Very Slow Radiator Leak

Bellycaster

As in the title, it is very, very slow, but I want to nip it in the bud.

What is this Radiator Part called? The Hex Head Part Screw Part, is it called a "Plug" or "Cap"? I can call in to a Plumbing Supplier tomorrow to get one.

https://i.imgur.com/TMPC1Jk.jpg

https://i.imgur.com/8ui92mh.jpg

I assume it's a job an idiot like I can do? I've not had any problems with Radiators before.

Thanks.

proggy

Hello Jon,

I'm pretty sure it's called a blanking plug.

spark240

proggy said:

Hello Jon,

I'm pretty sure it's called a blanking plug.

It is....it probably just needs some PTFE tape , the plug is probably fine  but if not...take the pic in ...theres only a couple fo sizes..make sure the heating is off , get bucket and a towel and just go for it.

You will need adjustable spanner or pipe grips...and some PTFE tape, get it with the blank plug , wrap a few turns of tape around the plug thread and wind it in...job done.

Bellycaster

Thanks @proggy and @spark240 I assume it is also recommended to turn the regulator to "off" as well as making sure the Heating is not on?

steveledzep

Agree with what's been said.  Before you release it, isolate the radiator by closing the valve and also closing the lock shield on the other side.  You're then only dealing with the water in that radiator, not the whole system.

ICBM

The problem will be if the thread in the radiator has pitted heavily with rust so the cap won't seal fully even with PTFE tape. In that case you may have to take more drastic measures...

Bellycaster

Aye, that might be the case @ICBM ;

Thanks also @steveledzep If it is ok when replaced, will the radiators need Bleeding? Obviously the Boiler might need a slight top up.

boogieman

Bellycaster said:

Thanks @proggy and @spark240 I assume it is also recommended to turn the regulator to "off" as well as making sure the Heating is not on?

You should get away with shutting the valves at each end of the rad. One of them will be a wheel valve or a TRV, the other one you’ll need to pull the cap off and turn it off with a spanner. Count how many turns it takes to shut the one with a spanner, you’ll need to open it the same amount when you finish or the system balance will go off kilter. 

I don’t think you’ll need to replace the blanking plug, it probably just needs resealing. As said above a couple of turns of PTFE tape should sort it. With the threaded side facing you, wind the tape round clockwise.  BUT the plug might have an O ring or fibre washer at the base, if it does and they look perished or cracked then either change them or get a new plug. 

Edit. Don’t forget to bleed the rad when you’ve finished the job.  If you’ve got a combi boiler you’ll also need to put some pressure back into the system via the filling loop. 

ToneControl

take the cover off before you start, otherwise you might damage it

On most rads, you slide up the end panel, and it pops out

ToneControl

put a bit of masking tape over that plug socket, not a major risk but nice to not get it wet

hywelg

Not a couple of turns of PTFE tape, more like a couple of dozen. 

boogieman

hywelg said:

Not a couple of turns of PTFE tape, more like a couple of dozen. 

Put that much on and it won’t screw in. 

A couple of turns should do it, it’s only needed to stop the water creeping along the screw thread. If it seriously needs more than that much tape then the threads are completely knackered and either the plug or rad are scrap. 

Bellycaster

Getting conflicting views about how many wraps of tape. We have a builder in at work who says about a dozen turns

what's with taking the cover off advice? The plug will unscrew with the cover on?

Confused.com

BeardyAndy

I've done a few installs and you put twice as much on as you think you need to!

My mates a gas fitter and i've done a few days with him (was thinking about a career change) and yes, a dozen or more wont be a problem. A couple like @boogieman suggests will be as good as useless!

Although, to be fair. Most new plugs have washers on so you dont PTFE them at all. Only the pipe fittings

ESBlonde

iirc those plugs have a rubber washer on them too, it's been a while since I fitted one. But in any event a 'few' wraps of PFTE and then run your nail gently into the threads so it goes in the rad easy. You can get little bottles of liguid PFTE, its a blue liquid so a spash of that on there too might be belt and braces, the stuff doesn't keep long term though so reseal the bottle well to get decent value in the future.

The idea of removing the cover is to get at it cleanly and avoid scratching the nice white panel with an adjustable nut cracker!

Bellycaster

Well, I think I managed that without fucking owt up, had heating on and off sice and seems OK. That PTFE tape is fiddly fucking stuff, it must have been hilarious to watch me trying to apply that. Although I am a Guitarist, I'm pretty cack-handed at a lot of things, Egg Whisks for Hands

The Plug did have a rubber washer on the shoulder @ESBlonde I still put a good few wraps of PTFE on though.

The leak was probably so small that it evaporated while the heating was on, but dripped out very slow once the Rad had cooled down.

hywelg

You do need to wind it the right way off the roll in order to keep it tensioned so it pulls tight into the threads. And the direction is important too so it doesn't start unwrapping when you screw it into unit the socket. 

And yes one or two wraps round in no bloody good at all. Twice as much as you think you need is good. 

ToneControl

However, the most important use for PTFE tape is to stop tremolo arms from swinging around too freely 

;-)