[RE-wrenches] Need SDHW Flexible Tubing recommendation

R Ray Walters ray at solarray.com
Thu Oct 28 12:32:46 PDT 2010


HI Allan;

I just recently used some flexible stainless steel line on an old radiator/ boiler system here. It had special fittings, that I was a little dubious of at first, but it all worked well, and was easy to install.
I believe it was the Easy flex product.
The only problem I encountered, was that it was a little hard to get a clean cut on the SS flex line (sort of the same problem as cutting metal flex conduit)


Some things I had trouble with, when I did off grid, PV direct glycol SDHW:
1) don't use the Ivan labs pumps, they're too low head to pump the glycol when its cold in New Mexico. I had the misfortune of having to trade several out one winter (why I don't do SDHW anymore)
2) put a ball valve between the air bleeder valve and the rest of the system, so that it can be isolated once the air is out of the system after a few days. I had those start leaking after a while, as the glycol causes them to gum up over time, then it leaks enough Glycol out, to lose pressure and crash the system.
3) Even the high temp foam insulation deteriorates from the high temps near the collectors, I'm not sure what's available now, but get the highest temp rating insulation you can find. (FIberglass?) Also, paint/ coat it, as the UV radiation breaks down the insulation from the outside.

Sorry if I'm going on so, you probably had all this info already.


R. Walters
ray at solarray.com
Solar Engineer




On Oct 28, 2010, at 10:21 AM, Allan Sindelar wrote:

> Wrenches,
> I'm installing a flat-plate SDHW system in my own off-grid home; a PV-direct closed-loop glycol system feeding a storage tank with two internal heat exchangers. The glycol lines only need to run a distance about 25' (each line), but they need to take a circuitous route through roof and attic framing that doesn't lend itself well to flexible copper tubing. I have heard very good general recommendations about the insulated flexible corrugated solar thermal line kits - expensive but worth it. One or two stainless or copper tubes with insulation and sometimes a sensor line included, with fittings to adapt to pipe thread or copper tubing.
> 
> At SPI there were a whole raft of manufacturers showing product - I mostly just grabbed literature:
> Easyflex
> Solar-Trac by OmegaFlex
> Caleffi
> Aeroline
> 
> Who has used this product? Whose product do you like? Needs to be well made and readily available to ship.
> 
> Thanks for any advice; I need to get this ordered and in place before the insulation is sprayed into the roof.
> Allan
> -- 
> Allan Sindelar
> Allan at positiveenergysolar.com
> NABCEP Certified Photovoltaic Installer
> EE98J Journeyman Electrician
> Positive Energy, Inc.
> 3201 Calle Marie
> Santa Fe, New Mexico 87507
> 505 424-1112
> www.positiveenergysolar.com
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