Roof Mounting Solar Panel Pipe Sizing

[north swimmer]

I want to install a solar collector on the roof.

I have bought the SmartPool SunHeater model S425P , 2 collector 2’ x 20’

According to the sunheater manual , no vacuum breaker is required

The actual layout is: skimmer -> pump -> filter -> salt system -> pool return

which size should be the PVC pipe to go to the solar collector ( 1.5” or 2” ) ?

Pool : Above ground 15’

Pump : Hayward 1.5 HP, model Ultra-Max sp2915

Salt system : Intex

Total height to the roof 15’ , distance 9’ (from the filter to the wall)

Actual pipe size is 1.5"

Pressure at the filter:

With the salt system: 15 PSI

Without salt system : 12 PSI

Should I install the solar panel before or after the salt system ?

Is it ok not having a vacuum breaker ?

Thank !

[quantumchromodynamics]

which size should be the PVC pipe to go to the solar collector ( 1.5” or 2” ) ?

What is the design flow rate range for the panels? Minimum and Maximum?

What is the head loss from the panels at the minimum and maximum flow rates?

Pump Output (GPM) vs. Total Resistance To Flow (Feet of Head)

Model Number...10 ft........20 ft.........30 ft....... 40 ft...........50 ft.

SP2915............. 65gpm.... 57gpm.... 45gpm..... 30gpm...... 8gpm

HaywardCanada

Your return head is already 34.6 feet (15 psi). That's not including suction head or the additional head that will be added with the solar. Adding another 15 feet of head will be close to maxing out your pump.

You want minimize the pressure on the panels. Were you planning to put the entire flow through the panels?

Should I install the solar panel before or after the salt system?

The solar panel should be after the filter and before the SWG.

Is it ok not having a vacuum breaker?

This installation manual for another one of their systems shows a vacuum relief valve. I think that you should use a vacuum relief valve. The panels need to drain when not in use.

Contact the manufacturer and ask them why your system wouldn't need a vacuum relief valve. Also, ask about flow rates and head loss.

Pressure at the filter:

With the salt system: 15 PSI

Without salt system : 12 PSI

Are you using restrictor/directional eyeballs in your returns?

What is the make and model of your filter?

Have you cleaned your salt cell recently?

[north swimmer]

Thank for the reply !

Are you using restrictor/directional eyeballs in your returns? YES

What is the make and model of your filter? Hayward S210T

Have you cleaned your salt cell recently?

I have done some pressure test:

Filter in recirculate mode, no eye ball, no SWG , pressure = 6.5 PSI

Filter in filtering mode, no eye ball, no SWG , pressure = 10 PSI

Filter in filtering mode, no eye ball, with SWG , pressure = 12 PSI

Filter in filtering mode, with eye ball, with SWG , pressure = 15 PSI

So the eye ball add 3 PSI and the SWG add 2 PSI

The SWG can run with a minimum flow of 11 GPM, i actually run it when the pump is at low speed.

I guess i could install a by-pass valve to limit the flow going to the SWG

You want minimize the pressure on the panels. Were you planning to put the entire flow through the panels?

On the installation guide , the entire flow pass through the panels, but since i will install a diverter valve to turn on/off

the collectore i could adjust it to limit the flow.

I have post a request to SmartPool to get the min and max flow as well as the head loss. Didn't have a response yet ...

[quantumchromodynamics]

I think that you could use 1.5-inch PVC to go to the solar if the flow rate going to the solar is 30 gpm or less. If it will be over 30 gpm, use 2-inch PVC. The primary downside to going 2-inch is that the pipe will weigh more than 1.5 -inch.

15 foot of 1.5 inch PVC = 7.7 pounds (PVC) + 13.3 pounds (water) = 21 pounds.

15 foot of 2-inch PVC = 10.2 pounds (PVC) + 21.8 pounds (water) = 32 pounds.

The pipe should be marked Schedule 40, ASTM D1785, which specifies pressure rated pipe. The pipe might be dual rated ASTM D-2665, which specifies drain, waste and vent.

The pipe should also be marked "NSF-PW", which specifies that the pipe is certified by the National Sanitation Foundation (NSF International) as suitable for Potable Water.

You could get a flowmeter to verify the actual flow going to the panels to make sure that it is within the specified design range. The pressure at the vacuum relief valve should be slightly positive without going too high. You want to adjust the pressure after the panels to achieve the slightly positive pressure at the vacuum relief valve.

The primary issue that you have is that your pump is not designed for high pressure applications. Your pump tops out near 50 feet of head where many other pumps of the same HP will get closer to 70 feet of head. The Hayward Super II will get up to about 80 feet of head.

Another issue that you have is that your filter is a little bit undersized for your pump (or your pump is a little bit oversized for your system (without solar). Your filter design flow rate is 44 gpm.