Plumbing Valving

Plumbing Valving

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). Pool 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 is 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.

Labeling Your Pipes

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 connected to the pipes allow you to control how much water flow comes from each pipe. Closing or partially closing a suction line will increase the water flow through the other lines, generally speaking.

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 (shown red) where the water may split into POOL return and SPA jets, or maybe a water feature. Like the suction valves, closing or partially closing a valve on one return pipe, increases the water flow to other pool return inlets.

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. The water FROM the pool is under a vacuum suction, being PULLED from the pool. After the water passes thru the eye of the pump impeller, it is under pressure and is being PUSHED through the filter and back to the pool. 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 to flow in one direction only.

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, e.g. solar heater systems

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 suction pool cleaner or manually 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 about 33 gpm or 1/3 of the total volume. Close one valve on one line, and now the other two will pull 50 gpm each. For a 2-line MD/SK set-up, turn the handle to close main drain pipe halfway, and your lines now pull at 75 and 25 gpm. Make sense?

How to Operate a Jandy Pool Valve

The internal operation of a Jandy valve, or other 3-way valves like the CMP Valve or the Pentair Valve is not so easily understood if you have never seen the inside diverter, underneath the valve lid. Under the 8 screws around the lid is a diverter that pivots in the direction 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’ which can be in a position between the two pipes, splitting the flow equally among both incoming pipes, or the valve can be turned within a range of 180 degrees, to restrict or close off, one of the two incoming pipes. Make sense?

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. Jandy type valves are serviceable, to allow you to open them up to inspect the diverter, clear out clogs, or replace diverter o-rings, which can cause leaking from the handle.

Pool Valve Lubrication

Jandy Valves and Push-Pull Valves should be lubed every year with a Teflon based lube, like Jack’s 327 lube. "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. Multiport valves do not require lubrication. Ball valves or union valves also do not require any lubrication, with exception to a union o-ring seal.

Backwash Valve Leaking?

Multiport valves or push-pull valves have a port 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 the plunger o-rings. 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 replacement spider gasket.

First, shut off the pump and try pushing down and moving the valve handle slightly which may reset the gasket or flush out debris. Eventually however, you will need to replace the gasket, or you can replace the entire multiport valve. When replacing a spider gasket, install it flat side down, and glue it into place with small dabs of super glue or silicone. When a multiport valve leaks not out of the waste line, but up from around the valve handle, then this indicates a need to replace the stem o-rings underneath the lid, and possibly also the spring and large washers.

For a complete multiport rebuild, you can replace what’s called the Key Assembly, which is everything that comes out in your hand when you remove all of the cover screws and lift the Key assy out by the handle. This includes the Handle, Cover and Rotor, all assembled with associated parts.

Air getting into Filter System?

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 and start pumping water. The pump will "pump" air if it can; it is the path of least resistance. Therefore, your pump and incoming pipe and valves need to be almost airtight to run properly.

An air leak problem is usually located around the pump, aboveground. Many times, it is a loose 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, or a skimmer weir stuck in an up position, causing 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.

The most common cause of an air leak, 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 will not 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. A CPVC nipple or CPVC union can withstand more heat than regular PVC fittings. The other 10% of the time? Usually a loose drain plug or pump lid, or older suction side valves that need new valve stem o-rings or cover o-rings.

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 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 when the pump is running. 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, replace the gasket, or replumb the fitting.

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 or put the multiport on the Closed position. This will allow pressure to build up in the line and cause water to leak out of the air leak void.

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, 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! See our Leak Detection Page for products to help you locate and repair pool leaks.

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, adapters, unions and couplers.

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