Solar Heater Plumbing Design Questions

kesham13

Member
Mar 15, 2017
7
Tucson, AZ
Hi All! This is my first post, but I have learned a ton from the collective knowledge on these boards. We just built a pool in our yard (I'm not a newbie - we had a pool at our last house and I had one growing up) and while we have a trench dug and existing pavers pulled up, we considered putting in a solar system. Price dictated that we were going to do this ourselves and after reading a ton of information, I'm confident we can do it. I do need to get some plumbing in though before our pavers get put back together, so hoping you can all help me with my layout to make sure it makes sense.

I attached a rough diagram, but will describe what I'm thinking just so it's clear:

We have a long run from our equipment to our pool, maybe 50 feet or so. The pump, filter, controls and SWG are already installed at the location in the top right. The return line to the pool runs perpendicular to where the trench is for the autofiller and there is room to add more pipe. So I'm thinking I will cut the return line and put in a loop to the solar, with a check valve, then a 3 way valve, then the supply will run up the wall, under the eaves, and to the patio roof. The patio roof is mostly flat (white, elastomeric coated), but we do have gutters so there is a slight slope to it to help with drainage when it rains.

I proposed plumbing the supply line in on the right, bottom and putting a vacuum release valve just before the supply connection to the panels. I want to run the panels in parallel, though the ones I bought are designed to be in series. I think I can remove the baffle in each panel which is designed to force the water to go up, then back down each panel (it's just a plastic disc with a hole, which I should be able to take out). Ideally, the water would run through the panels, up to the top, then out the heater return, back down the eaves and wall, then cut back into where the original return line went to the pool.

Questions I have are:

1.) Do I need check valves in both places where I indicate? Do I need the 3 ball valves a lot of diagrams show?
2.) Is the VRV appropriately placed? Should I put it on the top right solar panel instead?
3.) Will I have problems plumbing in and using water that has already gone through the SWG? There is no way I can plumb the SWG after the heater lines without a significant change.
4.) Will the 3 way valve need to be drilled with 1/8" inch bit to make it "leaky?" Is the check valve just before the 3 way valve in the correct spot?
5.) Would you swap the input and output sides? I'll just have to figure out how to cross the pipe runs if I do that.
6.) Anything else I'm missing or should consider?
 

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jblizzle

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May 19, 2010
41,195
Tucson, AZ
:wave: Welcome to TFP, neighbor!!!

Your setup will be pretty similar to mine.
To your questions:
1. Yes, you need a check valve after the filter and before the solar 3-way valve and you need a check valve on the solar return line prior to teeing back into the main plumbing
2. The VRV can go just about anywhere. I put mine right about the same place you have it drawn.
3. Shoot, missed this. You can not do that as explosive gas may build up in the solar panels. The SWG needs to be the last thing before going back to the pool.
4. You could, or you could add a crossover that would allow the supply side to drain into the return pipe. Check valve can be anywhere between the filter and 3-way
5. You will save a little more heat by having the supply to the far side of the panels and the return on the near side. It is actually pretty easy to get them to swap as you go up and over the eave.
6. Make sure the panels are all slightly tilted so the air will get pushed out the return pipe. Can not think of anything else off-hand. Biggest issue is you really need the solar loop to go back to the pad and tie in before the SWG.
 

kesham13

Member
Mar 15, 2017
7
Tucson, AZ
Thanks for the reply jblizzle! Makes me feel better! And glad to see there are lots of other Tucsonans on these boards.

Sounds like I just need to bite the bullet and add the extra plumbing to tie back at the pad. Bummer, but not really that big of a deal, probably and extra 30-40 feet of pvc combined. Definitely better than explosive gas building up in the panels. Hopefully I will still have plenty of flow running the pump at 1/2 or 2/3 speed because my runs are already pretty long. Glad we went with 2 inch pipe.
 

jblizzle

Mod Squad
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May 19, 2010
41,195
Tucson, AZ
Remember for optimal solar heating you want high flow rates. You likely can run at a lower speed but won't add add much heat. Do you have a solar controller?
 

kesham13

Member
Mar 15, 2017
7
Tucson, AZ
I wasn't planning on having a solar controller due to the 3 way valve being away from the rest of the equipment and in a location without power. With the change in the plumbing, now I could put the 3 way valve right next to the equipment and might look into adding a solar controller.
 

pooldv

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You can run the wire over with the plumbing. It is a low voltage wire and can be run however far you need it. A solar controller will help a lot with heating up the pool because solar panels can cool a pool just as fast or faster than they can heat a pool. My solar turns on and off multiple times per day, especially during spring, because of rain and clouds. Solar panels can go from 110 in the sun to 65 in the rain in just a few minutes. The solar controller will close the valve and preserve the heat.
 

domct203

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I wasn't planning on having a solar controller due to the 3 way valve being away from the rest of the equipment and in a location without power. With the change in the plumbing, now I could put the 3 way valve right next to the equipment and might look into adding a solar controller.
+1
If you are going to invest in solar, the controller is a must. The controller will make sure that on cloudy/cold days you are not cooling the pool. Also, the valve actuator does not need a separate power source, it gets its power form the controller.
 

kesham13

Member
Mar 15, 2017
7
Tucson, AZ
Thanks everyone for your replies! Looks like the controller I have (Hayward PL-Plus-20g) is already able to control the solar, so all I need is an electronic valve actuator and I should be good to go (already have a Jandy 3-way valve and a temperature sensor).

Can you mix and match a valve and actuator? Do I have to buy a Jandy actuator or can I get any of them and it will fit together? Should I stick with a Hayward actuator since the controller is Hayward?
 

pooldv

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Any actuator will work fine, hayward, pentair, jandy. It is the one thing in the pool world that is universal. :)
 

jblizzle

Mod Squad
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May 19, 2010
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Tucson, AZ
Intermatic is another actuator that has a more reasonable cost. Like said above, brand does not matter.

Great that you already have the controller, It helps with the heating. After all while it is the 90s now, in a few days it is going to be windy and in the 70s so there may not be heat to add. Would you remember to manual turn off the solar?

Also note that you want the solar temp sensor to be on the roof with the panels. So you will need to buy some shielded 18ga twisted pair wire to extend that sensor wire and bury it with your solar plumbing.
 

domct203

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Jun 3, 2015
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Thanks everyone for your replies! Looks like the controller I have (Hayward PL-Plus-20g) is already able to control the solar, so all I need is an electronic valve actuator and I should be good to go (already have a Jandy 3-way valve and a temperature sensor).

Can you mix and match a valve and actuator? Do I have to buy a Jandy actuator or can I get any of them and it will fit together? Should I stick with a Hayward actuator since the controller is Hayward?
You will also need two temperature probes, one for the pool water and one mounted at the solar panels.


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