How to fix a leaking radiator valve nut

How to fix a leaking radiator valve nut


in this video we’re going to fix this
leaking radiator valve it’s actually leaking from the compression nut at the
bottom there with this one you can actually just pull the cap straight off
some of them are held on using a small screw I’ve actually put a bit of kitchen
towel around there so that we could actually see exactly where the water is
coming from sometimes it leaks from the packing gland nut there which in this
case it isn’t because the top piece of kitchen roll is completely dry sometimes
it can leak from that Union and it’s definitely not leaking from there but
you can see from the tissue that it’s saturated we’ve definitely got a leak on
this compression nut I have actually tried to nip that up in the past a couple
of days ago and it is still leaking so this is a little bit difficult because
we can’t actually isolate the water without draining it down fully but
because this is a upstairs radiator what I’m going to do is I’m going to let
some water out of the radiator so that there’s no pressure in the system I’m
then going to close the lock shield valve there and then I’m going to undo the
compression nut, I’m going to wrap some PTFE tape around the olive and then I’m
going to tighten the nut back up it is risky doing this if specially if you
doing it downstairs because it’s quite a lot of water in some central heating
systems so I’ve ensured that the central heating is switched off can now remove
that because we know that it’s definitely leaking I’m now gonna place
an old towel around there I’m just gonna put a lot of blue roll at the back there
I’m now going to take a radiator bleed key because this radiator is on a pressurized
system we’re going to let out some of the pressure via the bleed valve
obviously if you’ve got a conventional heating system it is pointless
doing this because you’ll be there all day so just drain some water out and as you
can see that is absolutely filthy and I think the next thing I need to do is get
the system power flushed and get some inhibitor put back in there
because it definitely should not be that colour so the water is pretty much stopped
coming out of there we can now tighten that bleed valve back up can now replace the knob on there
I’ll just close that so what we’ve got now is the water that’s left in the
system hopefully that won’t be under a lot of pressure now so can now remove
the cap again and now need to hold the lock shield valve so that we don’t damage
that and then we need to take and adjustable spanner we just need to undo the
compression nut just at the bottom there so that’s now loose we should get a little bit of water
coming out of here as long as we don’t move the pipe I
shouldn’t get too much in order to make it easier to put the PTFE tape on, I’m
just going to wrap some around a spool from a sewing machine this makes it
a lot easier to apply it in a confined space obviously you can see it’s a
massive difference size between the spool and the spool that the PTFE
tape comes on now ideally we want the PTFE tape between
the olive and the actual fitting but that is going to be very difficult to
get it in there and what we don’t want to do is let a lot of water out of the
system so what I’m gonna do is I’m gonna take the PTFE tape I’m just gonna wrap
that around the olive the best that I can I’m also gonna get it just on the bottom
of the thread there so I’m now gonna break that off and then
I’m going to put the compression nut back up there and with a bit of luck when we tighten that
up it should actually stop the leak so again I’m gonna grab the lock shield valve
I’m gonna take the adjustable I’m gonna tighten the nut now that is pretty tight so I’m now
going to undo the lock shield valve again what we can do is tie a
piece of tissue around there and we’ll know immediately if it’s leaking because
the tissue will become saturated very quickly so I’ve now topped the boiler back up
and I’ve got the central heating back on and the radiator is now getting nice and
warm and as you can see from the blue tissue the leak has actually been
fixed what you don’t want to do is start moving the pipe or the radiator
once you’ve undone the compression nut at the bottom there or you could get
very wet very quickly it’s important to note that as soon as you undo that
nut you’ve got to be ready to screw it back on quickly just in case the water
does start coming out of the system this can be a risky job to do and if you’ve
never done anything like this before it may be a good idea to get a plumber to
do it for you either that or you can actually drain down the system to fix a
leak like this so I’d always recommend trying this first you can wrap some PTFE
tape around the olive if that doesn’t work you’re gonna have to drain it down
and then remove the pipe put the PTFE tape around the olive around the top of
the olive and then retighten the compression nut as a precaution I’m
going to leave that on there I’ll just keep an eye on that for the next couple
of days to ensure that it’s not leaking I hope you found this video useful if
you’re have and you haven’t done so already please subscribe to the channel

77 thoughts on “How to fix a leaking radiator valve nut

  1. It seems like I have something new to fix in this house every week!
    I hope everyone has a great Sunday 😉

  2. how effecient are these things , im assuming the water is heated using electricity, do they have a big impact on electricity consumption is what im realy asking i guess. i do like evacuted tube water heating , works even in cold climates no electricity required.

  3. The PTFE tip about wrapping round a smaller spool is brilliant!!! Thanks. I really enjoy your videos.

  4. The pipe leading to the rad isn't completely straight. Could this be a cause or contributer to the leak? Or leaking in general? Also do you have a magnetic filter on your central heating system? Just curious as water was murky. Great tip re: PTFE tape.

  5. Hadn’t thought of this, handy if you can’t drain the system down for whatever reason. Have you done a video on pipe freezing if you had to fix a leak on a mains pipe but couldn’t find or be able to shut the water off at the stopcock?

  6. At least in my house the pipework under the floorboards are free floating so when you into the nut there is the risk the feed pipe would drop out under the weight of the pipe and water in said pipe. It might be an idea to lightly clamp the pipe with an adjustable spanner or something first to reduce the risk of the pipe dropping out.
    Also for gravity feed systems maybe shut off the header tank out feed.

  7. Nice video as usual. That central heating really needs a flush. I have heard the new combi boilers don’t really like messy systems as it may clog some sort of screen filters.

  8. You've hit crude oil on that rad get a pump on it to BP – good video though thanks for ya time making it

  9. Looks easy but if I did it I would no doubt flood the village 😉 my mantra…if it can go wrong it will go wrong 😀

  10. I tend to use Hawk White Jointing Compound from screwfix around £4.50 a tub, its seems to be much better than using PTFE for fixing leaks from the olive.

  11. Had this happen a lot in a previous house that was fitted with micro-bore pipe. Every time you did the vacuuming, you would know a pipe and it would start leaking. I know copper is not cheap, but it is the worst idea when it comes to heating systems….

  12. Very unusual to get a sealed system with contaminated water at the top of the radiator .Considering you had the system power flushed once , you may have something else going on somewhere . Have you ever had to top up the system regularly because of a leak ,Introducing fresh water regularly will cause corrosion in the system . Are you bleeding the radiators regularly,You should not need to in a sealed system If you are it may not be air but hydrogen gas,their is a smell from it if it is but it will burn as well so be careful when you are checking . Closing down the automatic air vent on the boiler has the effect of holding the water in the system when the system is at zero pressure . ( Only gas Safe Registered people should work on boilers ) .

  13. I would just add to note how many turns it takes to close the locking valve down. Then, after repair, open it by the same number of turns. If the system has been balanced you preserve the status quo.

  14. Thanks for video and tips 👍👍. It's never ending sometimes with houses. It's not just you every time I plan on going somewhere I always end up doing a job😬. Such is life 👍👍

  15. Hope you are on the mend, great tip especially using the sewing bobbin 👍🏻. The trouble with pressurised systems is that they tend to find weak points on systems that were installed some years ago. My lad has an old ½” drain cock that just continues to weep and is near to a very old radiator that needs replacing. So delaying to the summer. I’d contemplate installing a Magnaclease or something similar, you should be able to install that yourself and would aid having that system power flushed. BUT I could be wrong. Happy Sunday. 😊

  16. I always enjoy watching your videos and your common sense approach of your repairs,thank you for sharing….cheers!

  17. Isn’t it worth shutting off all the rads in the house before you start just in the event that you dislodge the pipe you’re working on? That way all you would lose is the water in the pipework and not the rads

  18. No doubt the purists would question this but it is a valid repair, especially DIY. The only thing I would add (and not in any way a criticism) but leaks from olives can be due to an imperceptible alignment issue (such as a Hoover impact). Before nipping-up the olive the radiator fitting should also be loosened slightly. This allows a bit of flex in the fitting to allow the olive to seat properly when being compressed – then tighten the radiator fitting back up. Great video and we expect a follow-up with the CHS on dialysis.

  19. talking of flushing out a system how often should one do it with a combination boiler ? every 3 years maybe ? and how should it be done ? turn the boiler off and drain the system from the radiator furthest away ?and then refill the boiler with the loop hose ?( luckily mine is perm fixed with a valve tap )

  20. Thanks for this. I watch all your videos and appreciate the time and effort you put in. I have a pressurised system and our leak is coming from the gland packing nut (it leaks when the thermostatic valve is opened). My understanding is I can close the thermostatic valve, loosen that valve packing nut, and put PTFE tape under it to solve the issue. I don’t know if I need to drain down the system though?

  21. I had my plumber come and fit a spirotech deaerator to my system. My system already has inhibitor and a magnetic filter, but every cleanout of the magnetic filter resulted in ink black water being collected. Plumber says that oxygen in the system is responsible for 80% of corrosion, but the remaining 20% is galvanic corrosion which can be caused by ph being out of balance. In theory the inhibitor should take care of it, but it’s job seems to be a lot easier when there no oxygen in the water.

  22. A useful video; I don't have that type of heating, but it was interesting to watch the procedure.  I liked the genius tip about putting the PTFE tape on a sewing bobbin to make it easier to use in constricted areas.  The problem, though, is not everyone has a spare bobbin laying around unless they're married and their wife sews.  Not that many women sew here in America, anymore; it's become a lost art.  Overall, the only thing I would have done differently is use a combination wrench to remove/reinstall the compression nut.  I don't like using adjustable wrenches as they can slip or open up, rounding-over a fastener.  Thanks for sharing this with us.

  23. Hi I had a similar problem a few years ago and had to drain the system to get at the leak. While I had the system drain down, I fitted in line stop valves to all the radiators (both sides) so if I have a problem now I can easily isolate any radiator, this has been useful and makes it a doddle to wallpaper or tile behind a radiator.

  24. Couldn't agree more with the last comment regarding the sewing machine spool. When I think of how much tape I've messed up trying to wind it in a confined space.

  25. I have started using copper olives rather than brass. They don’t require massive torque to tighten and seal. In theory they would work hardened on multi changes of tails or valves but seen to seal much easier on original install

  26. Off tape didn’t work for me last time I tried it so I ended up cutting off the olive and replacing it with a new one and that’s twice I’ve tried to do it on a job and it failed due to compression on the property I was in at the time ok

  27. that was top tip about the ptf and I toataly agree that system hasn't put any enhbiter for a long time enjoyed the video

  28. Bleeding hell! (no pun intended) that system desperately needs some inhibitor in there! Nice video as usual btw.

  29. Great, "get me out of trouble video" and hopefully a permanent fix sometimes its just about having courage to have a go …..hope you are feeling well in yourself after your recent problems

  30. If you didn't have a sewing machine spool, I've seen a plumber just wrap his finger with the tape and apply it that way, although it could be awkward too and you'd need to used to it.

  31. Time to slap on a magna clean filter keep all the nasties out the system! Squeaky bum time when you loosen the rad valves or attempt to nip them up when full! I’ve had one go on me! Not great haha! Keep the videos coming mate! Always watched your channel!

  32. A great tip i used to do the same with good old hemp and boswhite.and a wedge down the side of the pipe just in case it dropped through the floorboards, cheers.

  33. I would ALWAYS pull the carpet back before attempting these jobs, I also AWAYS use my aqua-vac (Charles)! I do however like the sewing spool idea!

  34. By far a better fix is with hemp and paste, you don’t even need to de pressurise the system. We fitted a new Bosch 30Cdi to a working men’s club in Hemsworth, replacing an old conventional non- pressurised system. When we filled and pressurised the Bosch, 50% of the compression joints Leaked. Slack the back nut off and lower it down the pipe, it will dribble slightly but no gushing. Press gas paste up into the chrome fitting, pulling down slightly on the copper to pull the olive away. Then wrap in hemp and paste, allow the copper pipe back up to seat the olive and nip the fitting up. This worked first time every time, and with the heat passing through the fitting it will set hard and solid. Completed in 90 seconds per fitting.

  35. Just a quick question mate . I noticed you emptied a little water out via the bleed nipple .if you’re isolating the rad anyway why would this help ? Great video btw👍

  36. When you bled the rad and got that crap out I would have drained the whole system for a clean out . And a dose of leak sealer would have fixed that no problem.

  37. Use a pair of mole grips to gently grip the pipe under the towel, if the pipe suddenly drops out of the valve you’ll get a lot of water especially in an open vent system

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