Changing Grumman sunstream 332a SHW collector pipes

Stiffsocks

Hello everyone. What is a great site to stumble upon. Recently I bought some old but new Grumman sunstream 332a shw collectors and was just wondering if there is gonna be any unforeseen issues to change out the copper piping system inside the panels?  Also what is the best way to get to them.  It has screws on the top glass and rivets on the bottom.



I originally was gonna use these with a glycol system but now I want to make it a drainback system if possible. It has 3/4" copper headers but only 1/4" Nom risers which is the problem. I would like to make them 1/2" risers.



The collectors are from 1980 so there is not much info online about them however I did find the attachment found below with some specs.

That is all I need guys. I really appreciate everyone time and thanks for reading this.

joseph annon

Grumman

The pipes are soldered to to the absorber plate and brazed into the headers removal would be difficult and then your absorber plates won't match up size wise to new pipes.

Most collectors I know have including the Grumman collectors run just fine on drain backs with existing piping. There are several large arrays that I have worked that used Grumman collectors in drain backs.

Stiffsocks

Collector Angle or ideas?

I live in central PA so my winters get pretty cold with very short days of sun. Idk if its even gonna be worth it to use it in the 3 coldest months here.



Is there a certain angle/degree for the panels that would work the best with 1/4" risers?

 

Would the long side of the panel being completely vertical be the best option? I did see a comment in another thread about feeding the lower header from both ends...



Any advice would be greatly appreciated. I just was under the impression that under 1/2" for risers was not acceptable for drainback. So if there is another way or a workaround, Im all ears



Thanks again for a great forum and people.

joseph annon

tilt

Generally tilt is your latitude plus 10 degrees.

Biggest thing with drain back is that all piping slope back to drain back tank and that there are no low spots or bellies that will hold water and stop the draining of the collector and the piping.



As for usefulness in winter someone with experience in the north would be better able to tell you about heat gathered.  I know that there is a lot of solar in places like New Hampshire. Germany also has a lot of solar and I believe they are near your latitude.

My thoughts on that are that it is at least some heat you have the system so use it as much as possible.



A question what are you planning on using the solar heat for?

Stiffsocks

DHW

Its gonna be used to preheat my domestic hot water. I have almost a 200 gal tank with 2 4x8 collectors. Its a fairly short run from the panels to the tank and most of the plumbing is vertical inside an enclosed porch(not heated) then into my basement. So there should be no spots that water doesnt drain.



I have been researching typical shw systems for a while now. I get the basic concept of most of it. I just need to figure out how to tweak the system to use these collectors with the small 1/4"Nom risers(3/4" headers) for a drainback system.



Adding to my suggestions for a fix from my last post, would using larger copper plumbing from collector to tank help with the draining?

I do have a new Grundfos 15-58 and a older bronze taco of some sort with enogh head to use any size supply/return line.



Thanks again guys for ur time.