[RE-wrenches] Stiebel Eltron SHW Collector condensation issue

Tue Jun 21 10:03:00 PDT 2011

After 25 years of installing solar thermal panels, we have come to the unfortunate conclusion that they all suck.  We have had out of the box failures on all panels we have used... and we are a very, very, very small company.   We pressurize our solar thermal systems to 60-80 psi and let them sit for 3 days.  If they hold that pressure... like a ROCK, we complete the install.  What we find, as often as not, is some little piddly leak somewhere in the loop.  Micro holes are not an uncommon encounter in panels.  So, we then have to wrestle the solar thermal manufacturer into first believing their "infallible" product is leaking , "out of the box"  and then pay, out of OUR pocket the substantial labor costs for its replacement.  So far as I can tell, all solar thermal manufacturers warranty their panels for 10 years.  But, they only cover $100.oo in labor costs to replace a defective product.  This does not begin to cover our labor costs. 
 Consequently, I have started down the road, (without success so far) of demanding solar thermal manufactures to stand behind their products with a 5 year $500.00 Labor warranty.  I have talked to a ton of solar thermal manufacturers and  they all say the same thing.  "Our panels are the best.   Our failure rate is less then 2%.  We warranty them for 10 years, but we only pay $100.00 labor to replace those that are defective out of the box."  I can't even get the evacuated tube guys to stand behind their product with a decent labor warranty!

Perhaps if more than one solar Bozo stands up and  says, "Enough, we want a panel with a 5 year $500.00 labor warranty".  A manufacturer might see the competitive edge of being the first to do so.

Sincerely, 

Andrew Koyaanisqatsi
President
Solar Energy Solutions, Inc.
Since 1987,
Moving Portland and Beyond 
to an Environmentally Sustainable Future.
503-238-4502
www.solarenergyoregon.com 

"Better one's House too little one day
than too big all the Year after."

From: August Goers <august at luminalt.com>
To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
Sent: Tuesday, June 21, 2011 7:19 AM
Subject: Re: [RE-wrenches] Stiebel Eltron SHW Collector condensation issue

Hi David -

Doesn't sound fun. We experienced a similar problem with a 10-collector system with Schuco Slim-Vs about 3 years ago. The collectors had lots of condensation build up in them, especially during the rainy season. Schuco stepped up and gave us new 2nd generation collectors under warranty. The new collectors do not have the condensation problem. Apparently they redesigned the ventilation method. Generally speaking I like the Schuco product although now we're noticing a browning effect occurring near the in inlet and outlet pipes on the absorber plate on Slim Vs installed a few years ago. I have yet to deal with this issue.

It sounds like Stiebel is still working out their design. You'll probably want to make sure that they have it fully figured out before replacing the old collectors under warranty otherwise you might have the same problem!

Good luck with it.

Best, August

From:re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Dave Palumbo
Sent: Monday, June 20, 2011 12:58 PM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] Stiebel Eltron SHW Collector condensation issue

SHW Wrenches,

Our first experience with SHW flat plate collectors with a condensation issue on the inside of the collectors’ glass cover. The system has two Stiebel Eltron Sol 25 collectors (88” x 48” each) with a 82 gallon single heat exchanger insulated tank in the basement of the home, with a SOM 6 solar loop controller. System installed fall of 2008.

Condensation problem was first noticed by homeowner late last December. The collectors’ manufacturer, Stiebel Eltron, instructed us to watch and see if the problem resolved on its own. It did not. Stiebel then instructed us to drill small holes through the sides of the collectors near the top for venting and more holes through the sides near the bottom for draining the collector (see attached pdf for Stiebel’s venting advice). We did that in early May of this year. The homeowner called us back with the same condensation issue. 

Stiebel then sent a bag of plastic insert venting plugs that required us to drill out larger holes in the side of the collectors and pop these vent plugs in. Plugs appear to be an attempt at making more venting area while trying to keep the rain out. After we installed these plugs we still have the same issue, homeowner still sees condensation and poor performance from the SHW system. 

The homeowner is now asking for new collectors under warranty.  Have others experienced a similar SHW collector problem? And have collector manufacturers stepped up with new collectors?

Thanks,

David Palumbo
Independent Power LLC 
462 Solar Way Drive
Hyde Park, VT 05655
www.independentpowerllc.com 
NABCEP Certified PV Installer
Vermont Solar Partner
23 Years Experience, (802) 888-7194 

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