Troubleshooters.Com and Steve Litt's Pool Resurrection Page Present

How I Repiped My Pool Equipment

Copyright (C) 2006 by Steve Litt




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I'm Steve Litt. I created the Universal Troubleshooting Process (UTP). I create and license UTP courseware, as well as teaching the UTP onsite. I've written four books on troubleshooting: Twenty Eight Tales of Troubleshooting, Troubleshooting: Tools, Tips and Techniques, Troubleshooting Techniques of the Successful Technologist, and The Manager's Guide to Technical Troubleshooting. Past professions include software development, electronic repair and corrosion protection.

I've never been a pool professional. I've had a pool only 5 years, and until autumn of 2004 it was maintained by a pool professional. So what gives me the authority to write this web page? A few weeks ago my filter pressure could not go above 5 PSI, even when the pool appeared to partially prime. I looked for obvious vacuum side leaks, and finding none, followed a friend's advice and checked out the pump's impeller. Here's what happened...

The impeller is attached to the pump's shaft, so once you remove the motor from the pump assembly, and then remove the diffuser (pictures shown later in this document) from the motor, you have direct access to the impeller. But life is never that easy...

Generation upon generation of professional and amateur pool repair personnel had made the pool's piping into a patchwork of fittings. The last guy who worked on the system repaired a leak in the drain/skimmer valve, but to do that he had to mount the pump such that the pump motor was 3/4 inch from the house, as shown in the following photo:
Pump mounted too close to house Notice the quarter wedged between the pump and the house. If you click the image to enlarge it, you can see George Washington on the quarter.

This is much too close to pull the pump motor out of the pump assembly, and as you can see, the pump assembly is solidly piped in place. I needed to totally repipe.

So I repiped. It wasn't easy, it wasn't fun, and currently there's still a very slow pressure side leak at either the pump fitting or its union. But I was able to disassemble the pump, find a clogged impeller, replace it and some worn bearing sleeves, and get the pool equipment running better than it's run in years. This document tells the story of the repiping.

The Original Configuration

Here's the original configuration:

Old piping configuration
Five pipes come from the left and are then brought above ground. These pipes, from back to front on the left underground, are:
  1. From skimmer
  2. From drain
  3. To special pool cleaner jet
  4. To spa jets
  5. To other pool jets

Actually, #4 and #5 might be reversed, because their valves are inoperable, so I can't experiment to see which is which.

The drain and skimmer pipes come up to the drain/skimmer valve, which is very close to the pump itself. There was no way to move the pump forward, because the pump is already very close to the drain/skimmer valve, with no way of reducing the piping length. To move the motor forward, I needed to move the drain/skimmer valve. I decided to move it to the left.

The New Configuration

Here's an as-built photo from the front while it's still excavated.
As built from front, still excavated
Notice that of the original pipes, only the back two were rerouted or changed. The back pipe, which is from the skimmer, was cut about a foot to the left of the former elbow, and brought straight up. The second to the back, which is from the drain, is cut about 1/2 foot to the left of its former elbow and brought straight up. Thus, no effort was made to have the T between these parallel to the house, and indeed it's not.

The new vertical pipes were aligned with a bubble level to ensure that they point straight up. They were cut off at a point indicated by a level, to ensure that each pipe stub ends at the same height. Each of these vertical pipes terminates in a union.

Attached to these two unions is a device I constructed to substitute for the old drain/skimmer valve, which costs at least $27.00 (for the cheap one) and has no screw in ends, meaning that one mistake with the pipe glue and you've blown at least $27.00. I substituted two ball valves and a T.

The output of my "freelanced drain/skimmer valve" goes to a flexible PVC pipe, which in turn goes to an elbow connected to a union that screws into the intake of my pump. A union is also screwed into the output of my pump.

The following is the a view of the output piping from the pump. Notice that I inserted a roofing shingle behind the output piping so as to obscure other pipes and make the output piping route clearer:

Piping from pump output, as built
This piping goes from the pump output to the six way valve on the filter, but I'd like to discuss it going the other direction. To really observe this, you should probably click the image for a full sized image.

A 2" threaded male to 1.5" socket female is screwed into the 6 way valve. Into the socket goes a short piece of 1.5" pipe. Onto that pipe is glued a union. A series of three 90 degree street elbows go into the other side of the union. The first two street elbows form a 180 degree turn, while the third diverts downward toward the pump.

Into the downward facing street elbow is glued a very short piece of 1.5" flexible PVC pipe, followed by a coupler, followed by a couple inches of flexible PVC, which is glued into the union that screws into the pump's outflow hole.

The intent was actually to go flexible PVC all the way from the downward facing street elbow to the union on the pump's output. That would have literally given me "wiggle room"  in case I got an angle wrong. However, when I went straight flexible, unfortunately I cut it 1/2 inche too short, which would have caused stresses that could have popped off the pipe, draining my pool, floating it, and ultimately busting the whole pool. So I added a half inch by sawing the flexible pipe and inserting a coupler.

So now, with unions on the pump's input and output, and unions at the other ends of the pump's input and output, I can disconnect and reconnect the plumbing of the pipe in minutes. The toughest part is disconnecting the electrical connection. So what I did was get a new plastic conduit that was a few feet longer than the original conduit, so I could lift the pump and put it on a work table at the side. There, I could either work on the pump with the electrical still connected (circuit breakers off, of course), or I could take off the pump motor's back, unscrew the electrical connections, remove the electrical fitting, pull the wires out of the pump, and walk off with the pump.

Here's what the finished job looked like after backfilling:
As built, backfilled
Doesn't look half bad, does it? Because most of the curved portions of the flex PVC is buried, a quick glance looks like all solid PVC. A closer look reveals that the pipe exiting the T from the ball valves on the drain and skimer pipes is flex, the pipe coming into the intake side of the pump is flex (it's the same length of flex as exits the T), and the first couple inches of pipe at the outflow is flex.

The "home brew skimmer/drain valve" is too high, but I wanted to have extra piping to cut down if I made a mistake. There's too much glue outside all the joints, but I was more concerned with solid connections than aesthetics.

Critique on My Job

Bottom line -- my job works perfectly except one small leak at the pump output union. By small I mean a matter of drops -- less than a gallon a day, probably less than a quart a day. It drips harmlessly down the pump body, onto the concrete pad, and evaporates. No big deal.

Flexible PVC pipe has some big advantages:
And it has some disadvantages Solid pipe is what professionals use. It's less likely to fail (as long as the equipment is not subjected to movement or excessive vibration), it's neater, and it give physical stability to the whole system. Solid pipe has one huge disadvantage -- it's an artform to get right. If a pipe cut is 1/4 inch wrong, it might as well be 10 feet wrong. If an elbow is set 3 degrees wrong, it might as well be 180. Even dry fitting everything before gluing is no guarantee, because elbow angles must be unchanged from the dry fitting, and because you typically cannot seat pipe into a socket as deeply dry fitting it as you can (and should) with glue.

There are people, including all plumbers and pool equipment installers, who can easily get solid pipe right the first time. I've seen them do it. But it's an artform -- they "just know" where to cut the pipe, and how to make their angles. Civilians like you and me could measure 5 times and are still likely to get it wrong while gluing.

New construction is easier. You start at one end and just fit stuff. If something's a quarter inch off at the tail of the run, you just move the sink or the pump or whatever. Retrofits are much harder -- there's no margin of error (well, maybe a 16'th of an inch.

So you do your best. Unions provide ways to join pipe and adjust angles without gluing. You connect two parallel pipes by connecting with unions and then a length of pipe with elbows such that it describes a 180, that length of pipe being such that the other end of the 180's fit smoothly on the ends of the parallel pipes, which of course have been cut to the same length using a bubble level or square ruler. An example is my "home brew" drain/skimmer valve:

Home brew drain/skimmer valve
Home Brew Skimmer/Drain valve
Using a level, I made sure the two pipes sticking out of the ground were vertical and therefore parallel. Using a level, I cut them both off at the same height. Now, if I made a precise 180 whose elbows were spaced the same distance as the pipes out of the ground, and whose vertical legs are the same length, it should all just go together.

So I carefully cut four 4" lengths to go on either ends of the ball valves (the things with the black handles), thereby guaranteeing that if I pushed all pipes into all sockets all the way, the leg lengths would be the same.

Making the elbows parallel can be done several ways. If the elbows are identical and along a straight length of pipe, as in this picture, you can twist upon gluing until all downpointing sockets lay solidly on a hard, flat surface. An easier, though not as accurate, way is to place 10 foot PVC pipes in the downward pointing sockets. Glue the other ends of the sockets, have a helper move the long pipes while you press everything together, and then your helper can lay all the pipes on the ground. Assuming you do this on a flat piece of ground, the lineup should be quite close to perfect. This is not an artform -- it's a procedure anyone can follow.

If a helper isn't available, you might be able to do it yourself by making the pipe extensions only three feet instead of 10 feet.

I used a long run of flex PVC on the vacuum side of the pump, on the theory that it's much less likely to "pop out" of a glued joint, because the vacuum would tend to pull it in rather than push it out. That long run was easy to make and easy to fit. Flex PVC is less likely to pop out on the suction side, and if it does, I burn out my motor, but don't drain, float and break the pool the way a break on the pressure side would.

Flex PVC can't take tight turns the way elbows can, meaning that the connecting flex PVC must bulge up, down, forward or back. I chose down, and then buried most of it.

My sole significant dissatisfaction is with my connection from pump to six way valve. Although it's short and looks good, leaked, and with good reason. It was imprecise, repaired, and strongarmed.

What would have been nice would have been to elbow straight up from the valve's union, and then U straight down to a pipe going to the pump's outflow union, similar to how I did the home brew drain/skimmer valve. Simple, few elbows, relatively easy to pipe even without flex. However, that would have interfered with access to the 6 way valve's handle.

An obvious but unacceptable alternative would have been to elbow horizontally out both the pump outflow union and the valve union, and then U the two. Easy, but you're not supposed to have a bend within 6 inches of the pump's outflow -- cavitation and all that.

Perhaps I could have come left out of the valve's union, then up, come up out of the pump's union, made sure they were parallel, made sure they were truncated at the same height (use a level), and then capped them with a correctly lengthed 180 bridge. It would have looked uglier, had 1 more 90 degree elbows than what I have now and the impractical solution of coming straight up out of the valve, but I could have done it with the precision necessary to make a water tight connection, and it wouldn't have interferred with operation of the valve handle, and it probably could have been done without flex. Oh well, next time.

What I Really Need to Learn

What I really need to learn is how plumbers make these connections. They don't take the whole day planning and measuring. They just visualize, measure, cut and glue. Yet they must be following a process -- otherwise they wouldn't succeed. When I learn what plumbers know that we don't, I'll report it.

Tools and Supplies for Repiping

A lot of what makes repiping easy or hard is the tools you use. This section lists some tools you'll probably need:

Digging and clearing tools
Tools for digging and clearing
Here are the required digging and clearing tools, from left to right
  • A shovel, needed to uncover buried pipes
  • A broom to sweep the pipes clean to see what's going on.
  • A lopper (the cutting device with two wooden handles and red handgrips) to cut roots and bushes.
  • A small trowell to dig delicately around pipes, scoop dirt from under pipes, and dig between closely spaced pipes.
  • A pruner (in picture, rusty blades, blue and yellow handles) to clear light weeds, especially those with thorns.
  • A wood saw to cut roots and bush trunks too large to cut with the lopper.

Needed Supplies
Here are some of the major supplies needed for a repipe project, listed from left to right:
  • Silicone Sealant: Shown with its dispenser cap to its immediate left, this is what you put on teflon tape in order to securely seal threaded connections.
  • Pool and Spa Lube: Gasket grease to ensure sealing of rubber gaskets.
  • PVC Pipe Primer: For optimally sealed glued connections on PVC pipe, the pipe surfaces must be prepared with primer before gluing.
  • PVC Cement: Glues PVC pipes together. Use the kind that can be used on wet or dry surfaces, because much of the piping you'll cement will have water inside.
  • Wire pulling lubricant:  Makes pushing wires through conduit much easier.
  • Teflon tape: Coat all male threads with three layers of teflon tape to ensure water tightness. Once the teflon tape is applied, coat with silicone sealant for maximum water tightness.

Piping tools
Piping Tools
Here are some of the tools necessary for piping, from left to right:
  • Rag: You use this to clean pipe surfaces, for cleaning dirty fingers, and other cleaning tasks. 
  • Ratchet driven PVC pipe cutter: Be sure to get one capable of cutting 2" pipe. This cuts pipe very quickly and surprisingly accurately.
  • Small PVC pipe saw: Use this to saw PVC pipe in spaces too tight for the pipe cutter.
  • Hacksaw: Use this to cut flexible PVC piping.
  • Scissors: Cut teflon tape with this.
  • Small strap wrench: Grab and twist objects of any shape, even round pipes. The thin rubber strap fits in the tightest places. Also handy for removing a stuck top from the PVC cement can.
  • Large strap wrench: Maximum torque, wide rubber strap.

About the rag. You can also use a small rag (socks work great) to stem the flow of a drain or skimmer pipe after you cut it. Gives a whole new meaning to "put a sock in it". BE SURE to remove the sock before gluing additional pipe length. A better way to stem a gravity fed flow from a drain or skimmer line is to have a 4 foot pipe with a 90 degree elbow, creating a 4 foot standpipe. Unless the swimming pool is considerably uphill from the area where the pipe is cut, the water will not rise above 4 feet.

Here's how you use the ratchet driven PVC pipe cutter. You separate the jaws by pulling the handles ALL THE WAY apart. You cut by pushing the handles together, and once they're together, separate them until the ratchet clicks, and push them together again. Continue throught the ratchet clicks until the pipe is cut. Note that the first cut should be made slowly, adjusting in order to get a right angle cut.

Electrical tools
Electrical Tools
From left to right, here are the necessary electrical tools if you need to rewire from your timer box to your pump, or just disconnect the pump from electrical wiring:
  • Voltmeter: Never trust a breaker. After turning off the breaker, measure the voltage to make sure you really have zero voltage. The pictured meter has sentimental value.
  • Lock: Once you've turned off the breaker and measured zero voltage, lock the (pool) breaker box to assure that nobody turns it back on again and curls your hair.
  • Medium flathead screwdriver: General screwing and unscrewing.
  • Small flathead screwdriver: For small screws.
  • Large flathead screwdriver: For applying big torque when necessary.
  • Electrician's pliers: Great for stripping insulated wire, and heavy duty bending and grabbing.
  • Needlenose pliers: For forming stripped wire into loops to go under screws, and to guide wires through tight spaces within the back of the pump.

Measuring tools
Measuring Tools
From left to right are the measuring tools I used for this repiping.
  • Marker pen: After measuring, mark. After dry fitting, mark angles on elbows and pipes that connect to them.
  • Short ruler: Draw straight lines, measure short distances.
  • Level: Make sure pipes are precisely horizontal or precisely vertical. Use the square to terminate parallel vertical pipes at the same height, as I did on my home brew skimmer/drain valve. You can do the same thing on horizontal parallel pipes. The pictured level is too long for a lot of work. Try either to get a shorter one, or have one short and one long one.
  • Square: This is how you make right angles. If you need to connect parallel pipes that aren't horizontal or vertical, you can't use a level, but instead must depend on this tool to make an easy U connection. Also good for measuring distances.

Pipe and Pipe Fittings

Useful couplings
Useful Pipe Fittings
These are the more useful couplings, listed from front row to back row, left to right:
  • Front row
    • Straight coupling
    • Bushing
  • Middle row
    • 45 degree elbow
    • 90 degree elbow
    • 90 degree street elbow
    • Male adapter
  • Back row
    • Union
    • Compression coupling
    • Expansion coupling

Straight coupling This has socket ends on both sides, meaning you push in the pipes and glue. It's used for joining pipes in a straight line.
Bushing You push in and glue a bushing into a larger coupler to make a smaller one, in order to reduce the size of the larger coupler. The one shown here reduces a 2" to 1.5". Useful in pools with 1.5" piping that use 2" filter piping.
45 degree elbow Sockets on both sides, this joins two pipes at a 45 degree angle. These restrict flow less than 90 degree elbows, but are trickier to route, and much less common than 90 degree elbows.
90 degree elbow This is the most common way to change the direction of piping. Sockets at both ends.
90 degree street elbow Same as a regular 90, except that one end is reduced to push into a socket. This means several street elbows can be cascaded without the need to cut piping studs. You can make a 180 with a street elbow and a normal elbow.
Male adapter This is male threaded on one end and a socket on the other. Typical use is to screw into the pump holes, and then glue a pipe to the socket end. Always use teflon tape on the threads, and always use silicone sealant over the teflon tape.
Union Used as a disconnect. Most unions are socket on both ends, although some unions sold by pool stores are male threaded on one end to screw directly into a pump. By having unions on both ends of a run of solid pipe, that run can be removed (and presumably its joined equipment moved). See my run from the pump to the six way valve as an example.

Another use is in making a U connection on two parallel pipes, like my home brew drain/skimmer valve.

One benefit of a union is that it acts as an angle microadjustment, without torquing pipes or twisting threaded connections. Everyone I've talked to likes unions.

See the Unions subsection for more detail.
Compression coupling This coupling gives you "wiggle room", in length (maybe 2 inches), rotational angle (360 degrees), and direction (maybe a couple degrees). I didn't use one because I didn't know how water and air tight they'd be, but they look promising.

See the Compression Couplings subsection for more detail.
Expansion coupling This coupling gives you about 2 inches wiggle room in length, 360 degrees in rotational angle, but none in direction. I didn't use one because I didn't know how water and air tight it would be.

See the Expansion Couplings subsection for more detail.

Straight PVC

10 foot PVC pipe
Standard Schedule 40 PVC Pipe
This is a 10 foot section of PVC pipe (schedule 40). This is how you buy schedule 40 pipe. To make longer runs, you join sections with couplings. The deformation you see near the top of the pipe is actually the store's bar code.

Flex PVC

Flexible PVC
Flex PVC pipe
This is flexible PVC piping. It's sold in some pool supply stores. I bought mine at Pinch-A-Penny. It comes in both 1.5" and 2" sizes, and in five foot lengths. As I remember it's about 2 bucks per foot, and on the Internet you can buy 50 and 100 foot rolls more economically, but it's still expensive, so use it sparingly if at all.

The reason I say "if at all" is that flex PVC is more likely than rigid PVC to fail, either coming unglued at a joint or ballooning. Not that the guidelines at say you shouldn't use it when you have a booster pump because the water hammer will eventually make glue joints fail (oops, I have a booster pump), termites can eat it (oops, I buried some of it underground). They mention that although it's dimensionally like schedule 40, it does not conform to all schedule 40 specifications. They list some other factors that aren't applicable in my case.

So why, you might ask, did I use flexible PVC at all? Because it makes it much, MUCH easier for a layman to repipe his equipment. My pool was turning a milky green -- I had to get my filtration system running. A year or two from now, when I'm a piping expert and can run rigid pipe run with 3 90's in 3 dimensions in my sleep, I can repipe with rigid. But for now, flexible PVC was easy and quick.


A union
This is a union. It has sockets (glue and slip pipe in) on either side.

A union serves as a quick connect/disconnect, and also as an infinite (360 degree) variable pipe rotation. It provides very little wiggle room for directional angle and length, but might be useful in compensating a 1/16" length discrepancy or an directional angle discrepancy of a degree or two.

A Union actually consists of three parts...
Disassembled Union
Disassembled Union
A union consists of three pieces, which in this picture we'll refer to as left, middle and right.

It's pretty obvious that the rubber gasket on the left part mates with the smooth surface on the right part to make a tight seal, and the middle part is used to screw the left and right part together. The left part has external threads mating with the internal threads on the middle part.

The right part fits within the middle part such that the external lip on the right part is caught by the internal lip on the middle part, such that when the middle part is screwed on to the left part, the middle part forces the right part against the left part.
Partially assembled Union
Partially Assembled Union
Here you see the right part inserted into the middle part. All that remains is for the middle part to be screwed onto the left part. Always hand tighten -- never tighten with a wrench. Unions are designed to be hand tightened. If you can't eliminate leaks by hand tightening, you've done something wrong -- probably a bad directional angle or a wrong length. You can sometimes lessen the tendency to leak by using pool and spa lubricant on the rubber gasket -- the same as you would for any other gasket.

There may come a time when you need to unscrew a union and cannot do it by hand. In that case, use a strap wrench, but BE SURE to turn in the direction of loosening -- not tightening. How can you tell which direction loosens? Read on...
Union: Side with a gap
Union: Side with a gap
As described previously, two of the three parts of a union have threads and screw together, while the third part has no threads and is simply pushed by the (middle) threaded part. The threads are all standard -- screw in clockwise, unscrew counterclockwise. So the only thing you need to know is which two parts are threaded.

The two pictures on the left are snapshots of a union from its two different sides. Looking carefully, you'll see that in the upper picture, there's an easily noticible gap between the serrated part closest to you and the middle part. The gap is at the serrations. That gap means that the part closest to you is not threaded. It has an external lip that is pulled in by an internal lip on the middle part. This means that the middle part and the part farthest away from you are threaded, which means that when viewed from this angle, you unscrew by turning the middle part counter clockwise. You should also grasp the part farthest from you so that such turning doesn't put a torque on the piping.

The lower picture is provided to show what a no-gap situation looks like. Here it is clear that the serrated part closest to you has no gap at the serrations. There is no gap because the serrated section is part of the male threaded part that screws into the middle part. If the view looks like the lower picture, you would grasp the part closest to you to prevent torque on the piping, and then turn the middle part clockwise, which is the equivalent of turning the part closest to you counter clockwise. Of course you can't turn the part closest to you, because it's glued to piping, so instead you turn the middle part in the opposite direction.

So, to summarize, if you see a gap, from that perspective turn the middle part counter clockwise while grasping the part farthest away from you in order to prevent torque on the pipe. If you do not see a gap, turn the middle part clockwise while grasping the part closest to you.
Union: Side without a gap
Union: Side without a gap

Compression Couplings

I haven't tried these, but they look promising, always assuming they're water tight (on the pressure side of the pump) and air tight (on the vacuum side). These couplings give three different kinds of wiggle room:

  1. Length -- you have 2 or 3 inches of play, which more than makes up for variation in coupling insertion and less than perfect sawing/cutting.
  2. Rotational -- you can adjust the relative rotation of the mating parts up to 360 degrees, in the tiniest imaginable increments.
  3. Travel direction -- although I'd assume you'd get the best seal inserting the pipe straight into the compression coupling, it looks to me like you can vary it by a few degrees (I won't guess how few, but I'd guess more than you could with a union). And unlike a union, the direction variation doesn't simply torque and bend the pipe -- the bend takes place at the rubber compressor of the compression coupling.
Another cool thing from the point of the pool piping layman is that there's no glue involved. Pipes are inserted on either end, and those pipes are snugged up by rubber gaskets compressed by the screw ends. Let me repeat that: No glue involved!

In short, although I don't know how water and air tight compression couplings are, I do know they provide quite a bit of wiggle room for the pool piping layman.
Compression coupling
Compression coupling
Here's a compression coupling. Unlike a union, it's completely symetrical. Unlike a union, it's a glueless coupling. I don't know how well it holds water and air because I didn't use one, but I can tell you it probably has the most wiggle room of any coupling discussed on this page.

Compression couplings are NOT useful as disconnects because pipes must be pulled out in order to disconnect, and that might not be possible. Unions are still your disconnect of choice.

Compression couplings are useful when you need wiggle room -- for instance, in a short run of rigid PVC where the run has several angles in multiple dimensions.

Disassembled compression coupling
Anatomy of a compression coupling
To the left you see a disassembled compression coupling. The thick rubber gaskets fit into the central body, and the pipes go through the thick rubber gaskets and into the central body. The threaded nuts on the outside screw into the threads on the central body, compressing the thick rubber gaskets until they hold tight to the pipe that goes through them.

Notice that the compression coupling is symetrical. Notice that it has a total length adjustment that's a couple inches less than the length of the central body.

The next few photos show how to assemble a connection using a compression coupling.

Beginning the assembly
Starting the assembly process
You start the assembly by making sure the compression coupling's end caps are placed around the pipes to be joined, and then push the gaskets onto the pipes approximately an inch in from where you want the pipes to come out of the compression coupling. You're now ready to screw everything together.

You now insert the pipes into the central body, until the rubber gaskets resist further pushing. There's no reason to strongarm the pipes in, because you can make fine adjustments later.

Assembled, ready for final adjustments and tightening
Ready for adjustment and final tightening
Here you see that the endcaps have been lightly tightened, but not so tight as to compress the rubber gaskets into the pipe. Now's the time for adjustments in length, rotational angle and even travel angle. This should probably be the last fitting tightened/glued in the run, because this one has the most adjustability. When it's adjusted the way you want it, strongly hand tighten each endcap.

Using Compression Couplings in various situations

The preceding sequence of photos showed the use of a compression coupling where both pipes to be connected are currently loose and free. If even one of them is loose and free, that's about the same thing. But what if both pipes are rigidly in place?

There are two situations where the pipes are rigidly in place:
  1. The compression coupling was there already
  2. The compression coupling is not yet there
In situation #1, just do your adjustments as you would in new construction. The compression coupling's already there -- no hassle.

Situation #2 is trickier, and in fact is more suited to using an expansion coupling. But if you must, you can use a compression coupling on a straight run (for instance, repairing a broken underground pipe), by following these directions:
  1. Dig out the broken pipe so as to expose a couple inches more than the length of the expansion coupling on one side of the break, and enough room for a straight socket coupling and a few inches of pipe on the other. For this example, let's say the side with room for the compression coupling is the left side, while the side with room for a straight socket coupling and a few inches of pipe is the right side. Remember, when I say "on the side of the break, I mean on the side of the cut you'd make to completely eliminate all breakage and cracks.
  2. Cut out the breakage. 
  3. If the distance between the pipe ends is less than the sum of the total length of the compression coupling (not just the central body, but the whole thing) plus the straight socket coupler, cut the right side pipe to achieve that distance.
  4. Push one end cap, then one gasket, then the central body of the compression coupling onto the left pipe. Be sure the end cap has its threads toward the pipe end.
  5. Cut a piece of pipe so that when pushed all the way into the straight socket coupling attached to the right pipe (it has not yet been attached), the new pipe section will end an endcap's width from the left pipe end. The reason for this gap is you must be able to slide an endcap between the two pipes. If the coupling is bigger or smaller than 1.5", adjust this gap accordingly. What you need is a gap just a little wider than the endcap, so the endcap can be placed between the pipes and then slid up the right side.
  6. Glue a straight socket coupling to the right pipe on one side, and the newly cut pipe stub on the other. Press and twist until fully seated on both sides of the straight socket coupling.
  7. Wait for sufficient drying so that further manipulation doesn't create a leak.
  8. Slide the remaining endcap on the right pipe, threaded side toward the pipe end. If there's not enough room to install the endcap, cut the right pipe so there is enough room.
  9. Slide the remaining gasket on the right pipe. Slide it up a couple inches.
  10. Maneuver the central body until it's centered over the gap.
  11. Move gaskets and endcaps until the entire compression coupling is centered over the gap.
  12. Tighten the endcaps and test.
If that sounds too difficult and complex, then in cases where a long, straight run has been cut and you need to patch it, follow this shorter sequence:
  1. Use an expansion coupling

Expansion Couplings

Expansion coupling
Expansion coupling, contracted
Here's an expansion coupling. As shown, the right hand side is a socket into which you glue one pipe. The left side fits into a socket.

The cool thing about an expansion coupling is it stretches, as shown in the lower photo. You install it contracted, then stretch it to fit the gap.

Expansion couplings include a union-like disconnect, so that your cut length needn't be exact. Just separate the two sides of the expansion coupling, glue a straight socket coupling on the left pipe, glue the left side of the expansion coupling into the other side of the straight socket coupling, glue the right pipe into the right side (socket) of the expansion coupling. When dry, stretch or shrink the coupling as needed to screw in the disconnect.

If the broken part of the pipe is longer than the fully stretched pipe (plus straight coupling), you can add a straight socket coupling and additional pipe to one side (the side that the expansion coupling's socket coupling goes to. If the broken part is less than the the compressed size of the expansion coupling plus the straight socket coupling, you can cut one of the pipes to give added room. The expansion coupling gives a couple inches of play, so measurement must be reasonable, but not critical.

Expansion coupling, expanded
Expansion coupling, expanded

Electrical Wire, Conduit and Fittings

Electrical fittings, contuit and wiring
Electrical wire, fittings and conduit
Loops, clockwise from left:
  • 1/2" plastic conduit
  • Black wire for hot(s)
  • Green wire for ground
Fittings inside conduit loop, left to right:
  • J shaped fitting
  • Straight fitting
  • Wire nut (I didn't use these, but list it here)

Straight electrical fitting

This is a straight electrical fitting, which joins a conduit (and the wires within it) into an electrical box in a waterproof manner. It consists of three parts.

Straight fitting, apart
Straight Fitting, Apart
Above is the straight fitting, taken apart so you can see how it works. Below is a closeup of the centerpiece, conduit side. The other side of the centerpiece is the box side.

The conduit slides over the small pipe, and under the teeth. The top piece is then screwed on the thread, clamping down on the teeth and locking the conduit in place. This makes it watertight.

On the box side is a small threaded pipe with a rubber ring, and a lock nut. The threaded pipe is screwed into the box (or pushed in if the box isn't threaded). Then the locknut is tightened from inside the box, thereby securing the fitting to the box.
Closeup of the fitting's centerpiece
Straight Fitting, Centerpiece

Electrical conduit attached to box
Conduit attached to box
Here's a picture of the electrical conduit attached to the box.

Separating the conduit from the box
Separating the conduit
In this picture, the acorn shaped top of the straight fitting has been removed, so that now the conduit can be slipped off.

Conduit separated
The conduit has been slipped off, revealing the wire.

Using an electricians pliers to remove the locknut
Using an electricians pliers to remove the locknut
Now the locknut is being removed with an electrician's pliers.

The locknut is now removed
The locknut is now removed
Here you see the locknut removed, so that the fitting can be removed from the box.

Conduit and wires removed
The wires are removed from the box
The conduit and wires are now completely removed from the box.

After having worked on this, I think there's a very specific order in which to do all of this. It's possible to attach the fitting to the pump, and then push the wires through the fitting, fasten the conduit to the fitting, and then screw down the wires. Doing so would leave little room for working with the wires.

Instead, I recommend leaving the fitting unattached to both the conduit and the pump. Strip the wires. Push the wires through the fitting and then the fitting and wires through the hole in the pump. Put the locknut around the wires, and then move the wires as closely as possible into position to be screwed down, looping the ends of the wire as necessary. With the wire ends as close as possible to their screws, NOW is the time to screw the fitting into the pump, screw in the locknut, and then fasten the conduit to the fitting. Doing it this way gives you more maneuverability in working the wire ends through the pump hole and close to their destination screws.


Repiping pool equipment isn't like putting together a bicycle or building something with lock-together blocks. There are no discrete angles on elbow joints. Socket joints have no defined depth -- it all depends how hard you push, how snuggly the pipe fits the socket, how much glue you use, and how quickly it dries. A two degree direction mistake or a quarter inch mistake in cutting or socket fitting can render an entire pipe run useless. Unlike systems that bolt together, you can't take it apart and try again -- you must buy all new.

Nor is dry fitting a guarantee. During dry fitting you can't get pipes as far into sockets. When gluing an elbow after a dry fit, you can't exactly reproduce the dry fit's angle.

There are some techniques you can use to make it easier, such as making a U connection between two known to be parallel and known to terminate at the same height or distance pipes. You can employ unions as disconnects and rotational wiggle room. You can use compression coupling to compensate for inexactness, always assuming they hold water and suction. You can use flexible PVC piping, which makes it easy, but looks ugly and is more likely to fail than rigid PVC. On the suction side of the pump, failure means a burned out motor. On the pressure side, it results in draining of the pool, and if the water table is high, pool floatation and destruction.

I'm tempted to recommend entrusting this job to a professional.

But I won't. Professionals don't take the time to set it up so future work is easy. They use nothing but rigid and glue. If you need to change out your pump, you need to cut out piping. If you need to change your pump motor, you must do it standing on your head wherever the pump basket is mounted. Professionals tend not to use unions. They take too long and cost too much.

When professionals repair pipe leaks, they go for the quick solution. Cut a pipe, put a coupling, done! Soon there's not enough pipe to patch, and repipe is necessary. Sometimes professionals pipe in such a way that the pump and pump motor are almost inaccessible -- after all, they're not the ones who will have to work on the pump motor.

I did it myself for one reason: So I could have an easy time in the future. I can have my pump ready to take to the pool store in 15 minutes. I can reinstall it in less than an hour. If my home-brew drain/skimmer valve goes bad, I can replace it for about $25 worth of parts, and probably have it all installed within a couple hours.

I originally chose to make both the runs from pump to 6 way valve, and from drain/skimmer valve to pump, out of flex ible PVC. After finding out that flexible PVC had a higher probability of failure, I decided to use flexible from drain/skimmer valve to pump, but use mostly rigid PVC from pump to 6 way valve. The theory is that pressure would be more likely to "blow out" a glue connection than suction, and if the suction side blew out, although it would burn up my pump motors, it would not drain my pool and therefore would not float or destroy it. A risk of $600.00 worth of damage is acceptable, $20,000.00 is not.

However, I did use a very short section of flexible PVC after the union at the pump's outflow hole. I did this to give myself some directional wiggle room. I needed to get the job done fast, because my pool was wasting away, turning green and chalky. I've already learned voluminously more about piping than I knew at the start of this project, and as  more knowledge is acquired over the next couple years, this piping job can be ripped out and a new one instituted. Doing so wouldn't be particularly expensive or difficult, once the knowledge is acquired.

I used six unions on this project -- two in the home brew drain/skimmer valve, one at each end of the flexible PVC pipe that runs from the home brew drain/skimmer valve to the pump, and one on each end of the run from the pump to the 6 way valve. The bottom line is that I can entirely disconnect and carry the pump away in 10 minutes, and probably reconnect it in an hour. If I buy a new pump, installing it would be an hour project if the new pump's holes were in the same place as the old one's, otherwise a few hours of minor repiping.

Yes, I sacrificed a little bit of risk for the benefit of easy installation. I'll probably redo this job in 2-4 years. But in the meantime, I got the system up and running relatively quickly, did it myself, and did it so future work on the pool will be much easier.

Sentimental Value

Pictured is my Beckman HD 110 voltmeter. HD stands for "Heavy Duty", and you better believe it's true. The company called Troubleshooters.Com began life in July 1982 as "Steve's Stereo Repair". It was begun with an ancient vacuum tube voltmeter, a five dollar card table for a service bench, and the marketing supplies, which consisted of marker pens and 3x5 cards for advertising, and a stapler to put up ad cards in grocery stores, trees, and anywhere else I could find.

By late 1982 Steve's Stereo Repair started making some money, so $175.00 was invested in a professional grade voltmeter, my Beckman HD 110. This voltmeter was used on my service bench, and also traveled to various clients, including one client where I repaired and maintained a fleet of about 20 Wollensak 2770AV cassette duplicators. I usually put all my tools on the back of my bicycle and rode to the work site. This was before bicycles had suspensions, so you better believe that voltmeter took plenty of shock.

Steve's Stereo Repair morphed into Steve Litt Business Systems in 1986, but I kept the voltmeter, and have used it ever since. It still works perfectly, and still takes a beating.

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