pipe size for coils?

[Wade1]

details:

pool is 21' above ground, 2" pipes at the pump/filter which i plan to divert into home made coils and then back into the pool.

i read somewhere that i should try for 50% of the square footage of the surface area of the pool and that 100' of black poly pipe coil is equal to aprx 25 sq feet (so i need 7-8 100' coils?) this sound about right?

based on that, should i be using 1/2", 3/4" or 1" poly pipe for the coils?

[Naptown]

details:

pool is 21' above ground, 2" pipes at the pump/filter which i plan to divert into home made coils and then back into the pool.

i read somewhere that i should try for 50% of the square footage of the surface area of the pool and that 100' of black poly pipe coil is equal to aprx 25 sq feet (so i need 7-8 100' coils?) this sound about right?

based on that, should i be using 1/2", 3/4" or 1" poly pipe for the coils?

Use 1/2" but limit coil length to 50'

[Wade1]

i take it there is no temperature gain after 50' ?

will 8 coils still be enough (or is "the more the merrier"?)

i understand to run them in parallel rather than in series, but will the pressure remain constant throughout all the coils (regardless of how many coils i use)?

thanks again

[Mike90250]

You have to construct a decent header for the inlets and outlets. Think of the distribution box at either end of a car radiator - they are sometimes called "End Tanks" to allow the water to flow evenly through all the pipes.

[Wade1]

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shamelessly stolen from another thread,

so do the header/tank pipe sizes matter?

or just use the same 2" feed on both the inlet and outlet side of the coils?

or should the end tank be slightly smaller (1 1/2") to create back pressure and allow all the coils to fill? or larger (3")

thanks again, reading as much as i can, so sorry if this is covered somewhere already

[russ]

The header should not be the cause of pressure drop - it should be larger than the coil/exchanger and the same size on both ends should do fine.

[Wade1]

so 1" pipe for header/end tanks, 1/2" for the coils @ 50' lengths, will 8 coils still be enough?

thanks

[Naptown]

2" or 1 1/2" for the headers the same size as the pool piping.

[tonytheroofer]

I used 1/2 poly , because I had that locally however using 3/4 can not hurt you. I also used 100 ft runs of poly and I had no flow issues with 5 100' coils connected into 1 1/2 headers. Fact is that system worked very well,my pool was always warm and I never needed a solar cover during the height of the season,matter of fact at times I wished the water was a tad cooler !


Now I just set up (6) 2 x 20ft solar heaters for above ground pools that I removed the internal diverter from and hooked them all together. With the coils I used a 5 gal bucket and a stop watch , ( Scientific it is not ) however with the system fully flowing it would take 10 seconds to fill the 5gal bucket and with the pre- made solar heaters I am at the same time give or take a few hundredths of a second . I only mention this because good flow is what you need to transfer the heat from the tubes or solar heaters. Additionally when I touch my system coil or solar heater it remains cool to the touch which is telling me I am drawing the heat absorbed away from the plastic and dumping it into the pool where i want it.

So use 3/4 and dont fret on the 100' runs because it reduces connection points by half , leak possibilities by half and work by half which when doing a DIY project has a lot of value.