a leaky valve joint on the radiator

[Softus]

You need to check for a common problem, which is a blockage on the cold feed into the system.

The simplest way to do this is to partially drain again (with the system OFF) and observe the level in the F&E cistern.

If the level does not fall then you have a blockage.

If it falls, then manually open all motorised zone valves, still with the system OFF, and then refill the system. Vent all rads. Vent the boiler, if it has a vent. Vent everyting that has a vent. Then vent a bit more, and make sure you get water from all rads. Take the end cover off the pump and check that you get a dribble of water.

Then turn the system on and check that the pump is rotating - use a small screwdriver in the hole left by the end cap to feel for the shaft turning.

BTW, when all this is over, you should add a chemical inhibitor to the system.

 

[Softus]

Remove end cover from pump - check that shaft is rotating by gently poking a small screwdriver in the hole.

 

[johnnycondom]

WELL
i thought i had cured the leak,but its still there ever so slight.
so i got me some boss white.
it says on tub to use it with boss hemp,well can i use ptfe with it and do i put the ptfe/hemp in the thread first before applying the boss white
thanx again for your patience and help with this problem
gotta cure it today as im flooring the room tomorro
thanx again, john

 

[Softus]

Did you get the radiators working again johnny? If so, what was the fault?

Regarding your leak, what method of fixing did you use the first time?

 

[johnnycondom]

yeah got em workin
looks like the diverta valve is shot (or very nearly)
cleaned all the rad valve contact faces and boss whited em
so i was told to do
was told the thread is only there to effect a seal on the valve faces by means of compression.
i'm only a humble blacksmith myself afterall
fingers crossed!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[Softus]

The first piece of advice you received on this topic was to use PTFE tape.

I strongly advise you not to use Boss White - if I'd realised that were going to do that then I would have say so earlier.

The problem with Boss White, apart from taking longer to apply and being messy, is that it's capable of being washed away over time - this is why hemp is used in conjunction with it.

However, it's not as good a technical solution as PTFE tape, to the extent that I can count on one finger the number of times I've used hemp and Boss White in the last couple of years, and it certainly wasn't the olive on the tail of a radiator valve.

Most times that I've found an overcrimped nut and olive joint it's because the seal wasn't good and someone kept tightening the nut in the hope of overcoming the problem. This rarely succeeds.

You'll have to drain again, at least partially, to remake the leaking joint. If the olive isn't in good condition then I'd replace it - use a copper one, not brass, because it will mould to mating faces more easily. Then use about five wraps of PTFE tape, overlapping the water side of the olive.

 

[johnnycondom]

hi softus
if you trawl back to the beginning of this thread
youll see that its not the olive on the copper flowpipe from the rad
BUT
the hexaganel nut thats on the rad where the leak/drip was
which screws onto the rad valve
anyways
upto yet its watertight
so hoping its end of
biggest worry is how much a diverta valve is gonna cost me
as well as a new pump in the near future
such an old system you see
i should say 20 to 25 years
bin looking round for a combi at the right price now for some months .thanx for all your help lads
john

 

[Softus]

hi softus
if you trawl back to the beginning of this thread
youll see that its not the olive on the copper flowpipe from the rad

Really? Your first post said this:

hi i seem to have a leaky radiator outlet pipe under the valve
it seems that the olive is letting the water drip from it

...and in another post you said this:

also its the joint under the valve NOT the joint into the rad

BUT
the hexaganel nut thats on the rad where the leak/drip was
which screws onto the rad valve
anyways
upto yet its watertight
so hoping its end of

I'm sure it is - until the Boss White shrinks and cracks and starts leaking again.

biggest worry is how much a diverta valve is gonna cost me
as well as a new pump in the near future

MZV - £80 ish
pump - £60 ish
inhibitor - £18
labour - half a day including draining, filling, venting etc., possibly more if there's a blockage.

bin looking round for a combi at the right price now for some months

Hm. That would cost you a lot more.