Plumbing - Day One

Prerequisites for Plumbing:

• Excavation completed

The plumbing sub is responsible for all the pool equipment and PVC plumbing necessary to take care of things like pool filtration, pool cleaning, chlorination systems, waterfalls, pool/spa heating, spa jets/air, skimmers, aerators, auto water-levelers, drains/returns.  This would include all the pumps, filters, gas heaters, and chlorinators.

There are tons of pool companies in AZ that offer pool deals that give you a 80ft perimeter, 400sq ft surface area, pebble interior pool that start  from $12,000.  The problem is that you have to keep your pool within those maximum specifications or else you start paying more. Typically, pool plumbers here in AZ have a standard package or base price that includes something like this:

• 1 HP Hayward Pump

• Choice of Sand, DE, or Cartridge Filtration System

• Pool Vac Cleaning System

• 15' Plumbing Run

• Auto Water Leveler

• Standard Chlorination System

I don't know anyone who can get away with a 15' plumbing run.  If a longer plumbing run is required, and in more cases than not, it will be, you'll be paying more.  Also, if you decide to get a spa, or maybe a bigger waterfall, or want to get more fancy with your water scenarios, you'll also be looking to upgrade and the price starts to climb.  This was true in my case.  Before I called in the plumber, I wanted to understand how pumps and valves work and to at least be able to sketch out in my mind how the whole thing would work.  Keep in mind, as an owner/builder, its not required that you understand all this, but it sure helps you communicate with the subs more effectively.  And effective communication with the subs is a key to getting the best possible pool you can get for your money.  I found a great site that explains the operations of pumps and valves.  Here was my final valve scheme prior to the plumber arriving (go to the pump/valve section to see how I arrived at this)

One other thing I wish I had spent more time doing but didn't, was right-sizing the pumps.  By right-sizing the pumps, I'm referring to insuring that the type and horsepower of the pump be appropriate for the pool design.  I've learned that the typical thinking is often to get the biggest and most powerful pump that can be afforded.  Not only is this unnecessary (higher monthly electricity bills), it could also potentially be harmful (pump cavitation problems).  Right-sizing pumps can be a pretty complex process.  It involves calculating the total "resistance" that the plumbing system exerts on the pumps.  This "resistance" is what is known as head.  Calculating "Total Dynamic Head," or TDH (as its commonly referred to) involves taking into account PVC pipe run lengths, diameters, and heights (distance off the ground water will be moved).  The formula to calculate TDH is complex, and few people actually do the calculation when trying to determine the right pump size.  Fortunately, there are a bunch of assumptions that can be made to simplify the calculation and still be reasonably accurate.  For more information on this you can refer to this article.  (Note: By the time I learned about all this, the pool was almost done.  I went back to see how close the plumber was to rightsizing the pumps he had specified for me and fortunately, he was not too far off.  He had specified a 1.5HP pump for the filtration system.  My calculations specified that a 1HP pump would have been sufficient.  There would be others who would argue that even a 3/4HP pump would suffice.)

Monday, August 26, 2002 - 10:03AM
The pool plumber that I selected turned out to be the sub that does plumbing for California Pools, who are what I would consider one of the best pool builders in Arizona (they have no complaints with the registrar of contractors which is an amazing statistic).  He was extremely responsive and was quick to return calls whenever I had questions.  Beyond that, other subs that I've talked to have spoken very highly of him.  They say that he's a man who knows what he's doing.  I found out that he has been in the pool plumbing business for over 20 years.

When the plumbers arrived on Monday morning, the first thing they did was explain at a high level what they were planning to do.  The crew consisted of two guys.  Victor was the crew lead and he did all the interfacing with me.  His assistant seemed to be an apprentice-in-training.  I found out later on that Victor has been doing pool plumbing for the last 5 years.  He said that he works 6 days a week, doing 1 pool a day.  I did some quick calculations and figured that he has done over 1500 pools since he started.  I was very impressed.

I should say at the onset that all the plumbing that they laid down used Schedule 40 PVC.  That's pretty standard around here.  The PVC diameter will vary in size depending on what run its for.  I'll be pointing out the various diameters used throughout the job.  In general, the higher the pressure, the longer the plumbing runs, or the more the volume (e.g. spa therapy jets or waterfall) through the pipe, the bigger the diameter will be.   With that said, on we go.

Heater Fun
The first thing Victor wanted to know was where I was going to put my equipment.  I showed him the pool drawing and said that the location drawn in the picture was just fine.  He said that the only problem was that the heater needed to be at least four (4) feet from any property line.  "What?" I asked him.  "No one told me that.  Are you sure?"  He replied that all the heaters that he's installed in the City of Chandler are placed four feet from the property line.  I said that when I got my permit approved from the City of Chandler and no one said anything.  I even drew in exactly where the heater was going to sit in the pool drawing (using standard 1/8" scale) so that there should have been no questions about its location.  I said that my permit got approved and no one made an issue of it.  He called his boss and came back and said that he verified it with him.  I asked him to hold on a minute.  I ran into the house and dialed the City of Chandler.  Fortunately, I had kept some of the business cards of some of the guys who reviewed my plan.  I eventually got a hold of one of the City Inspectors who does the actual on-site inspections.

He explained that the code states that the exhaust vent of the heater unit must be 4 feet from any property line.  The unit itself can be within the 4 foot boundary, but not the exhaust vent.  I then asked him why my permit got approved.  He explained that this was a national code and not a state one.  As such, he said the City was not going to check for stuff like that during permit applications.  He said that the GC should know all this stuff.  Ouch.  My pride got a little wounded.  At first, I began to wonder if it would make more sense for the City of Chandler to catch certain things upfront than to find them during inspection?  I mean, I had the drawn the heater into the pool design picture and things were accurate to 1/8" scale.   But I guess things in the plan are not always accurate and ultimately, its not what's on paper that counts, but what's actually built.  Things change due to unforeseen circumstances.  How things turn out aren't always the way they were originally designed on paper.   Here was yet another situation where the experience of the subcontractor saved my skin.  I was extremely grateful that they gave me an experienced crew.

So we move on.  We tried some different scenarios, and we finally found a location that would satisfy code, and at the same time, still be aesthetically pleasing.  The pictures above shows the large 400K BTU heater unit being unloaded from the truck.  Interestingly enough, the picture on the right shows where the vent is located.  It happened to be on top of the unit located about 16" off the right edge of the unit.  This 16" encroachment into the unit would definitely help in keeping the heater closer to the wall.  Ideally, it would have been put against the wall, but with the combination of the 4' restriction and the location of the vent, I had to set it back a few feet from the wall.  In the picture below, you can see the plumber measuring the distance from the wall to the vent to determine where to locate the heater slab.  He gave it a couple of extra inches margin just to be safe.

You can see from the pictures above, the distance the unit had to be situated away from the property line.  Interestingly enough, this was the side of the house I planned to run a concrete sidewalk from the front to the back.  Given the location of the heater, I eyeballed that the edge of the sidewalk would run right up against the side of the heater pad with barely an inch or two to spare.  Whew - talk about a close shave.

Auto Water-Leveler and Source
The next thing Victor wanted to know was which hose bib I was planning to use to fill up the pool with.  He was planning to tap into it to feed the Auto Water-Leveler (AWL).  For that hookup, he used 3/4" PVC.  The AWL is the device that monitors the pool's water level and automatically fills up the pool when it dips below a certain level.  A picture is shown below.

It functions similar to a toilet.  The unit is a small cylindrical tank made of concrete.  From the picture above on the right, you can see that at the normal water level (3 inches below the top of the form), the water level will be about halfway up the housing.  Inside this chamber, there's a little float similar to the ball that sits inside a toilet tank.  The float rises and falls with the water level in the pool. When the water level gets below a certain threshold, the float activates a switch, which causes the water to turn on and flow into the pool.  The water stays on until the water level in the pool goes back up to where it belongs (3 inches from the top of the bond beam).

There were two hose bibs attached to the house that the home builder installed in at the back of the house, but due to a mix-up with the builder not installing a soft-water loop, they were plumbed directly into the house plumbing.  That meant that both bibs had soft water coming from them.  I asked plumber if using soft water was Ok, and he said that you never want to use soft water for a pool.  It wreaks havoc with all the chemicals.  I told him I had no other hose bibs that had hard water except for the one in the front of the house.  He said that he could run a 3/4" PVC line to the back and hook it up that way.  I told him I was planning to tap off that same bib in the front and run PVC all the way to the back in order to install additional hard water hose bibs in the back of the house.  Either one of us could do it, but he was going to charge me an extra $100 if he did it.  After discussing it further, we realized that the gas sub was going to do some trenching from the gas meter (which is right next to the hose bib) all the way to the equipment pad, and we could just piggy back off of his trench to run PVC to the back.  That solved that problem.

Skimmer and Main Drains
Victor looked over the excavation and started to explain that one skimmer was sufficient for the size of pool I was building.  The skimmer's job is to just skim off / suck up the leaves and other debris that remain floating at the surface of the pool.  It's installed right at the water line so that at normal levels, the water is about halfway up its mouth.  The rest of the debris should fall to the bottom where the pool vac should suck it up.  He said that the skimmer/pool drains do not provide a lot of suction.  If you look at the valve schematic, the pool vac is on a Jandy Valve with the skimmer/drains.  During normal operation, the skimmer/pool drain pipes are valved (75% / 25%) so that most of the suction goes to the pool vac side.  This means that the main drains were semi-useless as far as cleaning was concerned, but that was Ok since the pool vac would get debris off the pool floor. He said that typically, the main drains are tied to the bottom of the skimmer (as you can see in the picture).  Virtually all his pools are done this way.  One side affect of this is that if you attempted to drain the pool with the filtration pump, the pump would lose prime as soon as the water level went below the skimmer.  He said that typically when you want to empty a pool, you use a submersible pump on the bottom of the pool and feed a hose out over the side of the pool.  He said that the drains were mainly used to provide enough water from the pool for filtration.  All skimmer plumbing used 2" PVC.  That includes the run from the equipment to the skimmer and from the skimmer to the main drains.

The assistant's first task was to install the skimmer.  He tied a metal rod to the top of the form so that he had something to hang the skimmer to.  You can see from the top view how he tied the skimmer to the steel rod to make it level and to keep the skimmer height exactly where it needed to be.  

Victor studied the pool for a minute then said that he would be putting five (5) returns in the pool.  The returns are the pipes that return filtered water back to the pool.  You can see from the valve schematic at the top of the page that water is "sucked" from the pool via the pool vac and/or the skimmer/main drains.  It goes through the filter, then returned to the pool evenly distributed through these five (5) return pipes.  Victor marked where the returns were going to be located by spray-painting large "R"s in various locations throughout the pool.  The middle picture also shows a "BB" which is where the basketball sleeve is going to go.  Even though the plumbers don't put in the sleeve, they like to know where sleeves are going to be located upfront so that they can take extra precautions to go around them.  One of the returns was located right inside the spa dam wall, so he drew an "R" right on the white sandbag that was sitting inside the dam wall.  

Victor explained that the returns would all be looped, so that each return would be pressurized consistently in regards to the other returns.  Most all pool builders and pool plumbers now run looped returns to give even water flow distribution.  To me it seemed silly that any plumber or pool builder would even consider non-looped returns.  The amount of PVC pipe that is saved doing so seems to amount to no more than a few extra feet of PVC in raw materials, which is just a few extra dollars. But I guess where the goal is to cut as many corners as possible, some plumbers will still do this.  What happens is that this causes the returns at the end of the run to get most of the pressure and the returns along the run to disproportionately share what's left over.  Here's a diagram of of the difference:

This causes most of the water to come out of a couple of the returns (near the ends) and much less to come out of the remaining returns. No plumber I've ever spoken to does anything *other* than looped returns.  In my opinion, they might as well make looped returns a part of the national plumbing code.  Victor added that he would be putting in two main drains that would work off one one pipe.  This is called an Anti-Vortex drain.  This dual-drain-off-of-one-pipe is done for safety.  If someone ever got their hair stuck in a drain, the full sucking force of the pump wouldn't hold them down there as the other drain would provide relief and begin sucking stronger than the first.  They do the same thing for the spa.

The Real Work Starts
The first order of business was to set down the equipment pad using those pre-formed concrete slabs.  They put the sand filter on one slab, and evenly spaced out the three pumps on the remaining two slabs, lining them up adjacent to each other.  

Next was the trenching.  Victor worked the jack hammer, breaking up the hard compacted soil while his assistant cleared the loose dirt from the path.  They precisely measured the total width of the trench needed given the PVC pipes required for all the runs and each of their individual diameters, and dug for that exact width.  They created a trench that was 6" - 8" deep.  You'll see later on how snugly all the PVC pipes fit into this trench.  They ran the trench from the equipment area over to the edge of the pool right along the edge of the house.  They then trenched a 12" wide area along the entire perimeter of the pool, right up against the outside of the bond beam form.  It was also 6" - 8" deep and would be used for the pipes that feed the looped returns, the pool vac line, the aerator, and the AWL.  Once all the trenching was done, Victor started assembling the valves near the equipment, while his assistant started with the PVC near the main drains/skimmer.  Here are some additional pictures of them working on the valves and the skimmer/main drain plumbing.

Victor's assistant created a "T" at the bottom of the pool.  All pipes used for the main drains were 2" PVC.  The ends of the "T" were capped off.  On one end, he connected a standard PVC cap, the other end, he attached what he referred to as a pressure stack.  This is a pressure gauge with a hose bib teed in.  He explained that once all the pipes have had sufficient time to dry, they pressurize all the pipes by filling it with water.  He said that for the City of Chandler, they typically pressurize it to 35-40 PSI.  They do this to check for leaks. The section of plumbing from the main drains to the skimmer is pressurized separately from the other plumbing lines.  He said that he knows of plumbers that will not bother to pressurize this run.  Instead, they do what's commonly known as a gravity test.  Instead of sealing it and putting it under pressure, they cap off the ends of the drains with standard caps and fill the opening at the other end (at the skimmer) with water and just use gravity to check for leaks.  I told him that seems like it would be difficult to find leaks that way.  Without pressure, how are you going to see any leaks?  He said that's why he pressurizes ALL of his runs.  He explained that since this section of pipe is under the shotcrete shell, its all the more important to make sure this section doesn't have leaks.  He said that for Chandler, he will typically pressurize the pipes to 40 PSI.  This provides enough of a margin to test with.  During normal pool operation, the pressure in these pipes are approximately between 15 - 20 PSI.  If it can handle 40 PSI all the way to decking, 15-20 PSI will not be a problem later.  The way they actually pressurize the pipes is to attach a garden hose to the spigot and force water into the pipes.  They quickly read the gauge and as soon as it gets to 40 PSI, they shut off the spigot to seal the water.  It takes only a few seconds to do this.  They can pressurize this section separately because they have the ability to seal off the section that runs from the bottom of the skimmer to the main drains at the bottom of the pool.  If you look at the picture of the skimmer to the right, you'll see here's a couple of screw-in plugs at the bottom of the skimmer that creates an air-tight seal for this very purpose.  Once the pressure test is done, they remove the remove the plugs and replace it with the standard skimmer bottom.  Pretty cool, huh?

Once the main-drain-to-bottom-of-skimmer work was done, the assistant started on the spa drains and the spa jets.  For the spa drains, he did the exact same anti-vortex drain safety mechanism.  For this, he didn't attach a pressure stack.  He just capped off both ends with PVC end caps.  The pipes used for this were also 2".  The pressurization of this section will be done at the equipment site, where each pump has its own pressure gauge/spigot stack.

The pressurization of all the rest of the plumbing will be done through the spigots/pressure gauges at the pumps.  You can see the spigots attached to the pumps in the picture to the right.  All the valves will be left in the open position so that water can flow to every part of the plumbing to be tested.  The reason the main pool drain has to be done separately is because there's an air gap/break at the skimmer/main drain junction.  There's not a way to make the last section a part of the full run and have it completely sealed.  It needs to be sealed separately if its to be pressure-tested.  That's why some plumbers won't even do that run.  Its too much of a hassle.  Needless to say, pressurizing the pipes is such a vital part of doing pool plumbing.  Once the concrete is poured, its too late to be fixing pipes.  A lot of the pipes are buried right into the shotcrete.  Once its set, there's not a lot you can do.  If leaks are not found during pre-shotcrete pressurization, chances are pretty good that you will not have leaks later.  Leaks will be evident pretty quickly once the pipes are under pressure.

Meanwhile, Victor was still diligently working the valves near the pump, by this time, he had finished the crux of the valve work.  Once that was done, he started to fill the sand filter with sand, and attached the salt water chlorinator electrode / cell unit.  Here's some pictures of some of the work near the equipment.

The valve work near the equipment was very impressive looking.  The pumps were arranged as follows:  the pump closest to the sand filter was the filtration pump, the pump to its right was the therapy jet booster pump, and the pump to its right was the waterfall booster pump.  The 2HP blower pump was not installed.  The plumber kept it in the box and said that when the electricians come, they will hook it up.  They left a 1-1/2" inch pipe standing near the equipment for the blower hookup later.  This pipe runs to the spa area where it "Tees" into the spa jets.  You can see in the picture below to the left how the PVC pipes running from the equipment takes up almost every inch of width along the trench.  I didn't realize how strong SCH40 PVC was until the plumbers started using the PVC as a walkway from the equipment area to the pool.

At this point, we were nearing the end of the first day.  They estimated that they would finish up sometime on noon on the second day (Tuesday).  It was about 5:30pm.  By that time they had managed to finish the skimmer/main drain section (see picture below to left), some of the waterfall plumbing (below right), all the equipment setup, including all valves, salt water chlorinator, filter, pumps, and heater, and the spa main drains as well as getting started on some of the spa jets.  Here's a couple of different shots of what was accomplished at the end of the first day.

Notice in the waterfall area, there are three PVC pipes.  The two larger, but shorter pipes (2" PVC) will feed the waterfall (shortest one feeds the spa WF and longer one feeds pool WF.  The smaller pipe that extends to the end of the waterfall pad is the beginning of the loop that will run along the perimeter of the form.  This will feed the 5 pool returns.  This return loop used 1-1/2" PVC pipe.  Tomorrow, they will finish the spa jets/blower pipes, hook up the AWL, all pool returns, waterfall suction for both pool/spa, spa return, pool vac, aerator, and the waterfall bleed return.

Beyond that, the rest of the work is all in the spa dam wall.  This would include finishing the spa jet loop, the blower pipe loop, the remaining spa jet/blower connection, and the spa waterfall suction.  The plumbers can't finish this up until the steel/rebar subs come through and form the dam wall.  Once the steel frame for the dam wall is up, the plumbers come back a third day and run their plumbing through the steel.