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C

Chipdoctor

I have a pressurised system with a Gledhill inlet control valve. There is a red cap with 4.5 Bar written on it and at the opposite side of the cap is a black, octagonal 'bolt head'. There is a drip from that about every 3 seconds. I have tried to tighten it down but it appears stuck and I don't have a 27mm right angled spanner :) needed to get real leverage on it. Given that no plumber wants to visit at this time do you think I should slap some Fernox external leak sealer around it? Will it do the job given that the valve is managing full water pressure?
I gues I can live with it for a few days, I just have to empty the bucket regularly, day and night!
 
Stigster

Stigster

Esteemed
Plumber
That black plug seals on an o-ring type seal normally so unless it's really loose tightening it up won't help much. The other problem is you need to be G3 certified to work on this as it's part of the safety devices on the cylinder. It's a very simple and easy fix for a plumber to do as any 3/4" male plug will fit as long as it is sealed appropriately.

I have no experience with Fernox external leak sealer but having just looked at the product it won't do any harm. I do not know if it will stop a leak at pressure but it might so worth a go.

Because it is actually leaking I think it might be an allowable job under the regulations. I am not 100% certain on that though. I'm in the Channel islands and we have different rules to the UK.

If someone could please confirm?
 
SimonG

SimonG

Plumber
Water off. Slackened it off a turn or two. Wrap some ptfe in the gap. Re tighten. Water on. Get a plumber to sort it once this all blows over.
 
OP
C

Chipdoctor

Water off. Slackened it off a turn or two. Wrap some ptfe in the gap. Re tighten. Water on. Get a plumber to sort it once this all blows over.
Thanks Simon, I may do that. A problem is that of access. The pipework to cylinder distance is about 100mm so I can't get a molegrip or an adjustable in there. I made a short spanner yesterday which sort of worked. I am concerned that if I did manage to slacken it off with my home brew spanner I might not be able to tighten it up fully again and end up with a worse drip! I think I'll have a bash at the Fernox solution. Water off, dry it all and slap on the gunk. What can go wrong? As Mr. Clarkson is fond of saying.
 
Stigster

Stigster

Esteemed
Plumber
Water off. Slackened it off a turn or two. Wrap some ptfe in the gap. Re tighten. Water on. Get a plumber to sort it once this all blows over.
That's fair enough but if the combination valve is below the top of the cylinder it'll gush water if accidentally taken out, assuming OP is talking about the (unused) expansion relief port which has no check valve. Just want to make sure with OP before he goes undoing the plug.
 
OP
C

Chipdoctor

That's fair enough but if the combination valve is below the top of the cylinder it'll gush water if accidentally taken out, assuming OP is talking about the (unused) expansion relief port which has no check valve. Just want to make sure with OP before he goes undoing the plug.
It's the plug opposite the red cap with 4.5 bar on it. There's a 15mm pipe from that which goes out to the tundish. Your caution about the gush is well noted Stigster. I am going to cover it with Fernox gunk until I can get a plumber to fix it properly. Thanks to all.
 
Stigster

Stigster

Esteemed
Plumber
Yes, that's the tapping for connecting an expansion vessel there. Your expansion vessel must be teed in elsewhere, should be on the cold feed somewhere below your combination valve hopefully. Unless the cylinder has internal expansion (bubble top), we don't have any Gledhill cylinders imported at my location so I don't know if they do an internal expansion model.

If the leaking black plug is above the top of the cylinder it can be removed without leaking much water, providing the water supply is turned off and you have opened the lowest tap in the house to depressurise the system and empty the pipework as much as possible.

If the black plug is lower than the top of the cylinder, the cylinder will need to be drained to attempt repair, excluding trying Fernox external leak sealer which will be fine to try whatever. I appreciate it's possible to partially unscrew the black plug and try to wrap the thread a bit and make a shoulder from tape and do it back up again to make it seal, however my nerves couldn't stand doing so many years ago back when I was a DIYer and didn't have all the right kit. You may feel different of course.

What if the leaky plug is cracked and it just gets worse? Small leaks so often turn into bigger ones when you mess with them that little bit too much. Depressurise your system by turning off the cold feed to the cylinder and open a hot tap. When it stops running try your external repair. I have no idea if it will work but no harm done if not.
 
SJB060685

SJB060685

Yes, that's the tapping for connecting an expansion vessel there. Your expansion vessel must be teed in elsewhere, should be on the cold feed somewhere below your combination valve hopefully. Unless the cylinder has internal expansion (bubble top), we don't have any Gledhill cylinders imported at my location so I don't know if they do an internal expansion model.

If the leaking black plug is above the top of the cylinder it can be removed without leaking much water, providing the water supply is turned off and you have opened the lowest tap in the house to depressurise the system and empty the pipework as much as possible.

If the black plug is lower than the top of the cylinder, the cylinder will need to be drained to attempt repair, excluding trying Fernox external leak sealer which will be fine to try whatever. I appreciate it's possible to partially unscrew the black plug and try to wrap the thread a bit and make a shoulder from tape and do it back up again to make it seal, however my nerves couldn't stand doing so many years ago back when I was a DIYer and didn't have all the right kit. You may feel different of course.

What if the leaky plug is cracked and it just gets worse? Small leaks so often turn into bigger ones when you mess with them that little bit too much. Depressurise your system by turning off the cold feed to the cylinder and open a hot tap. When it stops running try your external repair. I have no idea if it will work but no harm done if not.
As sound advice as it is Stigster remember this is a G3 requirement and should not be tampered with by anyone without the qualification. I appreciate its just a weep but the last thing the OP needs is this backfiring.
 
king of pipes

king of pipes

Esteemed
Plumber
Gas Engineer
Very risky if your stuck for space and don't have the correct tools personally I would try some of this until you can get a G3 in to sort it . Kop
 

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OP
C

Chipdoctor

Very risky if your stuck for space and don't have the correct tools personally I would try some of this until you can get a G3 in to sort it . Kop
Stigster's comment about the small risk of a cracked plug confirmed my intention not to mess with it further.
I applied the sealer and left it overnight to cure but, it didn't work which is a (expletive deleted). Now to ring every plumber in a 20 mile radius to find one who wants a simple fixit job.
Thanks for all your support and advice.
 
king of pipes

king of pipes

Esteemed
Plumber
Gas Engineer
Stigster's comment about the small risk of a cracked plug confirmed my intention not to mess with it further.
I applied the sealer and left it overnight to cure but, it didn't work which is a (expletive deleted). Now to ring every plumber in a 20 mile radius to find one who wants a simple fixit job.
Thanks for all your support and advice.
Where are you in the country ? Plenty of good guys on here post in the appropriate section many are still doing emergencies
 
OP
C

Chipdoctor

Where are you in the country ? Plenty of good guys on here post in the appropriate section many are still doing emergencies
I'm about 12 miles south of Bath, west of Radstock and would welcome a message. I will also post in the 'Find a plumber section.'
 

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