Drainback system design - Page 2

ESharp · 12-21-13, 01:41 PM

Yep, http://ecorenovator.org/forum/solar-...r-project.html is the one.

I ended up using PEX on the return side (due to an ~90' pipe run). It does have better properties than PVC, but I may end up finding out the hard way that it is not enough. Mikesolar suggested in my other post to use a few feet of copper at the start of the return.

Dr. Ben also specifically recommends against it: PEX in a Drainback System? A 'melted mess' picture is there...

Mikesolar · 12-21-13, 05:25 PM

I'm not a fan of PEX for anything that needs water temps above 70C (158F) although it is rated at higher than that, and definitely not when the temp could hit boiling like almost any solar system. Some of the home made panels won't get up there so I think that is fine but I have seen too many messed up systems from tubes blown out at the fittings.

12-21-13, 01:41 PM	#11
ESharp Lurking Renovator Join Date: Apr 2012 Location: NS, Canada Posts: 21 Thanks: 1 Thanked 9 Times in 6 Posts	Yep, http://ecorenovator.org/forum/solar-...r-project.html is the one. I ended up using PEX on the return side (due to an ~90' pipe run). It does have better properties than PVC, but I may end up finding out the hard way that it is not enough. Mikesolar suggested in my other post to use a few feet of copper at the start of the return. Dr. Ben also specifically recommends against it: PEX in a Drainback System? A 'melted mess' picture is there...

12-21-13, 05:25 PM	#12
Mikesolar Master EcoRenovator Join Date: Aug 2012 Location: Toronto Posts: 958 Thanks: 40 Thanked 158 Times in 150 Posts	I'm not a fan of PEX for anything that needs water temps above 70C (158F) although it is rated at higher than that, and definitely not when the temp could hit boiling like almost any solar system. Some of the home made panels won't get up there so I think that is fine but I have seen too many messed up systems from tubes blown out at the fittings.