Replacing a leaking PVC piping valve

[SantiSuk]

The larger PVC piping valve in this rather compacted array of valves and piping that lies at the foot of my water tower is leaking a few litres an hour and needs to be replaced. In the picture it is the valve at the top.

Looks like due to the compacted nature of the piping I may have to replace all the valves in view, plus most of the piping. If I have to do so I think I'll put the replacement two top valves on their down pipes or further along where there are longer lengths of plain pipe so I can cut them out more easily should they leak in future.

I know it's only a 500-1,000 baht DIY job, but does anyone else have bright ideas that may be slightly less wasteful on planetary resources?

1. If I cut between the valve body and the valve handle of the leaking valve I guess I might find some way of sealing up the resulting hole (then installing a new valve on that pipe's down pipe). Is that a runner - any ideas on how to seal a valve with its handle cut off?
   
2. Is there any piping that would fit glueably over a pipe connector? I'm thinking in terms of bodging* some kind of join from the top most T-junction in the picture (which would have a centimetre of old piping sticking out after cutting out the leaking valve but that is surely too little to make a replacing connection by itself.Again I would put a new valve on the down pipe to avoid putting unnecessary strain on "the old area" when opening/closing the valve.

FYI the piping was done that way in two stages by builders/repairers because a swimming pool and sprinkler system were added in at later stages after the tower was built. The valve in question is used quite frequently to turn off the water supply from tower to house water pump when I want to use village water supply to the house (through a separate tank under the tower out of shot).

*bodge = slang (in England only?) to do a build or repair rough and ready/cr&ppily/possibility of falling apart later )

[rawhod]

If it is possible to drain down the pipework adjacent to the valve, you could try the hot air gun method of softening the glue and pulling out the pipe. You have enough vertical pipework to the left to pull out the pipe from the valve.

https://www.youtube.com/watch?v=1DGRKMfUbwQ

Edited June 15, 2016 by rawhod

[RKASA]

There is no way to do it other then lay out something better and go for it. Make a drawing of what is needed and plan in for repairs - Unions and or compression couplings in the design will prevent future repairs from ending up looking like this. If something can be put together it should have a means of coming apart in a controlled manner.

PS these type valves will leak again and need replacement - count on it - some of them will become unusable, shuck, etc - Consider using real gate valves that will last.

Edited June 15, 2016 by RKASA

[KhunBENQ]

There is no way to do it other then lay out something better and go for it.

I don't have another idea.

A big cut and redo is necessary.

After step 1:

?: you seem to have another tank on a platform?

So plenty of space to the above?

And near the ? again another change in diameter?

A bit chaotic.

Edited June 15, 2016 by KhunBENQ

[KhunBENQ]

In the new installation Valve #2 could be moved upward to get some more space to mount without loosing functionality (just handling all three valves instead of only #2).

And then use a T-junction and straight to the pipe which is now on #3 (leveled to the tank outlet).

Edited June 15, 2016 by KhunBENQ

[KhunBENQ]

Consider using real gate valves that will last.

@RKASA: do you suggest such type?:

Edited June 15, 2016 by KhunBENQ

[manfredtillmann]

if you are going to do the mayor transformation suggested above, have a think about replacing all your pvc plumbing with polyethylene pipes and fittings.

pvc contains lead as a stabilizer, quiet a lot of it actually, which over time may leach into your water supply.

this is another reason why you should not use the heat - gun method to undo old connections.

but, given that most of thailands water supply appears to be piped through pvc perhaps it does not really matter, anyway.

[RKASA]

Consider using real gate valves that will last.

@RKASA: do you suggest such type?:

That is still a ball valve but better then the pvc type. That would be an improvement.

[KhunBENQ]

Just checked what gate valve means (I am not a native speaker).

This type is advertised as a gate valve:

Not seen often here.

http://www.sanwa.co.th/cds/index.php/en/product/sanwa/gate-valve/49-gate-valve-sanwa

Edited June 15, 2016 by KhunBENQ

[IMHO]

If it is possible to drain down the pipework adjacent to the valve, you could try the hot air gun method of softening the glue and pulling out the pipe. You have enough vertical pipework to the left to pull out the pipe from the valve.

https://www.youtube.com/watch?v=1DGRKMfUbwQ

I've used the hot air gun method more times than I can recall now. Works perfectly with the normal PVC adhesives on household plumbing.

[bankruatsteve]

Except for the cost, I agree a non-corrosive metal valve is probably the way to go. What I don't get is how to know a good PVC valve from not. I've have some PVC valves almost 20 years old and still working fine. But, a lot of others have started leaking within a couple years. I don't remember brand names but maybe that's something to consider with the PVC ones. (?)

[Crossy]

If it is possible to drain down the pipework adjacent to the valve, you could try the hot air gun method of softening the glue and pulling out the pipe. You have enough vertical pipework to the left to pull out the pipe from the valve.

https://www.youtube.com/watch?v=1DGRKMfUbwQ

I've used the hot air gun method more times than I can recall now. Works perfectly with the normal PVC adhesives on household plumbing.

I use a gas blowtorch, apart from the toxic smoke (needs good ventilation) works wonderfully.

[Crossy]

An off topic post has been removed.

[SantiSuk]

Thanks guys. I was not aware of the ability to un-glue the standard Thai farmer/plumber PVC pipework, so thanks for that. Might be useful here or in future.

I'm persuaded by the warnings that leaks are regular on these cheap ball valves and I do have plenty of room above the spiders nest shown in the photo to elongate the revised design. If I can find quality gate valves in the Ubon watsadu chains (all the usual suspects) or online, plus allied screw to glued pipe fittings I'll go for that.

Mind you, I have not been able to get my screw/compression ring fixings to work fully leak-proof on my pool filter to multi-port valve, so maybe I'd be better off going for a cruder glued in approach!

PS - after I posted I thought of an ultimate 'bodge'. Don't cut the ball valve in question - just stuff up the handle barrel with glue around its edges so that it is cemented open and leak-free (for an ill-defined period!). Put another cheapo ball valve in on the down pipe. Do it right when the next valve goes .

Edited June 15, 2016 by SantiSuk

[wayned]

I've also used a gas blow torch. Cut the pipe even with the top "T" and then on the other side of the leaking valve and remove it. Carefully heat the piece of pie that's left inside the "T" and pry it loose with a screwdriver enough to grab it with a pair of needle nose pliers then grab it and twist it out. Dress/clean the inside if the "T" with sandpaper and install the new pipe.

I've also seen it done without a torch by smearing a copious amount of glue inside the piece left in the "T" and lighting it (the glue will burn). Put the fire out and twist out the old piece. I've never tried it but have used the torch method successfully a few times.

[keeniau96]

I have pretty much the same piping assembly as you and had same leaking valve problem a few years ago. Did not know about the head and remove method, would have done that, so wound up with just cut and replace much of the assembly. I made the replacement assemblage with longer straight pieces so could cut out easy the next time. Also was careful to do the glue joints careful smearing with finger. So now that has held with no problems for over five years to date.

[longball53098]

I have not studied the piping assembly but so far no one has mentioned using unions ( preferably stainless steel ) installed in locations that would allow for easy removal of at least the complete valve assembly for repair/replacement or selected areas.

Just a thought!

[KhunBENQ]

The only unions found at our house is the water meter connection.

Water meter having male metal threads at both ends.

A rare part here although obviously useful.

If the OP considers a redo (cut) I would at least suggest to use a threaded part (elbow) for the two pipes going down.

So those will not need cutting if another repair is necessary.

[IMHO]

I have not studied the piping assembly but so far no one has mentioned using unions ( preferably stainless steel ) installed in locations that would allow for easy removal of at least the complete valve assembly for repair/replacement or selected areas.

Just a thought!

The problem with unions are - where to buy them?

The only ones I've seen are at pool supplies stores, and start at 1.5" in size. I did use them on my waterfall plumbing, and when re-doing my pool's main pump manifold.

If they made in TH unions, union ball valves and union check valves in "normal" plumbing sizes, i.e. 3/4", 1" and 1/14", I'd use them everywhere..

[longball53098]

I can buy this type union in various local sizes at Global House all stores or almost any local plumbing supply shop will carry cheaper galvanized unions. Hardware house has a really good supply of stainless fittings (304). I have many 1 inch unions at joints that expect to service on a regular basis.