Jandy Check Valve not blocking all reverse flow

[Vandergraff]

I have a new Jandy Check Valve installed to stop backflow into my solar panels when the solar isn't running. It is on the return line from the solar panels.

I see some reverse flow coming from the check valve - not a lot but definitely some. Is this normal or should the check valve stop all reverse flow?

I don't want any backflow into the panels during winter.

I have cleaned it out to make sure there is no debris keeping the valve open.

This seems to be the valve https://www.jandy.com/en/products/valves/check

 

[Jimrahbe]

v,

I am not a solar expert, but all the solar systems I have seen have a bypass system that isolates the solar panels in the winter..

I would have assumed that your new check valve would prevent all reverse water flow, but not sure what impact a little reverse flow would have...

If you can provide us with a picture of the valves in your solar set up, I'm sure we can get one of our solar experts to chime in...

Thanks for posting,

Jim R.

 

[cfherrman]

Is the up portion of the valve installed up? Shut the line off and pop the cap and check the rubber.

No check valves should never be trusted to eliminate all flow

 

[Vandergraff]

OK - it looks like I was wrong about the make of the check valve - loos like it is FLOWVIS® FLOW METER with check valve https://www.h2flow.net/flowvis-flow-meter/

Yes it is installed the correct way round.

In addition to seeing some back flow through the check valve the flow meter is also failing to register flow rate when water returning from the solar panels. I know there should be sufficient flow as another flow meter shows 20 - 25 GPS going to the panels which must also be coming back via the return....

cfherrman - when you say no check valve should be ever trusted to eliminate all flow what would you recommend to stop water flowing back to the panels when solar not running?

 

[cfherrman]

The only option is a quality serviceable check valve, then when it total un use, a valve.

 

[Vandergraff]

The only option is a quality serviceable check valve, then when it total un use, a valve.

So you don't think the FLOWVIS® FLOW METER with check valve is a quality check valve?

Any recommendations of what is a quality check valve.

Yes we do also have a valve (Jandy 3 way valve) which I have switched to off for the winter - but even with this off there a small flow coming back towards the panels. Confirmed by opening a manual drain valve on the return from the panels. My solar installer wants that open duing the winter.

 

[Jimrahbe]

V,

Watch this video and tell us if this is how your system is plumbed.. It does not sound like it to me..

Powerstrip Solar Pool Heater Operation and Plumbing Guide - YouTube

Thanks,

Jim R.

 

[cfherrman]

So you don't think the FLOWVIS® FLOW METER with check valve is a quality check valve?

Any recommendations of what is a quality check valve.

Yes we do also have a valve (Jandy 3 way valve) which I have switched to off for the winter - but even with this off there a small flow coming back towards the panels. Confirmed by opening a manual drain valve on the return from the panels. My solar installer wants that open duing the winter.

I have no idea, if it is serviceable, then it is probably good enough.

 

[PoolGate]

I thought when solar panels were not in use the water was supposed to drain out of them.

 

[Vandergraff]

V,

Watch this video and tell us if this is how your system is plumbed.. It does not sound like it to me..

Powerstrip Solar Pool Heater Operation and Plumbing Guide - YouTube

Thanks,

Jim R.

I don't have the 2 ball valve - but rest is basically the same.

Edit - also the ball valves may help in winter but won't help in summer when solar on but water has reached desired temperature. In this case water might still flow back through the check valve and sit up in the panels likely causing severe damage to the panels with super heated water.

 

[Vandergraff]

I thought when solar panels were not in use the water was supposed to drain out of them.

It does - but if the check valve is letting water flow back water could be sent back up to panels.

If I leave the winter drain plugs out (which my solar installer wants me to do) water would drain out the drain plugs.

If I leave the drain plugs in then there is slight chance wayer could get pumped up to the panels (I don't think there is a enough pressure) and be a freeze issue.

Also in summer water could get sent back up to the panels and if sitting in the panels overheat with bad result.

 

[Jimrahbe]

I don't have the 2 ball valve - but rest is basically the same.

I guess my point was that the ball valves all you to isolate the solar in the winter...

Jim R.