dripping valve next to hot water tank

[Davidt50]

I had my boiler repaired by British Gas yesterday but what I assume to be a relief valve at the top of the vertical pipe alongside the tank is weeping.

Can anyone confirm what this fitting it and how to sort it? I have reduced the boiler output temperature to 60 degrees and that seems to have reduced it.

 

[terryplumb]

Looks like an auto air vent. Can you show a picture in sharp focus ,close up ?

 

[kidgreen61]

Just needs tightening

 

[Davidt50]

Sure - I've just found my work light!

 

[Davidt50]

It doesn't appear to be loose. The water is appearing on the shoulder of the fitting, not between the fitting and the pipe. Can anyone explain its function? It appear to be part of the hot water rather than the boiler water system but I don't know that. I also don't know if one of the three Southern Gas technicians who've been here since Sunday would have opened it but I'm reluctant to use pliars to tighten it in case it shears.
Also, would the boiler water temperature affect this. I've reduced it but I'd like the radiators to be a bit warmer.

 

[terryplumb]

It releases air from the heating system automatically. If you can't tighten it ,try loosening it first ( caution have a towel handy water,possibly hot , will trickle out),then try to tighten up.

 

[Elkato531]

Its a manual vent not an automatic one. Tighten the cap a bit with a pair of pliers.

 

[Davidt50]

I've opened and closed it (inc case there was some crud causing the drip but that's made it worse and tightening it with pliars didn't help. Can I seal it termporarily?

 

[Elkato531]

There will be a small rubber disc inside the cap which gives the seal. It is possible that this seal has perished. The seal can be replaced but you will need to drain the header tank or bung the feed and vents to stop the water. For the moment, wrap in a towel to soak up leakage until you can tackle it or call in help tomorrow. If you have a pipe slice and a speedfit stopend, you could cut the pipe and jam on the cap. You will lose some water but if you're quick it will be minimal.

 

[Harry Bloomfield]

It releases air from the heating system automatically. If you can't tighten it ,try loosening it first ( caution have a towel handy water,possibly hot , will trickle out),then try to tighten up.

No that's a manual vent, and it looks as if someone has recently already tried to tighten it with pliers. So far as I know, the seal is brass pin, on a brass base socket, so might bed itself in to a better seal, by working it back and forth.

 

[Davidt50]

For now I've stopped it with bluetack and a plastic cap which may hold for a few days and I've shoved a towel under it in the airing cupboard . If someone has tightened it with pliars recently (apart from me after I took the photo) It could have been one of the clowns from British Gas who've worked on my boiler in the last few days.

 

[Davidt50]

The dripping got worse, despite all my efforts to reseat the valve, so in the end I paid a plumber to insert a stopcock in the pipe. Problem solved but, since that valve has never leaked before, I'm wondering why it should have started doing so immediately after British Gas (who I've never had in before except when they cut off and subsequently reconnected the supply to my street) have had their "engineers" in the house.

 

[JohnD]

It's possible it was previously sealed with years of dirt and limescale. Old leaks often seem to heal themselves like that but recur if disturbed.

I'd suggest fitting a new one.

 

[Davidt50]

Yes that's possible and the BG chap may be the first to have opened it for years. Replacing it will be the next job, probably with an automatic valve but, with a stopcock in the pipe, it's no longer urgent. I can still bleed it by opening the stopcock and the manual air vent.
My biggest problem still is the boiler making a lot of banging when it starts up but not always and often not starting at all, occasionally with an F24 fault, but then starting itself fairly normally an hour or two later.
The plumber thought it may just be air in the system following his partial draining to fix the pipe and suggested turning the boiler off, opening the drain valve and bleeding the radiators to clear any airlock.
However the banging was the problem that led me to take out a maintenance contract with BG followed two days later by an F24 and no heating which led me to book a repair from them before going into contract. That "repair" was last Sunday but the BG "engineer" just looked at it, cleaned the Magna filter, pronounced the water clean and said the boiler was OK (it had started working agan) and as I was due the first boiler service on Monday, did nothig else. The second engineer never did service the boiler as he found a slightly leakiing gas valve and disconnected the boiler (for £160) before booking a repair to that for Wednesday (est £340) The third BG engineer - who seemed brighter than the others- turned up on Wednesday only to find that engineer no.2 had ordered the valve but not the seals so couldn't do it. He came back on Thursday and did repair the leaking valve and reconnected the boiler (I asked him why it hadn't simply been isolated, I'm not the sort of idiot who would try to turn it back on, and he didn't know, very much implying that no. 2 wasn't the brightest star in the BG firmament. I then had heat again after three days of fan heaters but then discovered the dripping vent valve and I'm now right back to sguare one but hundreds of pound worse off.
I'm now thinking of cutting my losses, telling BG to stuff their maintenance contract, which is still in cooling off so I had to pay for their "engineers", and getting an independent to go over the system.

 

[Harry Bloomfield]

I'm now thinking of cutting my losses, telling BG to stuff their maintenance contract, which is still in cooling off so I had to pay for their "engineers", and getting an independent to go over the system.

Finding yourself, a good independent, is a much better bet, than being in a contract with BG. BG are generally known to be hopeless, and expensive, as you seem to be finding.

Me, I simply do not understand why you had a stopcock installed, to fix the leak from the vent, rather than just fitting a new vent/bleed valve. I have an identical one, in the very same location as yours, and for the same purpose. It's purpose is to collect any air, trying to pass through the heating coil of your cylinder. It only needs to be used occasionally, for maybe a few days after the system has been drained, and refilled. It should only need your fingertips, to open and close it, but it can jam, and you need some pliers, to grip it enough to open it, if it's not been opened in a while.