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We installed two 30 tube panels on our roof in 2006. They made 100% of our domestic hot water and contributed a tad to our in-floor heating. We recently ordered 3 more panels to add to the existing 2 because we wish to heat our house even more using solar.
In order to add on, we had to remove the existing tubes so we could drain the system. While we were removing the tubes we found 23 of the 60 tubes had gone bad. Upon inspection, we found the slim copper tube inside the glass had expanded and split at the bottom. The copper looks like a bloated puffer fish! This released the water inside the copper and made the tubes useless in conducting heat. We live in northern Wisconsin and it's not uncommon to have -20 degrees for weeks on end. We believe the copper inside the evacuated tube froze and burst. We don't know if the vacuum had been lost, and thus lead to freezing? Each tube seems to be completely in tact, no glass is cracked or broken. Even the seal between the glass and the metal looks fine. Can the liquid inside the copper freeze even with a vacuum? And why did 23 of them go bad and not the full 60?
My husband believes the vacuum still exists in those bad tubes, but the copper still got cold enough to burst. He believes this because there is a stretch of coiled metal going from the glass to the big copper head at the top of each tube. It's the skinny neck part. This neck part isn't insulated. This neck is exposed to that cold air on frigid January nights. Could that cold be entering the neck and traveling down the copper tube and freezing it? He believes this is what happened. He believes the 23 unfortunate tubes were the ones that slipped a bit past the manifold and really got exposed to the cold air. They slipped a bit when we cleaned the snow off them. When I slipped a bit, I mean like 1/4 inch. There's nothing but a strip of plastic on the bottom of the manifold protecting that neck, and the tubes could easily slip a bit beyond that plastic strip. The new Kingspan tubes have a clip to hold them into the manifold so they can't slip. But the necks still aren't insulated. Don't they think cold can penetrate that uninsulated strip of plastic?
To add insult to injury, Thermomax was bought by Kingspan Solar in 2007, and all tubes sold before that aren't covered under warranty. So we lost our warranty. But since we already have 37 good tubes, racks, and a system in place we will be purchasing 23 more tubes from Kingspan. But we are going to insulate those wire necks ourselves to make sure they don't freeze.
Also, we never would have known these tubes were bad if we hadn't ordered more panels. We don't annually go up on our roof to check tubes after winter has passed. We never thought it was something we had to do. Kingspan says they've not have any complaints on solar sold to northern climates. But do those panels get checked annually? Maybe they have bad panels and don't know it.
Looking at our solar data, it seems the tubes went bad after the first year because our production really dropped. We thought it was just a really sunny first year and never thought about it more than that. If we would have done an annual check up, we could have maybe caught it soon enough to be under warranty before Thermomax went belly up. If you wish to install evacuated tubes in a cold climate, be prepared to annually check your tubes.
In order to add on, we had to remove the existing tubes so we could drain the system. While we were removing the tubes we found 23 of the 60 tubes had gone bad. Upon inspection, we found the slim copper tube inside the glass had expanded and split at the bottom. The copper looks like a bloated puffer fish! This released the water inside the copper and made the tubes useless in conducting heat. We live in northern Wisconsin and it's not uncommon to have -20 degrees for weeks on end. We believe the copper inside the evacuated tube froze and burst. We don't know if the vacuum had been lost, and thus lead to freezing? Each tube seems to be completely in tact, no glass is cracked or broken. Even the seal between the glass and the metal looks fine. Can the liquid inside the copper freeze even with a vacuum? And why did 23 of them go bad and not the full 60?
My husband believes the vacuum still exists in those bad tubes, but the copper still got cold enough to burst. He believes this because there is a stretch of coiled metal going from the glass to the big copper head at the top of each tube. It's the skinny neck part. This neck part isn't insulated. This neck is exposed to that cold air on frigid January nights. Could that cold be entering the neck and traveling down the copper tube and freezing it? He believes this is what happened. He believes the 23 unfortunate tubes were the ones that slipped a bit past the manifold and really got exposed to the cold air. They slipped a bit when we cleaned the snow off them. When I slipped a bit, I mean like 1/4 inch. There's nothing but a strip of plastic on the bottom of the manifold protecting that neck, and the tubes could easily slip a bit beyond that plastic strip. The new Kingspan tubes have a clip to hold them into the manifold so they can't slip. But the necks still aren't insulated. Don't they think cold can penetrate that uninsulated strip of plastic?
To add insult to injury, Thermomax was bought by Kingspan Solar in 2007, and all tubes sold before that aren't covered under warranty. So we lost our warranty. But since we already have 37 good tubes, racks, and a system in place we will be purchasing 23 more tubes from Kingspan. But we are going to insulate those wire necks ourselves to make sure they don't freeze.
Also, we never would have known these tubes were bad if we hadn't ordered more panels. We don't annually go up on our roof to check tubes after winter has passed. We never thought it was something we had to do. Kingspan says they've not have any complaints on solar sold to northern climates. But do those panels get checked annually? Maybe they have bad panels and don't know it.
Looking at our solar data, it seems the tubes went bad after the first year because our production really dropped. We thought it was just a really sunny first year and never thought about it more than that. If we would have done an annual check up, we could have maybe caught it soon enough to be under warranty before Thermomax went belly up. If you wish to install evacuated tubes in a cold climate, be prepared to annually check your tubes.
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