Started up a dormant Solar heating system...questions

[borjis]

Yesterday I decided was the day to do a test of my solar heating system.

Previous owner of the home had never used it. The automation control panel
is dead and the sensors disconnected.

So with the pump off, I manually opened up the send & return ball valves (photo below)
then turned the diverter to the solar panels and turned on the pump.

In about 1 minute I could hear the water returning from the panels
and the temp gauges on the plumbing read 55 degrees outgoing and 65 degrees incoming... YAY!
It dropped down to about 58 after a few minutes.

Great, but hurry and get on the roof to check for any leaks i think and low and behold there
is, but to my surprise only 1. (photo below)

these are solar industries hard plastic type panels and I have found a tutorial for cutting
away a small section at the hole (looked melted as if a spent firework landed on it lol) then
inserting some 1/4" threaded nylon bolts with the heads cut off and covered with liquid nails
to seal them in.

My main question is this:

This system had automation and the ball valves to and from solar obviously have to be open
during operation. When I shut down the pump (I could hear the water drain down fast by the way)
then waited until no more water was heard draining, I left the ball valves open and only changed
the diverter then turned pump back on.

I could hear water coming up backwards from the solar return (makes sense) but will the water
only be going up a little bit? surely it won't go all the way through the solar panels backwards right?

The ball valves have to be open if automation is controlling the diverter. I just kind of find it odd
they didn't use a check valve instead to keep it from flowing backward.

The panel system was installed in 1993.

thanks

 

[JasonLion]

Normally there is a check valve that prevents the panels from filling up backwards when the pump is off. I don't see one in your photo, though I can't see the entire return pipe.

If there isn't a check valve on the solar return line, I recommend adding one. It isn't the end of the world without the check valve, but it does cause more wear on the panels without one.

 

[borjis]

That's what I was guessing.

It seems like, with the ball valves open, but bypassing the panels, the return jet pressure would be less
since the water is literally climbing backwards up the panel return on it's way to the main return jets.

Will the water basically be raising almost to roof level then?, while outputting to the return jets (in panel bypass mode)

 

[JasonLion]

The height the water will reach depends on a number of details of your plumbing. It could easily be as high as filling the panels completely, though it could likewise easily be lower than that.

 

[borjis]

thanks Jason.

I'm very excited to be using these panels to heat the water.