Will a check valve prevent losing prime with solar panels engaged?

[borjis]

I've repaired two leaking panels with plugs and heated the pool water 6 degrees a few times.
As a result I was able to swim for the first time this season last saturday.

pretty cool seeing that work.

But I've noticed the solar installation (from 1993) lacks a check valve between the filter
and diverter to solar or direct pool returns and also no check valve just before the solar (heated water coming back)
plumbing goes back to the returns.

Right now the system is all manual as the control panel was dead. I also have 1 orange ball
valve after the diverter to solar and another one right before the solar plumbing goes to
the return jets.

So when I open those up and divert from return jets, to solar then it gets going....much later in the day
when the pump is turned off I hear the panels drain. If I leave it like that overnight the pump basket
empties. Also after the panels drain, I hear gurgling in my filter and some dirty water from the filter back
flows a little to my skimmer which is odd because I do have a check valve between the pump and filter.



If I get check valves installed in the two places in the plumbing for solar will that prevent it from
losing prime in the pump basket with the diverter on solar and ball valves open?

I had hoped it would work this way so that when the pump automatically turns on at noon
it is heating the water on sunny days when I'm at work.

I tried letting it do that once on a sunday and the pump basket could never get fully
pressurized and I had vortexing at the skimmer even though the pool is fully filled to the line.
I sure as heck wouldn't want it doing that while I'm away.

my workaround for now is to manually turn off the pump when the sun stops heating the panels
and once the panels drain, I close the ball valves and move the diverter back to return jets position.

 

[n240sxguy]

Usually there is a check valve on the line going to the panels, but not on the way back to the pool that I have seen. Putting one on the line to the panels would prevent them from draining back through the filter, and only allow them to drain to the pool returns. It is odd that it back flows through the current check valve. Is it one of the clear top ones where you can check to see if there is an obstruction preventing it from closing?


Sent from my iPhone using Tapatalk

 

[borjis]

I think the reason for having a check valve on the solar return as well as the incoming is to prevent
the panels from filling up backwards when the ball valves are open during summer operation with automation
engaging / disengaging them. The one time I left the ball valves open and only used the diverter to turn
the panels off, I could hear water going through the pipe in reverse trying to equilize itself back into the panels.

The 1 check valve I have between pump and filter is not see through unfortunately. I bet it is stuck, there's
no other explanation to why its backing into the skimmer when I shut it off.

 

[n240sxguy]

I can see how it could be used either way. I assume the necessity of the check valve on the return would be determined by where the vrv is mounted. If you bypass the solar, without a check valve on the return, some water would push back up that pipe, but most of it would be going to the pool since it is lower pressure. If your vrv is at the top of the solar panels, that shouldn't be a problem. If it is closer to the ground, the water pushing back up that line probably wouldn't have enough pressure to seat it, and it would leak.


Sent from my iPhone using Tapatalk

 

[borjis]

The relief valve is mounted at the lower end of the last panel on the roof.

 

[jblizzle]

borjis, you are correct on where there should be check valves.

 

[dschlic1]

My system has just one check valve, on the discharge side of the filter. The pump remains primed all of the time.

 

[jblizzle]

The 2nd check valve on the solar return is so that the panels are not filled/pressurize backward when solar is off. Nothing to do with the pump losing prime.

 

[borjis]

thanks for the replies.

I only lose prime when the ball valves are open, regardless of where the diverter is positioned.

would the check valves prevent loss of prime when the diverter is going to solar? do they seal up when no water is flowing?

or merely prevent back flowing?

 

[jblizzle]

I never lose prime whether solar is on or off. The check valve after the filter should prevent the solar from draining back through the filter and pump. Since the filter can not drain, prime is not lost.

 

[pooldv]

There is a pic of my solar valve and check valves in my build pic in my sig. Left side goes up to panels, right side is return from panels. I never lose prime either.

 

[borjis]

I was hoping that was the case, thanks for letting me know.

Can't figure why the solar installer did it without check valves but that was 20 years ago.