Solar Check Valve

[woodsage]

I asked the solar installer why he installed the check valve on the supply instead of the return and I was told it's a new law/requirement that the check valve be installed this way; they used to install the check valve on the return but not anymore. This doesn't make sense to me.

Also, if a check valve is installed on the return, it will not prevent the water in the vertical pipe to the roof from emptying, correct? I'm not really sure the reason for the check valve on the return.

Should I add a check valve to the return? Should it be a spring or flapper check valve?

Thanx.

 

[JohnT]

You add a check valve coming from the filter to keep the water from the panels from running backwards through the filter when the pump shuts off while the solar valve is open.

The check valve at the outlet of the solar where it joins back in with the return line is to prevent water from entering the panels from the outlet when the solar is off.

 

[woodsage]

So, I already have a check valve on the supply side, do I need a check valve on the return side?

Do I use a spring or flapper check valve?

Should the return check valve be installed opposite the supply check valve (photo #1, #3) or can it be installed higher up?

 

[ping]

Mine has a spring check valve installed on the return side and it is below the ball valve, but you don't have the room there. Just install it above the ball valve on the return side.

 

[woodsage]

So, the return check valve should not be installed below the 3 way solar valve...

 

[ping]

So, the return check valve should not be installed below the 3 way solar valve...

I would put it above the 3 way solar valve so the water will not be able to flow up into the panels when the solar valve is in the off position.

If you install the check valve below the solar valve the water would still have two paths it can flow, up the solar return line to the solar panels, the wrong direction, and the other is out to the pool returns. You want to eliminate the water being able to flow in up the solar return line to the panels.