Type of Copper for solar

Unknown

Hot Rod I use aeroflex epdm with the self sealing flap. It is rated to 257f and is uv protected it is split and easy to put on after the job is finished and the self sealing flap really burns into itself. and it is about a third of the cost of ht.
TONY

Wayco Wayne_2

I've been thinking

about running my lines from basement to roof. I had heard someone say to use L copper because of high temp and pressure possibilities if a problem such as a power outage rears it's ugly head. However...I am planning on using a drainback system. If I have a power outage it just drains back to the resevoir tank. The pressures never get very high that I know of. Why not save a buck and use M copper? Am I missing something. BTW I priced some of the SS line sets. Wowowowowow! the prices bring out the Scottsman in me. Also why not solder?

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Derheatmeister

WW,Yes,why not use Type "M"?

I have used Soft CU in a closed loop but i think on a drain back i would use hard because it does not bend as much forming a trap.

How many Collectors? which brand? and are you using two circs ?
More details/Pix.. Please

Chris Norton

Copper for Solar

You will definitely save a buck using M,, but it could cost you twice as much if you have a blow out. Solar systems, even drain-back, can achieve extremely high temps and pressures. Type M is only rated to 100 psi. The thinner wall tubing will burst at high pressure. That is why the expansion tank, pumps, high vents, and all the other accessories for solar are special. Pressure can kill.

Don't be cheap on this one. Use L.

hot_rod

At 400F

type L is rated at 796 psi, type M at 556 psi.

Heck use baseboard gauge copper if you can find it

Also be sure to compare apples to apples with that solar flex, mainly the insulation. You really should use a HT (high temperature) insulation on solar piping. Price out Armaflex HT for a sticker shock.

Maybe not so much for your own home (free labor) but installing copper with a silver solder joint every 20 feet and insulating it after pressure testing really eats up the labor hours and dollars. That's where the pre-insulated, pre-wired solar flex products save, or MAKE you money.

Roll it out drop it down the wall, and two mechanical joint connections. No torch required.

I installed a drainback in my shop this summer. one concern was the ability of the corrugated stainless to drain back completely without freeze ups. so far so good with a handfull of days in the teens.

hr

Chris Norton

I stand corrected

Hot Rod is correct, M is scientifically rated to 556 psi. But I am not aware of any code that allows for its use in a system where pressures exceed 100 psi. There may be one out there, but none that I have seen.

The solar flex products work great if you can find a good path to allow for the drain back and they do save a boatload of labor cost.

hot_rod

If you go drain back a 30LB

relief valve, solar rated of course, would be my suggestion. I like the pressurized drainbacks to keep that boiling point up and eliminate 02 issues with a sealed system.

I'm trying mine with a plain steel Ergomax tank as the drainback and HX device.

I'll look inside next year with my Ridgid SeeSnake to see how the tank is holding up. I pre-charged mine to about 8psi. it will run up to around 15- 18 when running 180F. No expansion tank required as the air space is the expansion space.

hr

Unknown

M is fine

and if your system is large enough that you use 1 1/4 use dwv.. cheaper yet. There is no pressure in a drainback and pressure systems have a relief valve. Look at the copper they use for fin board or the stuff they use on thos chrome sweat lav valves.
TONY

Wayco Wayne_2

Yes

I spoke with Darin after he used the flexible solar line set. He said it really helped cut down on installation time, and as we all know, time is money. WW

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Wayco Wayne_2

You say to use

silver solder on the joints. I guess 95/5 is out due to high temperatures. It's hard for me to imagine such high temps. I guess it's because I'm a newbie to Solar and have limited experience to draw from. Would 15% brazing rod be OK. I would think so. WW

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