[RE-wrenches] Need SDHW Flexible Tubing recommendation

[Bill Loesch]

Allen & Ray,

Ray understands the necessity for the smooth cut on the Corrugated Stainless Steel Tubing (CSST) as the critical element spot on. All the manufacturers I am familiar with sell a special tubing cutter for this purpose. (The only thing special about it is the non cutting rollers are formed to the same convolutions as the CSST to make it harder (not impossible, but harder) to screw up the cut. Initially I resisted buying the specialty tool but I wasted enough tube and time with bad cuts that eventually I saw the light. A very sharp cutting wheel makes the cut even easier. 

The non cutting profile roller wheels can be ordered separately from some manufacturers if you want to have your copper tube cutter to do double duty.

As you already know, the armored cable is a spiral conduit wrap, the CSST is not a spiral wrap.

Bill Loesch
Solar 1 - Saint Louis Solar

  ----- Original Message ----- 
  From: R Ray Walters 
  To: Allan at positiveenergysolar.com ; RE-wrenches 
  Sent: Thursday, October 28, 2010 2:32 PM
  Subject: Re: [RE-wrenches] Need SDHW Flexible Tubing recommendation


  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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