call the plumber that lives two doors up. I wash his dogs massive blanket in my massive capacity washing machine every month or so. So he owes me a favour or two. So I think I’ll have a chat with him to see the best sequence for fitting a TRV. A new valve and lockshield is £7 from screwfix round the corner.

Again, thanks everyone for suggestions. This place comes up with some great advice sometimes. 🙂

I have fitted full bore service valves on pipes before radiator valves in the past where it wouldn’t look ugly. Let me shut off the rad and the pipework and lift the rad from the wall full of water. A 2200 wide rad full of water is pretty heavy though!

This is only a 600ish (I think) double…so pretty manageable. It’s also high enough off the floor to make it easy to get a decent size container underneath into which to drain it.

Btw, how does one get inhibitor into a combi system? 😕