Building a Pool Cooling Spray Cannon

Building a Pool Cooling Spray Cannon

Instructions for building pool cooling sprayers on a pool.

*Works best with a variable speed pump.
*One to two sprayers will work fine for most pools – This pool is 85,000 gallons and benefits from the 4-spray configuration for more evaporation.
*Requires restricting or plugging of other ports on multi-return pipe runs.
*Raises System PSI (for our system, the filter pressure rises from 10PSI normal operating pressure to 12PSI sprayer pressure).
*Raises acid consumption slightly (not too noticeable, but we do use a little more acid as aerating the water tends to make the PH rise in a pool
*Adjust the angle of the spray by loosening the union and aiming the nozzle to the desired location in your pool.
*Video at the end doesn’t have the cannons running at full power – but they can spray over the back wall when the pump RPM is high enough.

***CAUTION: Carries risk of deadheading pump and damaging plumbing if you use a fire hose nozzle that will completely close (and inadvertently gets closed while the pump is running). Recommend using two heads or leaving one return just partially restricted to reduce deadhead risk***

For our pool (if left to run without sprayers) it normally rises up over the course of a few days to 93 or 94 degree water temp during the summer months. (It sits in the sun the majority of the day.)

We run the sprayers from 8:30pm to 8:30am each night and it takes the temperature down from a typical 86 (5 degree heat gain from 1 day) down to 80 or 81 degrees by morning.

We pull water 90% from the skimmers and 10% from the main drain – to take the warmest water off the top and throw it through the air for evaporation. This leaves the colder water intact in the lower levels of the pool water column. There is a noticeable “thermocline” during the day as we don’t run the pumps much in the daylight hours.

Parts list:

Fire Hose Nozzle:

Fire Hose Nozzle Thread Adapter to NPT:

1.5″ x 10′ Sch 40 PVC Pipe: Home Depot Item 100135041

1 x 45 degree street elbow: Home Depot Item 100677990

1 x 90 degree street elbow: Home Depot Item 203822499

1 x PVC Union: Home Depot Item 204202883 (This allows the sprayer to be rotated and aimed)

2 x Slip to Thread Adapter: Home Depot Item 100347535

X number of 1.5″ plugs: Home Depot Item 100346681 (to restrict flow out of other returns on pipe circuit)

PVC Cement: Home Depot Item 302473009 (This is single step so no priming – and it’s clear)

Cut pipe for connections between street elbows and union using a saw. (Adjust lengths of cut pipe segments to ensure the top of the fire hose nozzle clears the water line by a couple inches.)

Glue pieces together as shown in video.

Thread into wall return.

Plug remaining returns on same return circuit.

Start Pump on low rpm and increase the rpm until the water arcs over pool but doesn’t over-spray the edge of the other side of the pool. Save RPM in program and schedule it to come on during the night.

Multiple heads can be attached to single port using pvc fittings shown in video. This is not generally needed with most pools though. If anything, I would recommend putting two single sprayers on opposite ends of the pool on the same circuit for additional cooling on a typical sized residential pool.


Video Building a Pool Cooling Spray Cannon

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