DIY solar using Sonoff

Digging the trenches and fitting the PVC was tough for a man of my advancing years. I think running it underground is not ideal for this application but heck 90% of the plumbing runs underground. I have valves strategically placed to flush any water that sits in the pipes too long before it can get to any complex systems or the pool itself. I'll have to keep up on my chlorine. I found that dry fitting all the PVC in the trenches, indexing the 45s and 90s with a sharpie (a line across the joints) then removing and gluing it in a more comfortable location worked well for me. Then just drop it back in and make a few final connections. No leaks. I have 2 slow leaks on the threaded caps on corners of the panels. Guess I'll have to unscrew em and gob some more sealant in there. Also had to tighten one of the hose clamps that had a little geyser. I can't imagine doing that up on the roof.
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Digging the trenches and fitting the PVC was tough for a man of my advancing years. I think running it underground is not ideal for this application but heck 90% of the plumbing runs underground. I have valves strategically placed to flush any water that sits in the pipes too long before it can get to any complex systems or the pool itself. I'll have to keep up on my chlorine. I found that dry fitting all the PVC in the trenches, indexing the 45s and 90s with a sharpie (a line across the joints) then removing and gluing it in a more comfortable location worked well for me. Then just drop it back in and make a few final connections. No leaks. I have 2 slow leaks on the threaded caps on corners of the panels. Guess I'll have to unscrew em and gob some more sealant in there. Also had to tighten one of the hose clamps that had a little geyser. I can't imagine doing that up on the roof.
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It all sounds very rewarding. Nice job.

Are you talking about the solar plumbing underground? And worrying about it off-season? Mine runs underground for a bit. I drain all but whatever is below about an inch above ground in the fall, but the water that's underground stays there all winter. I don't worry about it. It's chlorinated and free from sunlight. Our frost lines are about the same, 5", yours might even be zero. It'll be fine. Or blow it out if you think it's going to be a problem. That's how they ready pools for winter "up north."
 
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If it takes 3 hours to heat the spa 12 degrees it take 12 hours (~2 days) to heat my pool 1 degree? That can't be right. I need another array...
Possibly. But keep in mind: any time your array cannot heat the pool, it is actually cooling it. This time of year I hear my pump ramping up and down. My controller varies my pump's RPMs, so it goes 2200 for solar on and 1500 for solar off. So I know my array doesn't always have enough heat to add any to the pool. Which means without a controller, if I just ran the solar non-stop, some hours of the day it'd be adding heat, but the rest of the hours it'd actually be cooling the pool. Depending on the day, I might get the same 1° difference you just got, or worse, I could lose heat.

Sorry to keep harping on the controller, but I still think you're not fully appreciating what they can do. I'm not saying your MO won't warm up your pool, it will, I'm just reminding you you're never going to be able to simulate the fine tuning a dedicated solar controller can do. I'm having a similar conversation with another of our fellow TFPers. He's trying something similar as you. He's got his system checking temps every 15 minutes, but that's not going to always work out either. A dedicated controller is constantly checking, and might turn off the flow for only ten minutes at a time. But that's 10 minutes this other guy will be cooling his pool!

During the summer, I'm guessing your systems will work just fine. It's these fringe-months where a controller really shines, when the air is in the 70s, and there's a a little cloud cover, and you're trying to eek out every degree you can.

It's just a matter of the right tool for the job. You can pound in a nail with a wrench. But you'll do it better and faster with a hammer.
 
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Had the solar running into the pool today and the returns were pushing out warm water. The pool was 73 and the water coming in was 80. Still trial and error on the flow to get the optimal heat transfer but the pool ended up at 77 when I decided to turn the solar off. I'm still doing it manually for now. I may have to bump up my pump speed a little. I still have a couple of leaks to fix up too. Not enough time in the day...
 
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