Difference between revisions of "Equipment Pad Best Practices" - Further Reading

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[[Category:Swimming Pool Equipment]]
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=What are the Best Practices for a Pool Equipment Pad?​=
  
=What are the Best Practices for a Pool Equipment Pad?=
+
If you are building your pool there are many best practices to discuss with your builder and contractor.<ref>https://www.troublefreepool.com/threads/design-your-dream-pool-pad.184681/</ref> One of them is the Pool Equipment Pad which will house your pumps, filter, pool heater, and related equipment. Before using the tips below, always check your local code and safety requirements or restrictions.
If you are building your pool here are things to discuss with your builder and contractor.<ref>https://www.troublefreepool.com/threads/design-your-dream-pool-pad.184681/</ref>
 
  
 
==Location and Layout==
 
==Location and Layout==
*Consider location carefully. Many Pool Builders will put the equipment where it is convenient for them. Have it put where you will be able to access it easily and quickly if needed
+
[[File:Equipment Pad Complex.jpg|thumb]]
*Size - 5’ x 10-12’+
+
Consider the location carefully so that it is both easily and quickly accessible. Many Pool Builders will put the equipment where it is convenient for them. Have it put where you will be able to access it easily and quickly if needed.  The equipment pad should be a reasonable distance from the pool so that you can move between the pool and equipment without a long hike.
*Pumps on one side, filter in the middle and heater on the other side.
+
 
*No pipes coming up through concrete, bring them up through crushed stone. This will help with repairs in the future.
+
Most pads require a minimum of a 4’x4’ area and depending on the equipment it could be up to a 5’x10-12’ area or larger. A pool pad can be too small to easily work with the equipment after it is installed, while the pad is rarely too large.  You will be the one working around the pool equipment on the equipment pad, not the Pool Builder or plumber, so make sure you have adequate space.
*All valves & pipes labeled for function and flow direction as well as taking a picture and printing it out in case the labels fail.
+
 
*Room to move around- you should be able put your feet between the equipment as well as be get behind all equipment  
+
A typical equipment pad layout is pumps on one side, filter in the middle, heater on the other side and pipes from the pool coming up from gravel along the side of the equipment pad. There should be enough spacing between and around equipment for regular service and repairs including access at the rear of the pumps. Room to move around means you should be able put your feet between the equipment and pipes and behind all equipment.
*Control panels on something solid like a structure wall or a wall created by posts and 2 x 10’s.
+
 
 +
The plumber should place the equipment for the least amount of turns in the pipes as possible. That is an art into itself and some plumbers are better at equipment layout and pipe runs then others.  A good plumber will leave extra pipe and straight runs between joints allowing space for cuts in the PVC to be made for repairs or additional equipment.  The pipes coming out of the ground next to the equipment pad should have at least 6”, if not more, of pipe above ground before a 90 degree fitting or valve is glued onto it.  Some plumbers will cut those pipes close to the ground leaving little extra pipe for when the valve needs to be replaced or the plumbing changed.
 +
 
 +
The equipment pad should be raised at least slightly from the surrounding ground for water drainage. Your property’s storm run-off and surrounding ground conditions are of particular importance in choosing the location. Additionally, a solid structure, such as an existing wall or new wall created by posts and 2 x 10’s, will be necessary for mounting control panels.
 +
 
 +
A side note on working with contractors — some will take direction well on what the customer wants, while others will bristle and tell you about all their years in the business and they know how to do things. Few contractors like their customer trying to tell them how to do their job. It is best to ask probing questions to discover what you should expect. And then keep a watchful eye on the work and see if it is meeting your expectations. PVC is cheap and changes can be made easily if they are immediately brought to the contractors attention. Providing water, coffee, doughnuts, or pizza goes a long way to getting contractors to put extra effort into your project.  Make your project a place the contractors enjoy working at.
 +
 
 +
==Equipment Pad Surface==
 +
The equipment pad should be of poured concrete and not simply some composite pads layed on the ground. No pipes should come up through or be under the concrete pad. Instead, bring pipes up through crushed stone on the side of the concrete pad to allow easy access for repairs in the future.
 +
 
 +
[[File:Equipment Pad Concrete.jpg|thumb]]
 +
 
 +
==Anchoring Equipment==
 +
 
 +
In Florida, some equipment is required to be anchored.<ref>https://www.troublefreepool.com/threads/intelliflo-pump-is-not-powering-on-after-power-surge.263540/post-2307258</ref>
 +
 
 +
The rules are not super clear on what is supposed to be bolted down and what it not required to be bolted down.
 +
 
 +
Anchoring can help prevent theft, vibration and wind damage.
 +
 
 +
Using a sheet of rubber below the pump before anchoring can help reduce vibration.
 +
 
 +
The Pentair MasterTemp Installation Manual says "In Florida, building codes require that the heater be anchored to the equipment pad or platform to withstand high wind pressures created during hurricanes. A Bolt Down Bracket Kit, P/N 460738, is available with anchor clamps designed to hold the unit to the equipment pad in high wind conditions. Installation of the anchor clamps are recommended in all installations and are required in Florida, (See Florida Building Code 301.13)".
 +
 
 +
"301.12 Wind resistance. Mechanical equipment, appliances and supports that are exposed to wind shall be designed and installed to resist the wind pressures on the equipment and the supports (FL’s) as determined in accordance with the Florida Building Code, Building".
 +
 
 +
==Ventilation and Sun Protection==
 +
 
 +
Good airflow is important to your pool equipment’s lifespan and proper operation. Heaters need a high volume of air intake to operate properly and you need to consider where the hot heater exhaust will blow if you have a gas heater.
 +
 
 +
Pool equipment and pipes need to be protected from the sun, especially in areas of intense sun like the Southwest USA. The suns UV rays reduce the impact resistance of PVC pipes over time.<ref>http://www.nacopvc.com/c/tech-info/the-effects-of-sunlight-exposure-on-pvc-pipe</ref> UV also causes a brown discoloration on PVC pipes. At a minimum the PVC pipes should be protected from the sun's UV rays by spray painting the pipes.
 +
 
 +
If you have decided to have an enclosed pool pad you could use a 3’-4’ fence with a small roof. Special considerations need to be given when enclosing a pool heater both for sufficient air intake and for the exhaust of a gas heater. 
 +
 
 +
While not necessary, it is common for a small, short fence or shrubs or plantings to be built on two or three sides to conceal equipment and act as a slight noise barrier for the pool pump.
  
==Ventilation and Sun Protection ==
 
*Good airflow
 
*Consider where heater exhaust will blow to
 
*Protection from sun or at least spray paint pipes
 
 
==Electrical==
 
==Electrical==
*Light overhead for night work
+
 
*120V GFCI receptacle  
+
===Pool Pad Outlet===
==Water==
+
 
*Water spigot
+
At least one 120V GFCI receptacle near the pool equipment pad is among modern best practices.  Many automation panels have a space for a 120V GFCI receptacle in their Load Center.
*Drain area or to sewer for waste
+
 
 +
===Pool Pad Floodlight===
 +
In addition, a switched overhead LED floodlight will allow you to check equipment at night.  The overhead equipment pad light can be turned on and off through an automation panel if you have one.
 +
 
 +
===Use Grey Electrical Conduit===
 +
Electrical lines for the pool lights from the pool to light junction boxes or to the equipment pad must be run in grey electrical schedule 40 PVC pipe which is different then white water schedule 40 PVC pipe.
 +
 
 +
[https://flylib.com/books/en/2.419.1/article_352_rigid_nonmetallic_conduit_type_rnc.html NEC Article 352]. The Rigid Non-metallic Conduit, elbows and associated fittings must be listed.
 +
 
 +
===No More Then 360 Degrees of Bends===
 +
Water pipe 90's should never be used on electrical PVC conduit as they are way too tight of a bend for pulling wire. Instead grey schedule 40 PVC electrical sweeps which have a much larger radius should be used. Or as an alternate, 1" PVC conduit can be bent by heating. There are heat boxes made for this purpose.
 +
 
 +
No more than a total of 360 degrees before a junction box/ hand hole is allowed by the NEC. [https://flylib.com/books/en/2.419.1/article_358_electrical_metallic_tubing_type_emt.html NEC 358.26] - Bends — Number in One Run. “There shall not be more than the equivalent of four quarter bends (360 degrees total) between pull points, for example, conduit bodies and boxes.”<ref>https://www.troublefreepool.com/threads/pool-light-electrical-conduit.258502/post-2259488</ref>
 +
 
 +
For conduits with an internal diameter of 2 inches or less, the inside radius of a bend in conduit shall be at least 6 times the internal diameter.<ref>https://www.troublefreepool.com/threads/pool-light-electrical-conduit.258502/post-2259509</ref>
 +
 
 +
The portion of the electrical conduit in the ground and/or below the top of the coping must be water tight.
 +
 
 +
===Load Center Electrical Shutoff===
 +
Install a single 60 to 120 AMP breaker in an enclosure beside the Load Center. This will save many trips to the main house panel to disconnect the Load Center before you touch any high voltage wiring.
 +
 
 +
==Water Around the Equipment Pad==
 +
 
 +
A water spigot connected to house water should be convenient to the equipment pad for cleaning your filter and priming the pump.
 +
 
 +
Working around pool equipment can be a wet process. Identify where water will drain to when you need to clean the filter. Should any of the pool equipment spring a leak where will the water run to until you discover it and can turn the equipment off?
 +
 
 +
If you have a DE Filter or Sand Filter it will need to backwashed occasionally. Backwashing runs pool water through the filter medium to remove the dirt and drains the dirty water out a waste line.  Determine where the waste line will dispose of the effluent and if your local codes allow the backwash line to be connected to your sewer line.
 +
 
 +
If you do not have an overflow drain in the pool you will need a convenient way to drain some pool water after storms or sustained rainy times. This maybe from a waste line into a sewer drain if your local codes allow or a spigot through a hose. Consider where the water will run to as it can be hundreds of gallons.
 +
 
 
==Plumbing==
 
==Plumbing==
*Valves-make sure they are the rebuildable ones-Jandy and Pentair make some good ones. Do NOT allow "ball valves" from the big box stores.
 
*Unions-make sure they use these on all of the equipment so you can service it without having to cut the pipe
 
  
.
+
For a deeper dive into pool plumbing design read [https://www.troublefreepool.com/threads/hydraulics-101-have-you-lost-your-head.830/ Hydraulics 101 - Have you lost your head?].
 +
 
 +
===Pressure Testing the Pipes===
 +
 
 +
Take all the pipes after being laid in the trench and join them together to make a pressure test configuration with the pool side fittings plugged. Pressure test the plumbing for 24hrs minimum then backfill under pressure. The pipes move when back-filling.  Leave the pressure test rig on for a few days and water the trenches to help settle and hand tamp them as you fill if narrow. After all that cut them and do the pad plumbing using diverter valves.<ref>https://www.troublefreepool.com/threads/just-completed-rough-in-for-new-pool.202965/post-1791423</ref>
 +
 
 +
===Pipe Size and Flow Rates===
 +
 
 +
You want to keep the water velocity below 6 ft/sec on the suction and below 8 ft/sec on the pressure side of the pump.<ref>https://www.troublefreepool.com/threads/does-my-pool-need-larger-pipe.220634/post-1931545</ref>
 +
 
 +
{| class="wikitable"
 +
|-
 +
! Pipe Size !! 6 ft/sec !! 8 ft/sec
 +
|-
 +
| 1.5" || 38 GPM || 51 GPM
 +
|-
 +
| 2" || 63 GPM || 84 GPM
 +
|-
 +
| 2.5 || 90 GPM || 119 GPM
 +
|-
 +
|  3.0" || 138 GPM || 184 GPM
 +
|-
 +
|  4.0" || 235 GPM || 312 GPM
 +
|}
 +
 
 +
Here is the head loss in feet for 100 feet of PVC pipe at different flow rates for 2” and 2.5” pipe.<ref>https://www.troublefreepool.com/threads/experimenting-with-pipe-sizing-length-and-flows-considerations-for-new-construction.222204/post-1946824</ref>
 +
 
 +
{| class="wikitable"
 +
|-
 +
! GPM !! 2” !! 2.5”
 +
|-
 +
|30||1.6 ft||0.7 ft
 +
|-
 +
|40||2.8 ft||1.2 ft
 +
|-
 +
|50||4.2 ft||1.8 ft
 +
|-
 +
|60||6.0 ft||2.5 ft
 +
|-
 +
|70||7.9 ft||3.3 ft
 +
|-
 +
|80||10.2 ft||4.3 ft
 +
|-
 +
|90||12.6 ft||5.3 ft.
 +
|}
 +
 
 +
As you can see, the head loss difference at 30 gpm is only about 0.9 feet, which is not very significant.
 +
 
 +
Even at 60 gpm, the head loss difference is only 3.5 feet per 100 feet of pipe.
 +
 
 +
As long as you follow the 6 feet per second rule for suction and 8 feet per second for returns, the advantage of upsizing the pipe is negligible for pipe runs less than 100 feet in length.
 +
 
 +
For pipe runs that are over 100 feet, you would want to calculate the head loss and size the pipe accordingly. Most people think that they need a bigger pump if the filter is far away. However, the pump size is the same regardless of how far away the pool is from the filter system. What matters is the plumbing size. The pump can be 1 foot or 1,000 feet away and the pump size will be the exact same. You only change the pipe size and especially on the suction since it can cavitate.
 +
 
 +
If you want to be conservative, you can use the 6 feet per second rule for the return side as well.
 +
 
 +
Skimmers should typically be designed to handle less than 50 GPM, so a 2.5" line will be about 7.2 feet of head at 50 gpm for 400 feet.
 +
 
 +
If you have 2 skimmers, you can get up to 100 gpm if you have a separate 2.5" line from each skimmer to the pump.
 +
 
 +
Returns are typically looped around the pool. if it cannot be achieved then the plumber will run a minimum of 18” of dead run past the last Tee to achieve back pressure.
 +
 
 +
[https://www.engineeringtoolbox.com/pvc-pipes-friction-loss-d_802.html PVC Pipes - Friction Loss and Flow Velocities Schedule 40]
 +
 
 +
[https://www.troublefreepool.com/threads/head-loss-specs-for-pentair-multiport-valves.204793/ Head-Loss Specs for Pentair Multiport Valves]
 +
 
 +
[[File:Head Loss vs Filter Type.png|thumb]]
 +
 
 +
===Spa Jet Design===
 +
 
 +
The first step in designing a spa is to settle on the number of jets, size of jet and how strong you would like the jet to feel. Once this is determined, the following table can be used to determine the proper pipe size and the resulting operating point for the pump.<ref>https://www.troublefreepool.com/threads/hydraulics-101-have-you-lost-your-head.830/</ref>
 +
 
 +
[[File:Spa Jet Design.png|thumb]]
 +
 
 +
The following example will help understand how to use the sizing table:
 +
 
 +
*Jet Design: 6 x 3/8" Jets @ 15 GPM/Jet
 +
*Total Flow Rate = 90 GPM
 +
*Minimum Recommended Pipe Size = 3.0"
 +
*Head Loss ~ 37' (assumes 100' of pipe and typical fittings for a spa)
 +
*Desired Pump Operating Point = 90 GPM @ 37' of head
 +
 
 +
[https://www.youtube.com/watch?v=2PjV8YR-eHE&t=519s Learn Pool Plumbing with Test Tank] is a YouTube video from [https://www.youtube.com/@jmaxplumbing JMax Swimming Pool Plumbing] that demonstrates how spa jets with an air venturi work. It also gives a great demonstration of pool hydraulics and what head is.
 +
 
 +
[https://buildahottub.com/the-ultimate-guide-to-gunite-jet-body-installation/ The Ultimate Guide to Gunite Jet Body Installation] explains how gunite jet bodies are installed and jets assembled.
 +
 
 +
===Spa Dual Pump Plumbing===
 +
 
 +
When a spa has many jets a dedicated spa jet pump maybe needed to give adequate flow without the restrictions of a filter or heater. Below is typical plumbing for spas serviced by dual pumps.
 +
 
 +
One pump provides filtered and heated water to one or two spa returns. The other pump flows directly to the spa jets. Each pump has dedicated suction ports in the spa floor.
 +
 
 +
[[File:Spa Dual Pump Plumbing.png|thumb]]
 +
 
 +
===2 Inch PVC for the Equipment===
 +
 
 +
If you have 2" fittings at the pump amd filter use 2" PVC for the equipment.  Then make your return manifold out of 2" and then use 1.5X2" diverter valves as reducers to 1 1/2" return pipes.
 +
 
 +
===Valves===
 +
 
 +
Use re-buildable diverter valves such as from Jandy, Pentair, Hayward, or CMP . The "ball valves" found in big box stores are not recommended as they are problematic, stick over time, handles can break, and are difficult to repair.
 +
 
 +
===Unions===
 +
All of the equipment should be connected with unions for cost savings over time, and for repairs to occur without cutting the pipes. The extra cost up front will prove useful the first time a repair is needed.
 +
 
 +
For Pentair pumps look for "2 PACK -CMP Hi-Temp Union 2" inch 2MIP x 2" inch PVC Whisperflo & Intelliflo - 2 PACK"<ref>https://www.amazon.com/PACK-Hi-Temp-Union-Whisperflo-Intelliflo/dp/B00AKMV4K8/ref=sr_1_1</ref>
 +
 
 +
===Labeling of all Pipes and Valves===
 +
Additionally, all valves and pipes should be labeled for function and flow direction, with permanent labels or light engraving. For good measure take a picture and print it out in case the labels fade or fall off.

Latest revision as of 20:05, 2 April 2024

What are the Best Practices for a Pool Equipment Pad?​

If you are building your pool there are many best practices to discuss with your builder and contractor.[1] One of them is the Pool Equipment Pad which will house your pumps, filter, pool heater, and related equipment. Before using the tips below, always check your local code and safety requirements or restrictions.

Location and Layout

Equipment Pad Complex.jpg

Consider the location carefully so that it is both easily and quickly accessible. Many Pool Builders will put the equipment where it is convenient for them. Have it put where you will be able to access it easily and quickly if needed. The equipment pad should be a reasonable distance from the pool so that you can move between the pool and equipment without a long hike.

Most pads require a minimum of a 4’x4’ area and depending on the equipment it could be up to a 5’x10-12’ area or larger. A pool pad can be too small to easily work with the equipment after it is installed, while the pad is rarely too large. You will be the one working around the pool equipment on the equipment pad, not the Pool Builder or plumber, so make sure you have adequate space.

A typical equipment pad layout is pumps on one side, filter in the middle, heater on the other side and pipes from the pool coming up from gravel along the side of the equipment pad. There should be enough spacing between and around equipment for regular service and repairs including access at the rear of the pumps. Room to move around means you should be able put your feet between the equipment and pipes and behind all equipment.

The plumber should place the equipment for the least amount of turns in the pipes as possible. That is an art into itself and some plumbers are better at equipment layout and pipe runs then others. A good plumber will leave extra pipe and straight runs between joints allowing space for cuts in the PVC to be made for repairs or additional equipment. The pipes coming out of the ground next to the equipment pad should have at least 6”, if not more, of pipe above ground before a 90 degree fitting or valve is glued onto it. Some plumbers will cut those pipes close to the ground leaving little extra pipe for when the valve needs to be replaced or the plumbing changed.

The equipment pad should be raised at least slightly from the surrounding ground for water drainage. Your property’s storm run-off and surrounding ground conditions are of particular importance in choosing the location. Additionally, a solid structure, such as an existing wall or new wall created by posts and 2 x 10’s, will be necessary for mounting control panels.

A side note on working with contractors — some will take direction well on what the customer wants, while others will bristle and tell you about all their years in the business and they know how to do things. Few contractors like their customer trying to tell them how to do their job. It is best to ask probing questions to discover what you should expect. And then keep a watchful eye on the work and see if it is meeting your expectations. PVC is cheap and changes can be made easily if they are immediately brought to the contractors attention. Providing water, coffee, doughnuts, or pizza goes a long way to getting contractors to put extra effort into your project. Make your project a place the contractors enjoy working at.

Equipment Pad Surface

The equipment pad should be of poured concrete and not simply some composite pads layed on the ground. No pipes should come up through or be under the concrete pad. Instead, bring pipes up through crushed stone on the side of the concrete pad to allow easy access for repairs in the future.

Equipment Pad Concrete.jpg

Anchoring Equipment

In Florida, some equipment is required to be anchored.[2]

The rules are not super clear on what is supposed to be bolted down and what it not required to be bolted down.

Anchoring can help prevent theft, vibration and wind damage.

Using a sheet of rubber below the pump before anchoring can help reduce vibration.

The Pentair MasterTemp Installation Manual says "In Florida, building codes require that the heater be anchored to the equipment pad or platform to withstand high wind pressures created during hurricanes. A Bolt Down Bracket Kit, P/N 460738, is available with anchor clamps designed to hold the unit to the equipment pad in high wind conditions. Installation of the anchor clamps are recommended in all installations and are required in Florida, (See Florida Building Code 301.13)".

"301.12 Wind resistance. Mechanical equipment, appliances and supports that are exposed to wind shall be designed and installed to resist the wind pressures on the equipment and the supports (FL’s) as determined in accordance with the Florida Building Code, Building".

Ventilation and Sun Protection

Good airflow is important to your pool equipment’s lifespan and proper operation. Heaters need a high volume of air intake to operate properly and you need to consider where the hot heater exhaust will blow if you have a gas heater.

Pool equipment and pipes need to be protected from the sun, especially in areas of intense sun like the Southwest USA. The suns UV rays reduce the impact resistance of PVC pipes over time.[3] UV also causes a brown discoloration on PVC pipes. At a minimum the PVC pipes should be protected from the sun's UV rays by spray painting the pipes.

If you have decided to have an enclosed pool pad you could use a 3’-4’ fence with a small roof. Special considerations need to be given when enclosing a pool heater both for sufficient air intake and for the exhaust of a gas heater.

While not necessary, it is common for a small, short fence or shrubs or plantings to be built on two or three sides to conceal equipment and act as a slight noise barrier for the pool pump.

Electrical

Pool Pad Outlet

At least one 120V GFCI receptacle near the pool equipment pad is among modern best practices. Many automation panels have a space for a 120V GFCI receptacle in their Load Center.

Pool Pad Floodlight

In addition, a switched overhead LED floodlight will allow you to check equipment at night. The overhead equipment pad light can be turned on and off through an automation panel if you have one.

Use Grey Electrical Conduit

Electrical lines for the pool lights from the pool to light junction boxes or to the equipment pad must be run in grey electrical schedule 40 PVC pipe which is different then white water schedule 40 PVC pipe.

NEC Article 352. The Rigid Non-metallic Conduit, elbows and associated fittings must be listed.

No More Then 360 Degrees of Bends

Water pipe 90's should never be used on electrical PVC conduit as they are way too tight of a bend for pulling wire. Instead grey schedule 40 PVC electrical sweeps which have a much larger radius should be used. Or as an alternate, 1" PVC conduit can be bent by heating. There are heat boxes made for this purpose.

No more than a total of 360 degrees before a junction box/ hand hole is allowed by the NEC. NEC 358.26 - Bends — Number in One Run. “There shall not be more than the equivalent of four quarter bends (360 degrees total) between pull points, for example, conduit bodies and boxes.”[4]

For conduits with an internal diameter of 2 inches or less, the inside radius of a bend in conduit shall be at least 6 times the internal diameter.[5]

The portion of the electrical conduit in the ground and/or below the top of the coping must be water tight.

Load Center Electrical Shutoff

Install a single 60 to 120 AMP breaker in an enclosure beside the Load Center. This will save many trips to the main house panel to disconnect the Load Center before you touch any high voltage wiring.

Water Around the Equipment Pad

A water spigot connected to house water should be convenient to the equipment pad for cleaning your filter and priming the pump.

Working around pool equipment can be a wet process. Identify where water will drain to when you need to clean the filter. Should any of the pool equipment spring a leak where will the water run to until you discover it and can turn the equipment off?

If you have a DE Filter or Sand Filter it will need to backwashed occasionally. Backwashing runs pool water through the filter medium to remove the dirt and drains the dirty water out a waste line. Determine where the waste line will dispose of the effluent and if your local codes allow the backwash line to be connected to your sewer line.

If you do not have an overflow drain in the pool you will need a convenient way to drain some pool water after storms or sustained rainy times. This maybe from a waste line into a sewer drain if your local codes allow or a spigot through a hose. Consider where the water will run to as it can be hundreds of gallons.

Plumbing

For a deeper dive into pool plumbing design read Hydraulics 101 - Have you lost your head?.

Pressure Testing the Pipes

Take all the pipes after being laid in the trench and join them together to make a pressure test configuration with the pool side fittings plugged. Pressure test the plumbing for 24hrs minimum then backfill under pressure. The pipes move when back-filling. Leave the pressure test rig on for a few days and water the trenches to help settle and hand tamp them as you fill if narrow. After all that cut them and do the pad plumbing using diverter valves.[6]

Pipe Size and Flow Rates

You want to keep the water velocity below 6 ft/sec on the suction and below 8 ft/sec on the pressure side of the pump.[7]

Pipe Size 6 ft/sec 8 ft/sec
1.5" 38 GPM 51 GPM
2" 63 GPM 84 GPM
2.5 90 GPM 119 GPM
3.0" 138 GPM 184 GPM
4.0" 235 GPM 312 GPM

Here is the head loss in feet for 100 feet of PVC pipe at different flow rates for 2” and 2.5” pipe.[8]

GPM 2” 2.5”
30 1.6 ft 0.7 ft
40 2.8 ft 1.2 ft
50 4.2 ft 1.8 ft
60 6.0 ft 2.5 ft
70 7.9 ft 3.3 ft
80 10.2 ft 4.3 ft
90 12.6 ft 5.3 ft.

As you can see, the head loss difference at 30 gpm is only about 0.9 feet, which is not very significant.

Even at 60 gpm, the head loss difference is only 3.5 feet per 100 feet of pipe.

As long as you follow the 6 feet per second rule for suction and 8 feet per second for returns, the advantage of upsizing the pipe is negligible for pipe runs less than 100 feet in length.

For pipe runs that are over 100 feet, you would want to calculate the head loss and size the pipe accordingly. Most people think that they need a bigger pump if the filter is far away. However, the pump size is the same regardless of how far away the pool is from the filter system. What matters is the plumbing size. The pump can be 1 foot or 1,000 feet away and the pump size will be the exact same. You only change the pipe size and especially on the suction since it can cavitate.

If you want to be conservative, you can use the 6 feet per second rule for the return side as well.

Skimmers should typically be designed to handle less than 50 GPM, so a 2.5" line will be about 7.2 feet of head at 50 gpm for 400 feet.

If you have 2 skimmers, you can get up to 100 gpm if you have a separate 2.5" line from each skimmer to the pump.

Returns are typically looped around the pool. if it cannot be achieved then the plumber will run a minimum of 18” of dead run past the last Tee to achieve back pressure.

PVC Pipes - Friction Loss and Flow Velocities Schedule 40

Head-Loss Specs for Pentair Multiport Valves

Head Loss vs Filter Type.png

Spa Jet Design

The first step in designing a spa is to settle on the number of jets, size of jet and how strong you would like the jet to feel. Once this is determined, the following table can be used to determine the proper pipe size and the resulting operating point for the pump.[9]

Spa Jet Design.png

The following example will help understand how to use the sizing table:

  • Jet Design: 6 x 3/8" Jets @ 15 GPM/Jet
  • Total Flow Rate = 90 GPM
  • Minimum Recommended Pipe Size = 3.0"
  • Head Loss ~ 37' (assumes 100' of pipe and typical fittings for a spa)
  • Desired Pump Operating Point = 90 GPM @ 37' of head

Learn Pool Plumbing with Test Tank is a YouTube video from JMax Swimming Pool Plumbing that demonstrates how spa jets with an air venturi work. It also gives a great demonstration of pool hydraulics and what head is.

The Ultimate Guide to Gunite Jet Body Installation explains how gunite jet bodies are installed and jets assembled.

Spa Dual Pump Plumbing

When a spa has many jets a dedicated spa jet pump maybe needed to give adequate flow without the restrictions of a filter or heater. Below is typical plumbing for spas serviced by dual pumps.

One pump provides filtered and heated water to one or two spa returns. The other pump flows directly to the spa jets. Each pump has dedicated suction ports in the spa floor.

Spa Dual Pump Plumbing.png

2 Inch PVC for the Equipment

If you have 2" fittings at the pump amd filter use 2" PVC for the equipment. Then make your return manifold out of 2" and then use 1.5X2" diverter valves as reducers to 1 1/2" return pipes.

Valves

Use re-buildable diverter valves such as from Jandy, Pentair, Hayward, or CMP . The "ball valves" found in big box stores are not recommended as they are problematic, stick over time, handles can break, and are difficult to repair.

Unions

All of the equipment should be connected with unions for cost savings over time, and for repairs to occur without cutting the pipes. The extra cost up front will prove useful the first time a repair is needed.

For Pentair pumps look for "2 PACK -CMP Hi-Temp Union 2" inch 2MIP x 2" inch PVC Whisperflo & Intelliflo - 2 PACK"[10]

Labeling of all Pipes and Valves

Additionally, all valves and pipes should be labeled for function and flow direction, with permanent labels or light engraving. For good measure take a picture and print it out in case the labels fade or fall off.