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Pool Valves and Plumbing Confusing?

In a pool plumbing system, there are pipes that bring water from the pool (suction pipes), and one or more pipes that take water back to the pool (return pipes). Valves are used to control the direction of water flow, to and from the pool, and in and out of equipment. In between our suction pipes and the return pipe are the pool pump and filter, and maybe a heater.

Some pool plumbing can take confusion to new heights. If your pool was built before the mid-eighties, it's probably time to modernize. The Jandy Valve revolutionized pool plumbing with its three-way valve. It allows for consolidation of two leaky, hard to turn gate valves into one simple operation. This makes it possible to reduce the number of valves and prevent pipes from going every which way.

Many pool owners find our plumbing schematics page to be very useful in laying out new plumbing designs, or simply understanding their own layout.

Mark the Pipes!

Plumbing Schematics

Once you understand the flow of the water and know the source of each pipe above the ground, at your equipment pad, label them with a permanent marker or fingernail polish. Print bold names and use arrows to indicate water flow direction.

In a pool system, the collection of pipes and valves coming out the ground in front of the pump is collectively referred to as the suction manifold (shown blue). Typically, these suction pipes are labeled SK and MD, for skimmer and main drain. If you have an attached spa, label this pipe SPA. The valves control how much flow comes from each pipe.

After the suction manifold, one pipe carries water from the pump into the filter or filter valve, and one pipe exits the filter. The water may then enter in and out of a pool heater, and perhaps past a chlorinator or purifier, on its way to the return side manifold where the water may split into POOL return and SPA jets, or maybe a water feature.

Suction Side vs. Pressure Side

Now that you understand the direction of the water flowing from the pool, through your equipment and back to the pool – here’s another concept to grasp. In front of the pump, or specifically in front of the impeller, the water is under a vacuum, and suction draws it up from the pool. Any void in the suction side pipes or valves will leak air when the pump is on. After the impeller, the water is now under pressure. Any void in the pipes or valves will leak water. Make sense?

Pool Check Valves

A pool check valve is a one-way flow valve, and is used for a variety of purposes. Installed in the pipe, it only permits water flow in one direction.

  1. For pool systems installed several feet above the pool water level
  2. To prevent backflow from a chlorinator into a heater or filter
  3. To prevent backflow of water into a spa air blower
  4. To prevent cycling of water in a loop

Pool check valves can become clogged or broken over time. Modern pool check valves have clear lids to view operation, and are serviceable and repairable. Sealed PVC check valves are only replaceable.

How to Set Pool Valves

A normal pool valve setting would have the skimmer valve(s) fully open, main drain half open and spa drain fully closed. To operate a pool cleaner or vacuum the pool, you can close other skimmers, or close the main drain, to obtain more suction through the skimmer you are using. The analogy I like to use is that if a pool pump draws 100 gpm – and there are 3 suction lines in front of the pump, then in theory, if they are all open, they are all pulling 33 gpm. Close one valve on one line, and now the other two will pull 50 gpm each. Close one of the two open valves halfway, and your lines now pull 75 and 25 gpm. Make sense?

How to Operate a Jandy Pool Valve

Jandy Pool Valve

The internal operation of a Jandy valve, or 3-way valve is not so easily understood if you’ve never seen the inside diverter, underneath the valve lid. Under the 8 screws around the lid is a diverter that pivots in the direction, shape and size of the valve handle. In other words, inside the valve, under the handle, the diverter ‘door’ or gate of the valve is the same size and curvature and position, of the curved end of the valve handle.

As you turn the handle, you are turning the diverter, or ‘door’, and in the picture shown here, with the OFF positioned at 10 o’clock, the diverter is just barely starting to close off the top port. The range of motion allows the diverter to be positioned anywhere between 6 o’clock (completely closing the bottom port), 9 o’clock (not closing either port), or 12 o’clock (completely closing the top port).

Care and Maintenance for Pipes and Valves?

If you live in the sunbelt, particularly the Southwest, aboveground pipes are painted with spray paint to protect the PVC from the harsh sun. In the snowbelt, pipes, valves and equipment are winterized or drained of water to protect from ice expansion. Pipes and valves can become clogged with debris or plugs. A Drain King is useful in removing pipe and valve obstructions.

Pool Valve Lubrication

Jandy valves and Push-Pull Valves should be lubed every year with a Teflon based lube, like Jack’s 327 lube for Jandy Valves, and Silicone based lube, like Magic Lube II for Push Pull Valve o-rings.

"Grey" Jandy valves have grease caps that can be filled with lube, or the 8 screws can be removed (and must on early "White" Jandy Valves), and the diverter face heavily lubed. "Black" Jandy Valves are "never-Lube", but if it gets sticky or hard to turn, you can use silicone or Teflon lube.

Push pull plunger o-rings are lubricated by removing the "plunger" from the valve body, sometimes forcefully done, lubing heavily and re-inserting.

Backwash Valve Leaking?

Multiport valves or push-pull valves have a port on them where backwash water exits. Filter backwash valves are used on sand and D.E. filters. If you have a leaking push-pull valve (also called a slide valve), chances are you just need to replace an o-ring on the plunger. If your multiport (usually 6 position) valve is leaking out the waste port (and possibly making a coiled blue snake of discharge hose), then you may have a need for a spider gasket replacement. First shut off the pump and try moving the valve handle slightly which may reset the gasket or flush out debris. Sometimes, you can kind of "reset" the valve by jiggling the handle. Eventually, you'll need to replace the gasket, or the entire valve (a much easier job). When replacing a spider gasket, install it flat side down, and glue it into place with small dabs of glue or silicone. When a multiport valve leaks not out the waste line, but up from around the valve handle, then this indicates a need to replace the spring and/or Teflon washer underneath the lid.

Air getting into Filter System?

Small leaks in underground suction piping can result in a loss of pressure and air being drawn in where water should flow. If your pool was built using "Black Poly" piping or flexible PVC underground, it's probable that you will experience some problems with this at some point. Rigid PVC is not a concern. Usually the air leak is not underground, but is something simple, above-ground, and easily repairable.

The pool pump is meant to operate air free. After some time, you may notice air in the basket, especially if you have a clear lid to observe such things. This can reduce filtering efficiency, allow dangerous air to build up in filter, and sometimes prevent your pump from catching prime (being able to move water). The pump will "pump" air if it can; it is the path of least resistance. So, your system needs to be almost airtight to run properly.

The problem is usually located around the pump, aboveground. Many times on the pump lid or the pump drain plugs. Sometimes air in the pump basket can be caused by something as simple as the water level being too low in the pool. Check the skimmer weir; if the weir is stuck in an up position, it can cause the skimmer to drain and take in air. Also check that the pump lid is on tight and the o-ring is lubed, and that all pump drain plugs are tight.

A good trick in locating an air leak is to shut off the motor when it's under full pumping head pressure, and look for water to spray back; out of the void where the air was entering. You have to be quick to catch this spray-back; watching closely. This void will always be before the impeller. After the impeller is what we call "the pressure side." Any leak or void there will leak water out. Any leak or void prior to the impeller (in front of the pump impeller) will draw air in when the pump is on. When you find this void, patch with epoxy putty or silicone, or replace the part if needed.

Air leaks can also be attributed to any of the valves on the suction plumbing. Old brass gate valves, in addition to being troublesome and time consuming, tend to leak after many years of use. Air could also be entering through any glue joint or threaded joint in the plumbing before the filter pump.

Another good trick is to put the plumbing under pressure, to locate the leak. Using a Drain King puts the line under pressure. Push it down into the skimmer hole, and turn on the hose to pressurize the line backwards. Remove the pump lid and use a plug at the pump entrance. This will allow pressure to build up in the line and cause water to leak out of the air leak void.

The most common problem, 90% of the time – is a loose PVC fitting into the pump. Overheating causes the PVC threads to shrink, and suck air in around the threads. In severe cases, the pump won’t even prime, or begin to pull water. Many suction side leaks such as this are repaired with pool putty, until a more permanent plumbing repair / pipe replacement can be made. The other 10% of the time, it’s usually a loose drain plug or pump lid, or older valves that need new valve stem o-rings.

Pool losing water?

If your swimming pool loses water only when the pump is on, the leak is probably on the pressure side. The leak detection process pinpoints the area under suspicion, where the appropriate repair can be made. If the pool loses water only while the pump is off, we look towards the suction side. And if it leaks all the time, well...it could be anywhere. It is important to repair leaks to prevent erosion of earth that may be supporting key areas of the pool and equipment. In addition, pool leaks can waste several hundred gallons of your filtered, heated and chemically treated water per day!

Pool Plumbing Repair

Making DIY repairs to leaking or deteriorated pool plumbing pipes is easy. All you need is a hacksaw (or you can use a power saw – reciprocating saw or a jig saw), and some fresh PVC glue and primer. For pool plumbing repairs, be sure to use deep socket pressure fittings, made of Schedule 40 PVC. Don’t use drain fittings that only glue to a depth of less than an inch, pool fittings should glue to a depth of 1-1/2”. Also avoid using Schedule 20 PVC which is too thin walled to be useful for pool plumbing. Most common pool plumbing fittings, and PVC pipe, in 1.5” or 2” diameter, can be found at local home supply stores, and most else at a plumbing supply retailer. Poolcenter also carries a selection of specialty pool plumbing fittings.

Related Product Pages:

Drain King
Jack’s 327 Lube
Magic Lube II
Pool Putty
Spider Gaskets
Plumbing Fittings
Pool Valves
Pool Valve Parts
Valve Go-Kits

Related Blog Posts:

Inground Pool Skimmer Plumbing Diagrams
Jandy Valves - Deconstructed
Multiport Filter Valve Repairs
Pool Plumbing: Jandy Valves Replacement
Swimming Pool Valve Replacements