Pics of 2 DIY systems being built / Hot Air Collectors and Drainback System

solarhotairpanels · 11-06-13, 08:22 PM

Hey, thanks for the nice comments.

Appreciate it..

on the drainback system the answer is YES, air needs to be introduced into the return piping from the collector in order for the water to not get vacum locked in the piping.

Also I suggest using 3/4 copper pipe to/from the collectors on a drainback system so there's ample enough room inside the copper pipe for the water to drain easily.

What I did to allow it to drain was on top of my drainback tank just before the water dumped into the drainback tank I added a T fitting and stuck a 1/2 inch piece of copper tubing straight up into the air off the 3/4 return pipe.
I put a ball **** shut off valve on the 1/2 inch tubing kinda like an air vent.
I just leave the ball **** slightly cracked open to allow air to enter the 3/4 copper drainback pipe.

Next, just to make sure everything drained back quickly I installed a vacum release valve on the collector up on the roof.

I put it on the outbound copper pipe right where it leaves the collectors 'highest point' of the collector piping.

That allows air to enter the pipe outside at will anytime the system pump shuts off so it's impossible for the water to become vacum locked.

If you or anyone else has any other questions at all just email me or post here anytime.

I love talking about this solar stuff.

Pat from Rhode Island

11-06-13, 08:22 PM	#10
solarhotairpanels Helper EcoRenovator Join Date: Mar 2012 Location: Warwick, Rhode Island Posts: 92 Thanks: 22 Thanked 29 Times in 18 Posts	Hey, thanks for the nice comments. Appreciate it.. on the drainback system the answer is YES, air needs to be introduced into the return piping from the collector in order for the water to not get vacum locked in the piping. Also I suggest using 3/4 copper pipe to/from the collectors on a drainback system so there's ample enough room inside the copper pipe for the water to drain easily. What I did to allow it to drain was on top of my drainback tank just before the water dumped into the drainback tank I added a T fitting and stuck a 1/2 inch piece of copper tubing straight up into the air off the 3/4 return pipe. I put a ball ** shut off valve on the 1/2 inch tubing kinda like an air vent. I just leave the ball ** slightly cracked open to allow air to enter the 3/4 copper drainback pipe. Next, just to make sure everything drained back quickly I installed a vacum release valve on the collector up on the roof. I put it on the outbound copper pipe right where it leaves the collectors 'highest point' of the collector piping. That allows air to enter the pipe outside at will anytime the system pump shuts off so it's impossible for the water to become vacum locked. If you or anyone else has any other questions at all just email me or post here anytime. I love talking about this solar stuff. Pat from Rhode Island Last edited by solarhotairpanels; 11-07-13 at 07:50 AM..