used solar hot water collectors

[kabeljou]

I am building a domestic solar hot water system DIY. Since I live in SoCal, I will be making it an open loop system with light freeze protection.I got a good deal on a set of used Novan Optima II 4x8 collectors. The concern I have is that I do not know the history of these (and neither did the seller), and I am worried that a toxic anti-freeze may have circulated through them in a past closed loop application. Keeping it simple, these are the questions I have:

1) Is there a simple and easy way to test (at home) what was previously used as fluid in the collectors?
2) If indeed a toxic fluid was used, is there a way to purge or cleanse the collectors so that they are appropriate for use on an open loop system?

[mddorogi]

That's a hard one.

I restored some 20+ year old collectors a while back. These days, installers generally use non-toxic propylene glycol, but in the past, it's more likely that toxic ethylene glycol was used.

The simple answer is to run a lot of water through them, but to be safe, after you do that you'd probably want to find somewhere (local health dept?) that could test water that's been sitting in the collectors for a while for toxic stuff. The trouble is, who knows what's been in them.

My old collectors had baked-in crud in there. Even though I purged them quite well, there was still crud coming out of them months later (the heat from actual use cleans them out better than just running water through them for a while). Not a problem for me since I have a closed-loop water only drainback system, so I just changed the water once or twice. Now it stays crystal clear.
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Mark
Dell Point Europa

[Ahshucks]

For cleaning holding tanks on campers we begin by using a bleach & water solution, shake, empty. Followed by a Baking soda & water solution, shake and empty. Just thought it may help you...
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