Isolating solar heater?

lborne

0
Jun 29, 2009
468
Vero Beach, FL
I'm getting ready to buy all the plumbing I need to hook up my solar panels to my pool plumbing. The builder is installing a 3 way valve and a check valve just before the 3 way. I'll be adding an additional check valve on the return line from the solar panels. I've seen some schematics that show a ball valve in the straight pipes going to and coming from the solar panels to isolate the panels. Why is this necessary? If I have a check valve and the 3 way valve, I can bypass the solar panels, so I don't see the purpose of the ball valves.
 
I don't think that they are really needed and my system doesn't have them. The check valve and solar valve should provide enough isolation. They are more useful for systems which do not have a check valve on the return or no solar valve. Some installers put them in so they don't have to rely on the check/solar valve to be a 100% seal in case of a failure.
 
Some of the 3-ways are positive seal, no leakage past the closed part, and some have a hole in the gate part to allow the panels to drain without opening the valve. So in theory, if you have to cut your solar pipes after the 3-way and leave them open for repair, a small stream of water may escape from the valve.

Not really sure how much water would go out the hole, since it would travel the least resistence. Of course, if the solar input was the straight path and not the 90 degree turn, I would expect a heavy stream of water escaping.

If you have room for the ball valves I would just install them. Maybe $40 for both?
 
Thanks for the replies. Although I'm in south Florida, there are a few times a decade we do get below freezing, so making sure it can't accidently get water by a leaky 3 way valve is a good reason to have ball valves.

I was not concerned about saving money as much as reducing restrictions as much as possible. I was reading in another post about ball valves causing high restrictions when open.
 
I was reading in another post about ball valves causing high restrictions when open.
While true for most standard ball valves, you can buy full port ball valves. The easy way to tell is to open it and look through it. If the hole is the same size as the ID of the pipe it connects to then there won't be any restriction.
 
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