Refurbishing old solar hot water panels

Daox · 05-06-20, 12:46 PM

Its been quite some time, but years ago I got 10 solar hot water panels from BenNelson. They had been sitting for quite some time with the glass panels off and need some work. I started the project, but stopped years ago. Now, I am coming back to it and looking to finish it this summer! Thanks Menaus2 for some motivational work on your own solar setup!

Last I left them I had pressure tested 3 of the panels. I know at least one of the panels has a seam split on one of the risers that will need to be repaired.

So, yesterday I took a look at the remaining 7 panels. I cleaned them out quickly and inspected and disassembled the few that hadn't been disassembled. They'll need to be pressure tested.

My current question for you guys is how would you connect these solar panels? The guys that took down the panels just used a sawzall and lopped off the header pipes so they barely extend beyond the sheet aluminum case. I had planned on using PEX tubing between them. This seemed like a nice idea because it was simple, but I'm a bit worried about overheating the PEX and that causing leaks. Do you guys have any suggestions?

menaus2 · 05-11-20, 09:16 AM

Glad I was able to inspire you haha. Looks like recycling & reuse at it's best, what a great project to have laying around! Seems to me soldering on copper pipe would be the most straightforward option...

Daox · 05-12-20, 05:35 PM

Alright, I need some recommendations on how to mount the glass to the cases. These panels originally came with glass that had a big rubber gasket around them, and there were little brackets that screwed on. IMO this is a horrible idea. Not only that, but the rubber gaskets are shot due to their age. So, I am looking for another solution.

I seem to remember I had the suggestion years ago from Randen (I think) about using urethane glue? However, I can't seem to find that post.

What would you guys suggest to mount the glass on the solar panel cases (aluminum)?

Daox · 05-12-20, 05:38 PM

Right now, I'm thinking something like this would probably work out pretty well.

3M Auto Glass Urethane Windshield Adhesive, 08693, 10.5 fl oz Cartridge

menaus2 · 05-12-20, 11:55 PM

Could you create new gaskets with silicone caulk? Maybe by making a mold? I'm not sure how well silicone would hold up directy in the elements. You might look into Lexel adhesive. That stuff is like liquid duct tape, except better. Not sure how it holds up to high temperatures though.

roger1959s · 06-13-20, 06:57 AM

My current question for you guys is how would you connect these solar panels? The guys that took down the panels just used a sawzall and lopped off the header pipes so they barely extend beyond the sheet aluminum case. I had planned on using PEX tubing between them. This seemed like a nice idea because it was simple, but I'm a bit worried about overheating the PEX and that causing leaks. Do you guys have any suggestions?

[/QUOTE]

They sell metal connectors for gas water heaters that would work but would cost a lot for that many connections.I think to code a gas water heater connection has to be 18 inches long.Then the PEX would hook to it.What i don't know is if they would have to that long when hooking up your solar panels.

roger1959s · 06-13-20, 07:11 AM

A few years back i fixed a leaking "T" top on my wife's Trans Am by putting a thin layer of black RTV on the "T" top gasket and Vaseline on the "T" top glass and latching the tops back in place. The next morning took the tops back off and cleaned the Vaseline off the glass and the by then dry gaskets.Lasted years on the old '79 TA.

jeff5may · 06-14-20, 12:16 AM

Ok so there are a few ways you can go about refurbishing the panels. Your ultimate decision will be determined by the purpose and ease of maintenance of the system.

Choice number one: never service again, system will run perfect like magic, permanently. This entails using the window weld butyl glue and soldering copper pipe between everything. Either run a drain back setup or use glycol and a steam catcher. Goes together once, maybe top off or change glycol mixture not often.

Choice number two: serviceable in case things happen. This entails using rubber heater hose and hose clamps to connect with your sawed off ends and barb fittings to whatever pipe suits your needs. If you're running the panels in parallel, I would use rigid pipe for headers. If you're not making steam, you shouldn't need to worry about high pressure or temperature. Use weatherstrip tape for the window seals: single sticky side if the windows hold together with fasteners and strips, double sticky if the tape holds them together.

Somewhere in between: shark bite couplers are magical, until they're not. Easy peasy put together, not cheap but worth it in time savings. If it doesn't leak when you put it together, it won't leak for a long time. Things have to be clean and smooth and round and such.

Daox · 10-29-20, 01:16 PM

Alright, my wife and I have been working on these panels the past couple days. I brought the panels inside as its been in the mid 30F to mid 40s lately. Its so much nicer to work indoors with glues and sealants.

So, all the panels used to have these two holes in opposite corners to connect the old rubber couplers. I decided to cut little aluminum plates and JB weld them on to the panels.

I also noticed that the panels have small cutouts on each end. I'm not sure why these aren't sealed, but they aren't. Maybe one of you other solar water panel guys can explain that.

Daox · 11-02-20, 09:05 AM

So, I have a smallish updated.

First, I've finished sweating PEX fittings on the rest of the panel inserts, yay.

Second, I've been pressure testing the panels. This isn't the fastest process, but IMO its necessary before putting them up in the air and finding out there is a leak!

To do this, I crimp plugged PEX lines to each corner. One has a air fitting with a ball valve and pressure gauge. I fill it up and let it sit for a while.

This part is all easy. The hardest part is actually removing the PEX lines. Once they're crimped on there they are very hard to pull off, even after cutting the metal crimps off. If anyone has any tips on how to remove PEX lines from then fittings it sure would be nice.

05-06-20, 12:46 PM	#1
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Refurbishing old solar hot water panels Its been quite some time, but years ago I got 10 solar hot water panels from BenNelson. They had been sitting for quite some time with the glass panels off and need some work. I started the project, but stopped years ago. Now, I am coming back to it and looking to finish it this summer! Thanks Menaus2 for some motivational work on your own solar setup! Last I left them I had pressure tested 3 of the panels. I know at least one of the panels has a seam split on one of the risers that will need to be repaired. So, yesterday I took a look at the remaining 7 panels. I cleaned them out quickly and inspected and disassembled the few that hadn't been disassembled. They'll need to be pressure tested. My current question for you guys is how would you connect these solar panels? The guys that took down the panels just used a sawzall and lopped off the header pipes so they barely extend beyond the sheet aluminum case. I had planned on using PEX tubing between them. This seemed like a nice idea because it was simple, but I'm a bit worried about overheating the PEX and that causing leaks. Do you guys have any suggestions? Attached Thumbnails __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

05-12-20, 05:35 PM	#3
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Alright, I need some recommendations on how to mount the glass to the cases. These panels originally came with glass that had a big rubber gasket around them, and there were little brackets that screwed on. IMO this is a horrible idea. Not only that, but the rubber gaskets are shot due to their age. So, I am looking for another solution. I seem to remember I had the suggestion years ago from Randen (I think) about using urethane glue? However, I can't seem to find that post. What would you guys suggest to mount the glass on the solar panel cases (aluminum)? __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

05-12-20, 05:38 PM	#4
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Right now, I'm thinking something like this would probably work out pretty well. 3M Auto Glass Urethane Windshield Adhesive, 08693, 10.5 fl oz Cartridge Attached Thumbnails __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

06-13-20, 07:11 AM	#7
roger1959s Lurking Renovator Join Date: Aug 2011 Location: south carolina Posts: 2 Thanks: 0 Thanked 2 Times in 2 Posts	A few years back i fixed a leaking "T" top on my wife's Trans Am by putting a thin layer of black RTV on the "T" top gasket and Vaseline on the "T" top glass and latching the tops back in place. The next morning took the tops back off and cleaned the Vaseline off the glass and the by then dry gaskets.Lasted years on the old '79 TA. Last edited by roger1959s; 06-13-20 at 07:12 AM.. Reason: added to

10-29-20, 01:16 PM	#9
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Alright, my wife and I have been working on these panels the past couple days. I brought the panels inside as its been in the mid 30F to mid 40s lately. Its so much nicer to work indoors with glues and sealants. So, all the panels used to have these two holes in opposite corners to connect the old rubber couplers. I decided to cut little aluminum plates and JB weld them on to the panels. I also noticed that the panels have small cutouts on each end. I'm not sure why these aren't sealed, but they aren't. Maybe one of you other solar water panel guys can explain that. Attached Thumbnails __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

05-11-20, 09:16 AM	#2
menaus2 Apprentice EcoRenovator Join Date: Feb 2011 Location: Driftless Region, North America, Earth, Solar System, Orion Arm, Milky Way Galaxy,Virgo Supercluster Posts: 116 Thanks: 13 Thanked 35 Times in 25 Posts	Glad I was able to inspire you haha. Looks like recycling & reuse at it's best, what a great project to have laying around! Seems to me soldering on copper pipe would be the most straightforward option...

05-12-20, 11:55 PM	#5
menaus2 Apprentice EcoRenovator Join Date: Feb 2011 Location: Driftless Region, North America, Earth, Solar System, Orion Arm, Milky Way Galaxy,Virgo Supercluster Posts: 116 Thanks: 13 Thanked 35 Times in 25 Posts	Could you create new gaskets with silicone caulk? Maybe by making a mold? I'm not sure how well silicone would hold up directy in the elements. You might look into Lexel adhesive. That stuff is like liquid duct tape, except better. Not sure how it holds up to high temperatures though.

06-13-20, 06:57 AM	#6
roger1959s Lurking Renovator Join Date: Aug 2011 Location: south carolina Posts: 2 Thanks: 0 Thanked 2 Times in 2 Posts	My current question for you guys is how would you connect these solar panels? The guys that took down the panels just used a sawzall and lopped off the header pipes so they barely extend beyond the sheet aluminum case. I had planned on using PEX tubing between them. This seemed like a nice idea because it was simple, but I'm a bit worried about overheating the PEX and that causing leaks. Do you guys have any suggestions? [/QUOTE] They sell metal connectors for gas water heaters that would work but would cost a lot for that many connections.I think to code a gas water heater connection has to be 18 inches long.Then the PEX would hook to it.What i don't know is if they would have to that long when hooking up your solar panels.

06-14-20, 12:16 AM	#8
jeff5may Supreme EcoRenovator Join Date: Jan 2010 Location: elizabethtown, ky, USA Posts: 2,431 Thanks: 431 Thanked 619 Times in 517 Posts	Ok so there are a few ways you can go about refurbishing the panels. Your ultimate decision will be determined by the purpose and ease of maintenance of the system. Choice number one: never service again, system will run perfect like magic, permanently. This entails using the window weld butyl glue and soldering copper pipe between everything. Either run a drain back setup or use glycol and a steam catcher. Goes together once, maybe top off or change glycol mixture not often. Choice number two: serviceable in case things happen. This entails using rubber heater hose and hose clamps to connect with your sawed off ends and barb fittings to whatever pipe suits your needs. If you're running the panels in parallel, I would use rigid pipe for headers. If you're not making steam, you shouldn't need to worry about high pressure or temperature. Use weatherstrip tape for the window seals: single sticky side if the windows hold together with fasteners and strips, double sticky if the tape holds them together. Somewhere in between: shark bite couplers are magical, until they're not. Easy peasy put together, not cheap but worth it in time savings. If it doesn't leak when you put it together, it won't leak for a long time. Things have to be clean and smooth and round and such.

11-02-20, 09:05 AM	#10
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	So, I have a smallish updated. First, I've finished sweating PEX fittings on the rest of the panel inserts, yay. Second, I've been pressure testing the panels. This isn't the fastest process, but IMO its necessary before putting them up in the air and finding out there is a leak! To do this, I crimp plugged PEX lines to each corner. One has a air fitting with a ball valve and pressure gauge. I fill it up and let it sit for a while. This part is all easy. The hardest part is actually removing the PEX lines. Once they're crimped on there they are very hard to pull off, even after cutting the metal crimps off. If anyone has any tips on how to remove PEX lines from then fittings it sure would be nice. Attached Thumbnails __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.