# Solar thermal pool rehabilitation



## Protech (Sep 22, 2008)

I have this customer that keeps calling me out to fix breaks on his solar pool heating system that was installed by another contractor (a Fafco system). I've told the guy several times that they screwed it up royally and it needs to be redone. He keeps having me just patch the return line every time it cracks/bursts. I finally told him I'm not going to come back anymore and participate in this foolishness. I will however give him a great deal on "de-hacking" the system somewhat (he's used me several times, so I figure I'll work with him).

The biggest problems are that the roof sensor is not on the same roof face as the solar array and that the array is not piped with a reverse return configuration. Because the sensor is on the east face of the roof and the array is on the south face, the controller is kicking the system on and off at the wrong times. Because the array is hooked up with both the supply and return on the same side, the first collector gets most of the flow and each one after that gets less and less. That hurts your output big time. 

Also, because of how the diverter valve and check valves are arranged, the system does not drain when the pump is running and it still circulates a tiny bit even when the pool is heated to the desired temperature. This means the water in the collectors and the return pipe is being over heated. Because the water in the return pipe is super hot (150 degrees at times) and is pressurized fro the pump, the pvc pipe and fittings keep failing. They are not designed for those temps under pressure.

The solution is to run the return is sch. 80 cpvc and move the sensor to the south face.


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## Protech (Sep 22, 2008)

You can see just how soft the pvc gets on the hot roof. This was in the morning and it's not even summer yet.


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## Titan Plumbing (Oct 8, 2009)

In the last pic it looks like he in enjoying your company anyway.


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## Protech (Sep 22, 2008)

If you look at the next door neighbors system, you can see that it's piped correctly (it's in a very zig zag and ugly manner, but it is mechanically correct).

That is also the same equipment manufacturer I use though I did not install that system.


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## Protech (Sep 22, 2008)

I a previous discussion with "Camillo" and "saveonsolar", they stated that skid plates were not needed and that the collectors and pipes did not move since they were strapped down. I disagree and I would like to submit these photos to support my case. You can clearly see where the return pipe was abraded the roof deck from thermal cycling.


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## Protech (Sep 22, 2008)

The new sch.80 cpvc return pipe going in. NO SKID PLATES were used due to the homeowner being a cheep A**.


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## Protech (Sep 22, 2008)

more pics


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## Tankless (Jun 12, 2008)

This is something I know a thing or two about!!

Air temp sensor doesn't need to be mounted right on the collectors ( however that is the correct way to do it) It just needs to get the same sun. The return ....dude, that's just funny how the other guy did it. They gotta drain down. Maybe the original installer sold the HO on no bubbles when the system heats up. 

It's hard to tell from the pics, but why is the supply and the return off the same primary collector? The return should be on the opposite end, no?

Is there a way you can tell how ballanced the collector flow is?
Is it on a seperate booster pump or an actuated valve?


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## Protech (Sep 22, 2008)

responses in red



Tankless said:


> This is something I know a thing or two about!!
> 
> Air temp sensor doesn't need to be mounted right on the collectors ( however that is the correct way to do it) It just needs to get the same sun. The return ....dude, that's just funny how the other guy did it. They gotta drain down. Maybe the original installer sold the HO on no bubbles when the system heats up.
> 
> ...


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## ckoch407 (Sep 30, 2009)

Thats a shame. There are some real butchers out there.


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## 2010_Frontier (Mar 18, 2010)

Are you guys required to use purple primer or can you use the clear primer? Years ago it was code to use the purple stuff so the inspector could see you primed the pipe....


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