[Greenbuilding] SIP and Drainback Solar Hot Water system

[wmdorsett at sbcglobal.net]

Mike, we used to install Cornell batch water heaters and would put two 
layers of pipe insulation with one following through the roof jack to 
the water heater and the second layer from the collector to the roof 
penetration, cut into an upside down funnel down glued over the rubber 
gasket at the top of the roof flashing so water would flow to the 
outside of the penetration. The theory was that as sunlight deteriorated 
the rubber, a leak wouldn't develop where the pipe went through the roof 
jack. Seemed to work as we never had call backs for leaks.

Bill Dorsett
Sunwrights
Manhattan, KS

Mike Forbes wrote:
> Hi all,
> I'm just finally sitting down with a beer after installing the roof portion
> of my drainback system. I have a question regarding melting points and am
> hoping someone might have an opinion on this.
>
> What i have:
>
> 12" SIP roof (EPS foam) w/ metal roofing
> 128 sq. ft flat plate collectors (4 - Sunearth EP-32's)
> approx 30' of 3/4 copper run to storage tank
> Armacell pipe insulation everywhere except where it penetrates the roof.
>
> What i'm wondering:
>
> as i was making the roof penetration I started thinking about the temps the
> pipe would expect and what that would do to the EPS foam in the SIP.
> Looking at the MSDS on EPS foam it begins to soften at 175-220 degF for most
> of the SIP manufacturers out there.
>
> What I did:
>
> Drilled a 2" hole through the roof.
> Made a copper pipe insulator to hold the 3/4 copper in the center of the
> hole
> Used a silicone boot to seal the hole from the weather along with the smelly
> sealant...
> There is approx 1/2"-5/8" airspace around the copper pipe going through the
> SIP.
>
> What should I do:
>
> a) nothing, the airspace will keep the EPS from getting too hot
> b) put Armacell (230 degF working temp) around the 3/4 pipe in the SIP
> c) something else, suggestions?
>
> Thanks a bunch,
> Mike
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