Water Line Into Pool

[ricelg]

Hello,

I am a new home owner and am glad to have found this site as this is my first time owning a pool also. The attached picture shows the plumbing of an existing water line we've used to fill the pool when it gets low. Yesterday the plastic cap on the right began leaking when I turned the black cap on to fill the pool up. I'd like to replace the cap obviously. Is this common hardware found readily at Lowe's/HD? Does it have a "name"? If I've got the black cap turned down, then in theory no water should be coming through the line so I shouldn't have to turn the water off to the house to repair, yes? Any ideas what specific function the cap serves other than closing the line?

Thanks!

 

[Divin Dave]

Hi and welcome to TFP!
that "black cap" is part of the backflow preventor. That whole assembly from the pipe off the spigot to the PVC is actually called a "Pressure Vacuum Breaker" valve or PVB and they are used primarily on lawn irrigation systems.

The purpose of it is to prevent water in the pvc pipe from backflowing into our home water supply just in case a massive water line breaks. A massive break could cause a suction action taking place and could conceiveably suck pool water into the water lines in your home. blah blah,

Most likely its an O Ring under the black knob that has sprung a leak. Its fixable, but by the time you find out what size O ring you need and then find one and put it all back together, its hardly worth $ saved vs the time. At least IMO it is. You could replace the whole thing if you wanted to. Its an easy DIY. (optionally, you could just get rid of it and replumb from the spigot to the PVC, depending on your feeling about water being sucked in from the pool. A 2 way spigot splitter and couple of fittings and viola....).

Anyhow, they should be available in Lowes or HD or a sprinkler supply store and online. Just get whichever size fits the pipes you have.
There are several designs of them, so dont fret if you can't find one EXACTLY like that one. If you want to replace it, just get whatever fits your pipes.

Most folks dont have a PVB on their fill lines. Its usually not a building code requirement since the autofill is not plumbed back to the city main supply line, but lots of plumbers install them anyway.

 

[ewkearns]

Is this common hardware found readily at Lowe's/HD? Does it have a "name"?

Example from Home Depot, and they have a fairly wide selection...

Click here.

If I've got the black cap turned down, then in theory no water should be coming through the line so I shouldn't have to turn the water off to the house to repair, yes? Any ideas what specific function the cap serves other than closing the line?

Yes, if you repair. No, if you replace.

IMHO, there is some definite pucker factor in homeowner replacement of this unit. You are close to a wall, so valves are going to have to be arranged to be on the outboard side, regardless of how they are originally assembled. The last thing on earth you want to do is upset the "T" fitting at the hose bib, unless you have complete and unfettered access to the back side of the plumbing. So.... to remove the PVB you'll have to saw the 3"-4" vertical nipple and the pipe on the right.... then back out what is left of the nipple. Reassembly will require at least one union.... I believe the pipe on the right may be copper, with age and corrosion, that could be an issue, too.

It isn't un-doable, but if you haven't tackled something like this before and you don't have the requisite tools, there may be some hidden gotchas!

 

[Divin Dave]

ewkearns makes a good point about having tools. I keep forgetting that not everyone is as well equipped as I am!

 

[ewkearns]

I keep forgetting that not everyone is as well equipped as I am!

 

[ricelg]

Wow! Thanks for the quick and helpful info. The part that's actually leaking is the cap to the right...the one that looks like it has more "spokes" on it. The dark gray part on top is plastic/pvc as is the white pipe.

In the Home Depot example, its just got the one top piece (brass) not 2 so I'm still not sure as to the second cap's purpose or if I can replace it independently - as that's where the leak is coming from. I don't (yet? ) have the extensive tool set yet...could be an excuse to make a purchase. But if I could replace only the grey cap to the right of the black cap, that would be much cheaper and likely much easier I bet.

Unless, of course, I'm making this much simpler than it is. If I am, then ewkearns is providing sage warning and must have seen me dive into some other projects without knowing the gotchas...

 

[Divin Dave]

Hi ricelg

if its the grey "spoke" part to the right of the black cap, its all proably still the same thing. Likely an O ring and is fixable if you have the patience (and tools) to do it. Could be also since that thing looks like its made of PVC or plastic, that there is a crack in it, in which case you must replace the whole thing.

Im not familiar with that particular one, but lots of these PVB's have springs and a "needle and seat" type of design in them. Could be a needle or ball bearing or whatever that can pop outta there when you take it apart. Things like this are part of the "gotchas".

There is also a rubber diaphram(s) or 2 in there and if you poke a hole in it, its history and the PVB wont perform the way its supposed to. So be careful.

If you can find a manufacturer and P/N on that thing somewhere, you may be able to find a rebuild kit for it online or an identical unit so you could make a 1 for 1 swap.
If you end up with a completely different design or type, then you will need to do some pipe work. Maybe add an L or 45 pr 90 deg fitting or 2, maybe get a longer nipple that is coming out of the spigot pipe or maybe a shorter one. and then some pvc stuff too.

Fact of the matter is, there's no telling, which to folks like me is part of the fun of this type stuff. Any plumbing part you will need though, is likely readily available at HD or Lowes.

For tools, looks like you'll need a couple of adjustable "crescent wrenches", or water pump pliers (aka channel locks), hacksaw, screwdrivers and such things. Maybe a smallish pipe wrench might be handy. Fun stuff!

- - - Updated - - -

No truer words were ever spoken!

 

[proavia]

The valve in the OP's post is similar to this manual irrigation valve -
3/4 in. Manual Anti-Siphon Thread Valve-L4034 - The Home Depot
I believe the black knob only controls water on/off. The right hand portion of the valve is the backflow preventor/air gap. As water pressure from the left side flows into the right side, the water flow goes vertical in an upward direction. This in turn pushes up a round disk (with a washer attached) that allows water to flow into the right side outlet pipe. In absence of positive pressure from the left side, this plunger remains in the down position. In theory, this prevents any back flow of water from the right side pipe into the left side pipe.

For the valve I referenced above, here's the rebuild kit for the back flow portion - which the OP says is leaking.
Lawn Genie 3/4 in. Shield Cap Kit-L31100 - The Home Depot

While the valve above is a Lawn Genie, yours may be from a different manufacturer. I do not know if any of the items I linked to are interchangeable with your valve. If you do decide to tackle this fix yourself, carefully attempt to remove the cap on the right side. If it's too tight, continued force could crack the cap - or worse, crack the entire valve.

 

[ricelg]

OK, thanks. I've now determined what the make/model is (Irritrol 2709PR), got the cap off, and ordered replacement parts...so I'm almost there. I'm replacing the O ring, plunger and plastic threaded cap. When I screw the cap back on, does anyone recommend using a sealant of some sort on the threads?

 

[gwegan]

I'm going to get in trouble here but whatever.

In California and in some other states (Arizona and Nevada I think) the setup above does not conform to the building code. A listed back flow preventer is required. Price one of those babies at HD!!

Anyway for the average homeowner rather than service the valve just replace it with a new one.