Questions about Solar plumbing

[atttech-2]

So I started to do some research on plumbing for solar and some of the schematics I have seen get quiet complicated. My PB put 2 dedicated returns in the floor of the pool he called DPs as part of the base price of the pool. Right now they share return flow with skimmer returns via a 3-way but that is just so I can keep sanitized water flowing through them a bit. I did some searching but did not find any thing referencing DPs and only found 1 diagram, shown below that I modified slightly, that showed solar with a dedicated return separate from the skimmer returns.

My questions are these.

1.) on the attached diagram wouldn't I want a 2 port valve on the line where I but the black circle to somewhat reduce the flow to the normal retuns so that water is forced up to the panels? I am thinking I would not shut it 100% just enough to increase the pressure so I would not have to run the pump full out to supply enough flow to get the water to rise to the panels.

2.) Do I need the 2 port valve before the automated 3-way valve, that is just there to isolate the panels when not in use correct? If that is the case can't I just use the automated valve to isolate the system?

3.) Why the 3-way automated valve with 1 leg caped? I would assume it was just modified off of another diagram and a 2-port would be more appropriate for this build or am I missing something?

4.) Ball valves vs. Jandy 2 ports. I know I have to have the Jandy for the automated valve but should I also use them instead of ball valves? Are the ball valves OK for low use situations or should I use Jandys? I am not opposed to the extra cost as long as there is a good reason for it.

Any and all suggestions are welcome, I am not pulling the trigger on the actual panels till next season but I may do the plumbing at the pad and up the side of the house in the next few months.

 

[mas985]

I would just put a solar valve where the Tee is now to the left of the black circle and eliminate the green three way that no longer has a three way port. I don't think you will want to run both solar and the normal returns. Otherwise, you will need to run at much higher RPM (and energy) to supply both. Not really necessary either if you plan on using a solar cover which is always a good idea.

However, where do you plan on injecting the chlorine and acid you have now?

 

[jblizzle]

I am getting confused by your terminology. You keep saying skimmer return, but we usually refer to returns as putting water back in the pool.
The DP sound just like floor drain SUCTION lines that tie into your skimmer SUCTION line.
Unless the DP are truly return lines putting water back into the pool, in which case they have nothing to do with the SKIMMER.

 

[Isaac-1]

It seems that drawing is for dedicated hot solar returns in the pool floor, not exactly a common installation, but yes I think you would want a variable possibly ball valve where the black circle is, or just plumb the cold return to the right side of the 3 way valve where the stub is. The problem with the cheap ball valves is they swell and stick, but as long as you are never going to touch it again you can probably get away with it. The big thing you want to do is minimize return restriction, when I installed my current solar panels I had to go back and replace the eyeball fittings with one size larger to reduce back pressure at the panels. Also given that you have a variable speed pump you probably don't need that bypass bridge as you should never need to have panel bypass flow to reduce back pressure, instead you can just lower the pump speed a little. On topic 3 I agree it looks like h2ot sun modified the diagram for this special bottom return feed install. If you opt for ball valves, at least get the Hayward ones that can be serviced.

 

[atttech-2]

I would just put a solar valve where the Tee is now to the left of the black circle and eliminate the green three way that no longer has a three way port. I don't think you will want to run both solar and the normal returns. Otherwise, you will need to run at much higher RPM (and energy) to supply both. Not really necessary either if you plan on using a solar cover which is always a good idea.

However, where do you plan on injecting the chlorine and acid you have now?

I think the 3-way at the first T after the back flow sounds like the way to go. I would move the acid injection to the 4 wall returns after the supply for the booster pump (basicly last thing before the pipe goes under ground) chlorine I was thinking of possibly moving to the 2" line that feeds the polaris on the output of the booster, I have the high presure check valve and would be using a proper T with a threaded port so I don't think there will be a presure problem. That would put all my chemical injections on a completely separate return from the solar with the added benefit of being separate from each other, not that I run them near the same time but would be extra insurance just incase. If someone thinks feeding 100% of the chlornaited water to the polaris coudl be a problem there is room for the chlorine to go just after the solar wich would feed it to the 4 wall returns and polaris.

 

[atttech-2]

Unless the DP are truly return lines putting water back into the pool, in which case they have nothing to do with the SKIMMER.

They are truly returns in the floor of the pool they have a flat cover instead of an eyeball and are fed from a 3-way from the filter that feeds them on one side and the wall returns on the other (what I was calling skimmer return I think "wall return" is a better description). When active they put water in the pool but do nothing for skimming.

 

[pooldv]

Take a look at the plumbing in my build thread, link in sig. The left pipe goes up to solar and the right pipe comes back from solar. The lower left pipe is coming from the filter and the lower right pipe goes to the SWG and to the pool.

More here, Solar Pool Heater Technology, learn how solar pool heaters work

 

[atttech-2]

Thanks for the link Pooldv. Ok all I have done an edit of the diagram, I used the 3-way as Mas985 and Issac-1 suggested, I also moved the check valve to the output to the solar since it seems I don't need it on all the plumbing, just the solar and perhaps it will last longer and be less restrictive to the plumbing when not inuse. So now the questions are, does moving the check valve seem sound, and do I need the connecting pipe and valve between the hot and cold sides? I am thinking it is there to reduce pressure up to the panels if needed but the 3-way being adjustable and having a VS pump I have 2 options to control the pressure so don't think I will need it.

Oh one last question should I use jandy flapper check valve or a spring style?

 

[Isaac-1]

The bridge piece with the valve does provide a path for the standing water in the panels to drain down to on the cold feed side, this is essentially what I have on my solar install made from 1/2 inch PVC and a cut off valve that is turned down to just allowing a trickle of water through. As to the check valve I would move it back to the original location, with separate solar return you don't need a check valve on the hot return side since there will be no added backpressure from a shared return system. The Check valve needs to be located after the filter so that if there is a power failure or pump shut down with the solar valve in the solar position the water will not drain back through the filter, and in essence backwash your filter into your pump basket and back to the skimmer. As to type of check valve I would use a Jandy flapper type.

Ike

p.s. You could possibly eliminate the bridge piece if you automation system is set up to turn the pump off while the valve transitions from solar on to solar off, and if the valve is configured to allow flow to drain through to the pool cold return as the actuator turns. These actuators take about 20 seconds are so to cycle a valve, which should be long enough for the water column to drain through. The easier way is probably to do what I did though and build a 1/2 or 3/4 inch PVC bridge with a common gate valve and let it trickle. Here is a picture of mine, it was built with parts on hand as the nearest hardware store is 20 miles away.

Equipment is indoors behind the wall