Solar Panel question

[Hookup]

Hi, first time post. I purchased a house last year with a 15K gallon in ground pool with solar panels installed on the roof. Last year I noticed what appeared to be sand at the bottom of the pool. I forgot to mention I have a Hayward sand filter. I was busy doing other things and never had a chance to troubleshoot the problem last year. This year when I opened up the pool I had the solar panels turned off for the first couple of weeks until I got the water balanced. At that time there was no sand in the pool. I turned the solar panels on a few weeks ago and the sand showed up again at the bottom of the pool. A few days ago I developed a leak in one of my solar panels so I turned off the solar panels and again no sand at the bottom of the pool. I already ordered the umbrella latteral pipe for my filter thinking that was the problem but now I am thinking that the problem is in the solar panel plumbing. There is no check valve on the solar inlet or outlet so when the solar is turned on and the pump shuts down all the water drains back through the pump and filter and I think this is how sand is entering into the pool. Does this sound possible? Should there be a check valve on both the inlet and outlet of the solar? If there is a check valve on both the inlet and outlet how will water drain from the solar panels when they are not in use. I'm afraid if I use check valves the water will get stagnet from sitting in the solar panels over the summer when they are not used. Any help is much appreciated, thx

 

[Bama Rambler]

You should have at least a check valve [s:324fcbc7]on[/s:324fcbc7] before the inlet to the panels. That prevents them from flowing back through the filter and pump when they're draining. They'll flow to the return and drain that way.

 

[mas985]

Welcome to the forum!

I think you are spot on. Every filter with elevated solar should have a check valve on the outlet side of the filter before the solar valve. Also, it is a good idea to have a check valve on the outlet side of the solar panels to prevent the panels from filling when the solar valve is in the off position.

However, I wouldn't put the check valve on the inlet side to the panels as this will not allow the panels to drain plus the outlet side could still drain through the filter.

 

[Bama Rambler]

That's what I meant, I just didn't say it well.

Edited post to fix.

 

[Weth]

You are right, the solar panels need to drain. But you are also correct in that it sounds like you are backwashing your sand filter into your pool.

You need to let the solar panel drain into the pool plumbing, but have a check valve between the filter and the return -- so it will be on the "main line" and not the outgoing to solar panel line. You will also want a check valve on the return line to prevent pressure from pushing water "backwards" through the solar panels. This would be on the return line of the solar plumbing.

---edit---
like everyone said. Lots of replies between me starting this and actually hitting the submit button!

 

[Hookup]

Awesome thanks for the help. Just so I am clear...I should have a check valve between the filter and pump and also on the outlet side of the solar panel plumbing right?

 

[Weth]

 

[Hookup]

Thanks for the diagram Weth but my pools plumbing is different (which might be part of my problem) Starting at the pool - the main drain and skimmer go to the filter first then to the pump. So basicaly if you switch the filter and pump around on your drawing then it would depict my setup with the exception of the check valves and ball valves. So would the check valve go between my filter and pump or between my pump and solar panels? Also I'm not sure what an Isolation ball valve is but I know there is none in my setup. I was wondering why people say they have to clean the basket out on there pump...I never have anything in my basket because the water is filtered first...makes sense now. Thx

 

[mas985]

The filter should always come after the pump not before so you need to fix that first. That will definitely cause you problems in the future especially when the filter gets dirty. Also, a sand filter with a backwash valve has much too much head loss for the suction side of pump. I'm surprised that you haven't had problems besides just the sand.

You want the system plumbed as is shown in the picture.

 

[Hookup]

I was afraid you were going to tell me that. Wonder why it was hooked up like that in the first place. AAARRRGGGGHHH