Solar Roof Mounting Question

[leibin]

Hello! I just scored 6 Fafco 4x12 panels for $150 on craigslist including the connecting hardware, vacuum release, ect. I figured they would be in pretty lousy shape at $25 a piece, but they're actually in pretty good condition compared to the last set of panels I bought for our last pool, and I'm excited to get them put up!

So, in talking with the guy I bought them from, they were on his roof, but the installer had placed the panels in such a way that most of each panel was on his tile roof, but the bottom headers were on his asphault shingle roof. He ended up having a major leak, because the bottom headers were not allow water to freely flow off the roof because you get leaves, dirt, ect collecting there over time which causes water to pool.

I woke up this morning and started to think about my last setup - I built a large rack in the yard for the panels because getting them to my roof would have been a major PITA But, in having them on the rack, I too noticed that I had a ton of debris collecting under the panels, especially underneath the lower headers. Now that I'm about to mount these on my roof above my Patio and a room at the back of the house, I don't want to have a similar issue that may cause a leak / standing water down the road from rain, ect.

I've been searching the site, and the internet, but I can't completely figure out what I need. Is it normal for the headers to just sit on the roof, with some mounting strap holding it in place? Is there a way to get the headers lifted slightly so that ran water and debris can freely migrate downhill? Or, do you just mount this, and then every so often, head up there and clean out from under the panels?

Any insight would be much appreciated!

 

[JasonLion]

Typically the panels are simply resting directly on the existing roof. But some people mount them up on frames 2 or 3 inches above the roof.

The panels should be tilted a little so that any water/debris will tend to run off to one side. The panels will also drain more easily that way.

 

[leibin]

Thanks Jason - ok, makes sense. The roof that I'm mounting this on is barely sloped at all, just enough to tilt the panels so that I don't get air trapped I'll just make it a habit to get up there a few times a year and clean under the panels just to be safe.

Have a good one!

 

[leibin]

One more quick question on this - I'm planning on placing T's in the lines going to the solar panels so that I can drain them in the winter - but, I can't find what I need. I'm looking for something that is 2" for one socket of the tee that I can use for a drain. I know there has to be something that most people use - any insight?

 

[JasonLion]

It is common to use a reducer to 1" or even 3/4" and then a threaded adapter with a hose bib screwed in.

 

[Isaac-1]

What Jason said, here is the drain / partial bypass for self draining setup I built for mine.

The red valve lets me let a trickle flow bypass and drain back down from the inlet side and the black handle valve lets me drain to a hose or the ground. The wire is tying the drain valve closed because just after I installed my panels a small tree limb fell and bumped the valve open one night.

 

[leibin]

Thanks Jason and Isaac - nice pic, too Can I get your input on this picture? There is not really a way to get my drain at the lowest point of the pvc runs. If I was to disable solar in the winter and leave the spicket / drain valves open, would I still need to worry about the pipe that is slightly underground, or would having the valve open allow the water to expand up the pipe if needed in freezing weather? Apologize in advance for the great artistry

 

[Isaac-1]

In that case you would probably be better off with a drain as close to the end of the loop as you could get and a plug you could remove on the other side of the loop where you could blow out the water with a shop vac, etc. You would also want isolation valves for both sides of the solar loop.

Ike

 

[leibin]

Hey Isaac,

Ok, that's a good idea on blowing the lines out - any suggestion on the removable plug? I suppose I could just take the shopvac onto the roof (fortunately, it's pretty flat where the panels will be!) and then disconnect the in and out to the panels, put the drain at the equipment pad (and open it!), and then blow the lines clear from the roof?

I plan to place an isolation valve on the input and output from solar, as well as a check valve coming out of the filter, and another on the solar return to system - sound correct? For the isolation valves, I suppose I would install that first, and then the drains directly thereafter?

Thanks again, really appreciate your input!

 

[Isaac-1]

I would just use a 1.5 or 2 inch T fitting and put a screw in plug on one side, you can see one in my photo with the light blue teflon tape showing.