Swap out solar heat exchanger tank-

[Tim Whistler]

Hey guys,
Anyone have any real-world experience changing out one of these tanks? Tank is rotting out and it's circulating glycol internally to heat the water. All valves appear to be working and in place on all four lines, I'm just a little concerned because I've never done one before. Is it as simple as just putting the new tank in reconnecting the lines and opening the valves back up? Or do I need to have glycol on hand and fill the system again or something?
Thanks,
Tim Whistler

Tim Whistler Plumbing
timwhistlerplumbing.com

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[breplum]

I've not done one myself but recall seeing hand pumps sold in the old days made for pumping back in.
Drain into a bunch of clean Rubbermaid trash cans using a transfer pump like for water heaters.
I don't have a solution for re-adding and doubt the WH transfer pump would work.

 

[Twowaxhack]

I've not done one myself but recall seeing hand pumps sold in the old days made for pumping back in.
Drain into a bunch of clean Rubbermaid trash cans using a transfer pump like for water heaters.
I don't have a solution for re-adding and doubt the WH transfer pump would work.

Good lord, how much solution does it hold ? I know it’s impossible to know for sure from here but “ a bunch of trash cans “ ? I guess it would be a function of how many collectors and how much piping is between the tank and the collector. Then of course the volume the exchanger holds

Solar never caught on here. Maybe that’s partly my fault ?

I’ve considered installing a system for my house but with our warm incoming water temps it would take forever to pay for itself.

If you had well water it would make better sense because of how cold well water is. Our city water incoming temps right now are near 80 degrees

 

[wpns]

If the valves are functional and you can turn off the glycol loop, then you shouldn't need to cope with a lot of 'lost' glycol, but there has to be a fill/purge process to get the air bubble out of the highest point in the system (probably at the panels). I'd imagine there's a valve or fitting at the top you loosen and then pump new solution in, though I suppose you could just take off a plug and fill it to overflowing at the highest point.

 

[breplum]

Because of tank rot, we would always recommend using stainless steel storage tanks...but when you look at those prices, with the cost of gas low (at least in the old days), it wasn't worth the investment as far as ROI. So only wealthy clients who don't care about ROI ever bother to keep their system at all. I've never been called to keep systems, only to demo.
Now as we slide away from fossil fuels, the trend is to get away from gas and use Solar PV for all home energy. Again, only for the wealthy at the moment.