Fafco Solar Panel - Recommendations

bhollehday

Active member
May 22, 2020
37
Palmdale, CA
Id like to add solar to a slope that is adjacent to my pool equipment. Id like to know if there is any real difference in plumbing the panels horizontally or vertically. I read that I can do both by removing diverting plates that allow you to mount horizontally (ideal for above ground pool). Is there any advantage to doing one over the other?

3 concerns:
1. I have 2” piping on the equipment, but solar is 1.5". Should I pipe 2" to the panel or neck it down to 1.5" right away?
2. I don't need to drain the panel unless there are freezing conditions correct? Ill have to add a manual drain it doesn't get that cold here.
3. Id like to plumb the solar after the heater with the solar to allow for better flow. Maybe this will help the 1.5" reduction?
 

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riny

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Well I'm no expert but I have two of these panels so I'll give it a shot:

1. I have 2” piping on the equipment, but solar is 1.5". Should I pipe 2" to the panel or neck it down to 1.5" right away?

In general, you want to reduce as late as possible. The 2" pipe will have less head loss due to friction. So it will be more efficient to run the 2" to your panels and only reduce when you get there. Practically speaking though, this probably only matters over longer distances. If your panels are very close to your pool then it might not matter so much.

I don't need to drain the panel unless there are freezing conditions correct? Ill have to add a manual drain it doesn't get that cold here.

Correct but make sure you have room for expansion. If you have isolation valves on the solar loop for example, don't close the valves fully if the panels are full of water.

Id like to plumb the solar after the heater with the solar to allow for better flow.

Do you mean that you also have a traditional gas or electric heater? If so, you generally want to plumb the solar in FIRST, and then the heater after. The heat from the solar is free, so you only want to use your heater to make up any difference that the sun doesn't provide. If you plumb your heater in first, then the water will already be up-to-temperature before it even hits the solar panels.
 
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CJadamec

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I have mine horizontal and they work just dandy. You need to tilt them a bit so the water will better drain out for winterizing if that is a concern. I also found you need to let one side of the panels "float" on the surface they are mounted to. The panels themselves shrink and expand a lot as they heat and cool. If the end headers are mounted rigidly it puts a lot of stress on them.

All my plumbing is 1.5" and I'm ok with that.

My solar panels feed warmed water into my heat pump. It keeps the heat pump from running when it's not needed. Would much rather get the free heat from the sun rather than pay for electricity.

4 years now with the panels and I would do it over again in a heartbeat.

PXL_20210515_132236642.jpgPXL_20210515_140212325.jpg
 
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bhollehday

Active member
May 22, 2020
37
Palmdale, CA
Correct but make sure you have room for expansion. If you have isolation valves on the solar loop for example, don't close the valves fully if the panels are full of water.

Ok. What is the point of even using isolation valves? What's the difference in just keeping the equipment off and bypassing the solar with the 3-way valve? I wasn't planning on using any isolation valves.

Do you mean that you also have a traditional gas or electric heater? If so, you generally want to plumb the solar in FIRST, and then the heater after. The heat from the solar is free, so you only want to use your heater to make up any difference that the sun doesn't provide. If you plumb your heater in first, then the water will already be up-to-temperature before it even hits the solar panels.

Yes. I read that the heater has its own pressure loss and if it were to be bypassed you'd get more flow. Maybe its marginal, but that it wouldn't hurt. The way my heater works (maybe I'm wrong) with Pentair's intellicenter is it reads the temperature at the outlet of the pump and either turns on or off the heat from there. So it wouldn't make a difference would it? Unless I were to use the heater manually and then utilize the heaters internal temperature reading?

Also I planned on using CPVC plumbing and 3-way valve up to the equipment. I live in SoCal desert and it gets 110+ out here in peak summer.

I have mine horizontal and they work just dandy. You need to tilt them a bit so the water will better drain out for winterizing if that is a concern. I also found you need to let one side of the panels "float" on the surface they are mounted to. The panels themselves shrink and expand a lot as they heat and cool. If the end headers are mounted rigidly it puts a lot of stress on them

That's great to know! So from my understanding these can be ran either direction by opening the bypass valve built into the panels and cutting the ends off? I plan on connecting 5 panels, and feel like it might be easier to run the vertically on the slope rather then horizontally. I could also fit more square footage if I do this. Seems like it would drain much easier as well and wouldn't pool up inside the hoses. What do you think?


I was planning on using Pentair's 3-way drain down valve, but since the pool equipment would be adjacent to the middle of the solar and at the same height, I don't think this is needed, do you guys concur? Its not going to be able to drain back as the inlet to the solar will be below the height of the pump (about 4-5ft). So I don't need the vac release or the drain down style valve? Or maybe the drain down is a good idea to allow for expansion, just in case (its same price anyways)?
 

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CJadamec

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My panels do not have plugs in the headers. They are all run in parallel. That is the most efficient way to run solar panels. Water goes in one side of all 3 panels and exits on the other side.

I have a vacuum relief valve. They are cheap and easy and allow automatic draining.

I don't have isolation valves. Directly off my filter is a check valve follwed by the 3 way diverter. The diverter directs water to either the solar panels or thru the heat pump and back to the pool.

There is another check valve on the return from the solar panels which prevents water from going backwards into the panels when the diverter is closed. The return from the panels tees into the inlet of the heat pump.

I don't see a reason to bypass your other heater when the solar panels are in use. To each their own on that one. There are plenty of times when both my solar panels and heat pump are running at the same time.
 
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bhollehday

Active member
May 22, 2020
37
Palmdale, CA
My panels do not have plugs in the headers. They are all run in parallel. That is the most efficient way to run solar panels. Water goes in one side of all 3 panels and exits on the other side.
So these are the panels I plan on buying:

They are setup to return to the same side as the feed for ease of use on above ground pools. But im pretty sure I can make them work to feed conventionally with feed on one end and return on the other end.


I don't see a reason to bypass your other heater when the solar panels are in use. To each their own on that one. There are plenty of times when both my solar panels and heat pump are running at the same time.

Ok now its making sense to me. If I do it as I drew it, I can really only use solar OR gas heater. Cant use both. If I plumb before/after the heater then I can use both. And it sounds like it would be better the plumb before, that way if it were ever used in manual mode then the heater is reading the gas heater temp PLUS the solar.
 

CJadamec

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riny

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Ok now its making sense to me. If I do it as I drew it, I can really only use solar OR gas heater. Cant use both. If I plumb before/after the heater then I can use both. And it sounds like it would be better the plumb before, that way if it were ever used in manual mode then the heater is reading the gas heater temp PLUS the solar.

It's not really about manual mode. Say you want to keep your pool at 84 all the time. First you want the water to circulate through the solar panels. (In parallel, like @CJadamec said. Use a manifold or some tees to split your inlet among all of the panels, then again on the outlet side to join them all together. Do NOT plumb them in series, outlet-to-inlet, like you would with Christmas lights.)

Then plumb the outlet from your panels to the inlet of your gas heater. This way: if the solar panels are enough to heat the water to 84, then there's nothing for the gas heater to do. Let's say it's a cloudy day though and the solar only gets you to 80. In that case, the gas heater can just make up the remaining 4 degrees.

You want to use the heater's temperature sensor, which measures the water temp coming in, after it's been heated by the solar. If you're using the Intellicenter to drive the heater, then you might consider using the Intellicenter's solar capability. This is designed to work with an air temperature sensor and an actuated 3-way valve, so it only sends pool water through the panels if (a) the water is under temperature, and (b) the sun is shining. If you circulate water through your panels on a cloudy day, then they'll be cooling your pool instead of heating it.

What is the point of even using isolation valves? What's the difference in just keeping the equipment off and bypassing the solar with the 3-way valve? I wasn't planning on using any isolation valves.

You want a way to completely cut off water flow to your solar loop. The panels aren't indestructible and one of them might spring a leak, for example, or get clogged by some gunk that makes it through your filter.

You can do this with a 3-way and a check valve as long as they're both positive-seal. When I first hooked mine up, I made the mistake of using those white Hayward Trimline ball valves, because that's what they had at the pool store and I didn't know any better. The problem is they don't fully seal. I wanted to blow out my panels and bring them inside for the winter... but I couldn't disconnect them until the pool was winterized, because water would trickle out of those valves.

I'm replacing the whole setup this year and using only Jandy Neverlube valves everywhere. I'm not hooking my Fafco panels back up again so I'd sell them to you cheap, if you were closer. :)
 
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bhollehday

Active member
May 22, 2020
37
Palmdale, CA
It's not really about manual mode. Say you want to keep your pool at 84 all the time. First you want the water to circulate through the solar panels. (In parallel, like @CJadamec said. Use a manifold or some tees to split your inlet among all of the panels, then again on the outlet side to join them all together. Do NOT plumb them in series, outlet-to-inlet, like you would with Christmas lights.)

Then plumb the outlet from your panels to the inlet of your gas heater. This way: if the solar panels are enough to heat the water to 84, then there's nothing for the gas heater to do. Let's say it's a cloudy day though and the solar only gets you to 80. In that case, the gas heater can just make up the remaining 4 degrees.

You want to use the heater's temperature sensor, which measures the water temp coming in, after it's been heated by the solar. If you're using the Intellicenter to drive the heater, then you might consider using the Intellicenter's solar capability. This is designed to work with an air temperature sensor and an actuated 3-way valve, so it only sends pool water through the panels if (a) the water is under temperature, and (b) the sun is shining. If you circulate water through your panels on a cloudy day, then they'll be cooling your pool instead of heating it.



You want a way to completely cut off water flow to your solar loop. The panels aren't indestructible and one of them might spring a leak, for example, or get clogged by some gunk that makes it through your filter.

You can do this with a 3-way and a check valve as long as they're both positive-seal. When I first hooked mine up, I made the mistake of using those white Hayward Trimline ball valves, because that's what they had at the pool store and I didn't know any better. The problem is they don't fully seal. I wanted to blow out my panels and bring them inside for the winter... but I couldn't disconnect them until the pool was winterized, because water would trickle out of those valves.

I'm replacing the whole setup this year and using only Jandy Neverlube valves everywhere. I'm not hooking my Fafco panels back up again so I'd sell them to you cheap, if you were closer. :)

Got it thank you. Why are you not hooking up your fafco panels? Are you switching?

I plan on running the fafcos vertical on the slope, leave the ball valve open on the fafcos and connect 6X panels end-to-end (that way they flow like a conventional panel would). I will feed the panels from the bottom of the slope, and the outlet will be at the top of the slope. One thing I am wondering is if I should feed the panels from the near end to the equiptment and outlet on the far end, as shown in the pic. I saw professional installer at my sisters house do this on her sloped roof (im thinking it must equalize the flow/pressure across the panels more evenly? Or I wonder if it has to do with draining?).

vertical2.jpg
 

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CJadamec

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The way you have it drawn is the right way to feed the panels. Cold in on a bottom corner, heated water out on the opposite corner on top.

Plumbing that way forces the air bubbles out of the panels and best distributes water across all the panels.

Always run the plumbing with a plan for how it will be drained for the winter. Avoid forming traps that will hold water.
 

riny

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Aug 20, 2020
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Why are you not hooking up your fafco panels? Are you switching?

Yeah I never really had a good place to put them. The roof is too far away and we put in a patio this year so the layout just doesn't work. I'm installing an FPH instead.
 

bhollehday

Active member
May 22, 2020
37
Palmdale, CA
Does anyone have any opinion on mounting these panels? I was thinking about laying them directly on the ground and just run a 2x6 to mount the upper header. I was thinking id till the slope and lay an underlayment down. I was thinking about building a rack to get it off the ground but running 3-4 rows of 2x6's perpendicular to the slope, but im thinking unless you use 4x8' sheets on the rack, then you might be better off putting on the ground in order to take stress off of tubes from expansion?1.jpg2.jpg
 

CJadamec

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You should mount them on a rack if at all possible. The ground will act as a heat sink.

Plywood would be best under the panels but at the cost it is today I'm not sure I would use it.

As an alternative rack type system I would run your 2x6s length wise on the panel then use 1x2 strapping spaced out every 4 inches or so to support the panels.

That would help cut down on the material costs. You need to support the panels as well as allow them room to shrink and grow as they warm up and cool down.
 

bhollehday

Active member
May 22, 2020
37
Palmdale, CA
You should mount them on a rack if at all possible. The ground will act as a heat sink.

Plywood would be best under the panels but at the cost it is today I'm not sure I would use it.

As an alternative rack type system I would run your 2x6s length wise on the panel then use 1x2 strapping spaced out every 4 inches or so to support the panels.

That would help cut down on the material costs. You need to support the panels as well as allow them room to shrink and grow as they warm up and cool down.

Is it really worth the extra $600 in lumbar to get it off the ground for efficiency?
 

CJadamec

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Is it really worth the extra $600 in lumbar to get it off the ground for efficiency?

You will get more heat into your pool and the panels will have something to hold them in place.

Its also a long term installation those panels will be there for years. Mounting them neatly on a raised surface goes a long way towards keeping everything clean and decent looking.

Its your wallet though and lumber ain't cheap these days.
 

riny

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You could probably do it out of PVC too, for a lot cheaper. I've seen this picture online:

basic-solar-rack.jpg
 

Woodstock1234

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Aug 4, 2020
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Yep, mounted mine with pvc. Much cheaper than wood these days. I don't think the efficiency gain is that much from being off the ground. Only reason I did it was cause they were on the ground for 2 days and my son decided it was ok to step on them. Oy.
 

bhollehday

Active member
May 22, 2020
37
Palmdale, CA
Ok sounds good. Ill look into that. What about for a hot desert climate, I live in socal and it gets 110 in the summer. Am I stuck using CPVC? Or can I use PVC?
 

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