Installing Solar Diverter Valve

[stoteda]

I recently installed a complete Pentair System, EasyTouch controller, VS Pump, and IC40.

I am now ready to add the diverter valve to a roof mounted solar. I saw a picture in one of the posts that show a single diverter valve and a check valve, plus vacuum break at the top of the solar plumbing.
I want to have the system go on automatically when the solar is hot enough.
I assume I need a 3 way diverter with a pentair valve controller.


Is there a best practice for this?

 

[hwy17]

Do you have an existing solar system or is this all from scratch?

Florida Solar Design Group standard makes sense to me. Some use dual two way isolator valves but I agree with their logic that it's not necessary.

You can use a 3-way with a hole drilled in it, a 3-way and not completely close it for bypass mode, or ideally the specific Pentair 3-way solar isolator valve which has a tiny check valve in the blocker plate.

The main thing to wrap your head around is that the 3 way diverter needs to allow drain down from the supply pipe to the pool return when the pump is off.

Solar Pool Heating Valve Manifold Explained

Learn what all of the valves do in a solar pool heating system.

floridasolardesigngroup.com

 

[stoteda]

I was looking to keep things simple, and did not think I need the isolator valve, but I do have the check valve and vacuum break to allow the drain down.

Also, I plan to run the solar heating in line with the pump and before the sand filter. I've looked at the link to the Florida Design, and found it helpful, but it did not show the full system. I've attached an overall plumbing diagram I plan to use to guide my project.

The Pentair 3-way valve does not seem to be easily found in stock, so I've been looking online for this part. I was wondering if I can replace the diverter assembly from the Pentair 263028 with the diverter assembly from the Pentair 263047. If so, I can plumb everything this weekend and order the diverter later.

 

[hwy17]

You can definitely get simpler than the best practice. Mine is just an H with a two way valve in the bypass, the horizontal line. I rely on the built in check valve in my filter to prevent back flow.

The main problem with your plan there is unfiltered water to the panels. That is not advisable with any commercial panels, the channels can clog up with dirt and the pressure in the panel will be greatly increased.

I'm pretty sure you can replace the diverter in that three way with the solar drain down one, or you can just drill a hole in the diverter plate, or make sure to never fully close it.

 

[stoteda]

Once again TFP has saved our pool ; )

Great point on the unfiltered water, I will modify the design to move the solar intake to the filtered side, and out of caution, add a check valve below the diverter valve so the drain down flows out to the pool side and not back into the filter (which is what I was trying to avoid initially). So, this brings me to the original design you suggested without the one shutoff valve...thanks!

 

[stoteda]

Here is the modified plumbing diagram after taking your feedback into account. I also moved the intake to the Polaris pool sweeper to a point after the filter as well for the same reasons.

 

[Pool_Medic]

Only one check valve is needed on the solar return just before the 3 way valve.

 

[jerrymc]

I read this post and thought I'd add my 2 cents to the discussion. The valve I have is the Pentair 263026 and I thought I could just order the Pentair Solar Valve Diverter Assembly 270094 and replace the internal part and convert the valve into one that had the drain back feature. Well, it is possible but the shaft is too long so you have to cut off the bottom end to the same length. I see no reason for the difference in shaft length other than marketing wanting to sell the entire diverter valve to increase profit margins. I also tapered the bottom end to match the profile of the original. I'm not sure if that step was necessary as I just did it without checking. Hope this helps someone with a similar project.