Pumping using dual speed 1HP pump to solar panels on roof

[robsnyder20]

Has anyone hooked up a 1HP Pentair WFDS-24 dual speed pump and ran it on low to pump up to their solar panels mounted on the roof before? Not sure if this would work or not? I always leave my pump on low except when running the vacuum and was wondering if this would work or if I would have to run it on high or get another pump to do the job? I would be looking to add about 320 square foot of panels up about 10'-15' high on the roof for my inground pool 15x30 with 1.5 inch pipe. Let me know what you think as I think I am going to get solar for my pool this year with my tax return money.

Also, if anyone has recommendations on which panels to get that are good in the florida sun with shingles, let me know! I am looking to do it myself! Thanks in advance!

 

[susa]

Can't answer your question but have considered installing a small test of solar and hooking panels/lines using the spare capacity of the IntelliFlow VF.

Is that really a tab feeder you're using, Pentair Rainbow 320 ? I ditched all tabs in favor of liquid and installed IC40. Keeps the Cyanuric Acid in check too.

 

[robsnyder20]

In regards to the chlorinator, yes I have bought one of those at some recommendation of friends that had them but now I know better. I'm not sure how bad stabilizer is but I know mine is maxed at 100 right now! I have considered buying the liquidator now that I am buying chlorine at a cheaper rate from another pool supply place $3 per 2.5 gallons. I also know I have to add acid every other week to the pool as well.

 

[susa]

> also know I have to add acid every other week to the pool as well.

am really happy I installed the Simpool PH (link on sigline) which totally automates the pH and allows me to just simply swap out a new bottle from Home Depot once or twice a month.

 

[mas985]

You can get a pump on low speed to work with solar but there are few things you need to take into consideration.

First, the solar panel efficiency is much lower when the pump is on low speed so you won't get as large a heat gain on low speed than high speed.

Second, if your panels have a vacuum release valve, it will need to be installed a few feet above the pump on the supply line. This is because low speed of a pump does not have enough pressure to keep the valve closed when it is on the roof.

Third, you will need a controller that allows the pump to prime the panels on high speed and then drop down to low speed after they are primed. This is the hard one. Most automatic controllers will force the pump to high speed when there is solar demand. You might be able to wire a mechanical timer of sorts to change speed after a certain amount of on time. Variable speed pumps/controllers do not have this problem as you can set any speed you want for any function that you want.

 

[Prav]

Not to go off-topic... but, Rob - where in Fla. are you that you can get 2.5g of Cl (10% at least since from pool store) for $3?

 

[susa]

> where in Fla. are you that you can get 2.5g of Cl for $3?

am a few hours further south but I pickup 15 gallons for under $20.00 using local store discount program(s)

 

[robsnyder20]

Re: Pumping using dual speed 1HP pump to solar panels on roo

To answer the question, I buy my chlorine from five star pools which is closer to me in Port Charlotte, FL than Pinch a Penny. It supposedly is 10.5% chlorine which is the same as Pinch a Penny. Jugs they use seem to be cleaner and in better shape than Pinch a Penny as well.

Still never went solar yet, but would love to move my temps from the current low 80s to the high 80's+

 

[JamesW]

Re: Pumping using dual speed 1HP pump to solar panels on roo

Mas985, wouldn't putting the vacuum release lower cause excessive vacuum in the panels?

 

[mas985]

Re: Pumping using dual speed 1HP pump to solar panels on roo

Yes, it will put a slight negative pressure in the panels and the panels may deform some but it shouldn't be all that much. Some solar installers have installed the VRV at pad level for easy replacement and have done this for years without problems but in some parts of the country where it gets really hot, one installer told me that there have been problems with the PVC return collapsing on two story roofs. If flow to the panels are shut off while the pump is still running and the water is allowed to remain in the panels/pipe and heat up to very high temps where the PVC starts to soften, when the pump shuts off, there is a slight vacuum and if the PVC is soft enough, it could collapse under the vacuum. The material of solar panels tends to have a much higher melting point than PVC so risk of permanent collapse is much lower than what it is for PVC. But again, this seems to happen only in extreme temperature conditions where the water in the pipes can get hot enough.