Issues with line set to solar panels

gasfolk

a stagnated solar collector from the line set to the boiler room? If there is enough solar storage in the basement, can a tank in the attic be mixed with water circulating from the basement to transfer the heat without exceeding the limits of pex?

A new line set would necessarily be external, on the front (south) face of the house, but I can use the pex line set for other things if there is no alternative.

Thanks,

gf

gasfolk

Advice on solar line sets?

With a set of 3/4-inch pex to the roof, can anyone offer advice on the ideal line set? Are there benefits or limitations of pex lines? Is it worth abandoning the installed pex lines for an external line set of superior material?

Thanks,

gf

Mark Eatherton

DON'T use PEX

The collectors WILL see stagnation temperatures of 350 degrees F. This WILL cause the PEX to fail, and I know this based on FIRST HAND information.

Don't do it. Look into Caleffi. Or consider replacing with copper, but DO NOT use PEX.

ME

gasfolk

Is this an option?

Hello Mark, and thanks for the good warning.

Is it practical (or at least possible) to put the solar storage tank in the attic, near the panels, then use a mixing device (valve?) to temper tank water with heating system water to get down to a range acceptable for pex? Has anyone used or heard of an attic tank? Besides structural issues and potential for leakage, which both seem manageable (we have a bathtub on the third floor), is there a good reason not to do an attic tank?

The pex line set was for an intended extension of heat to the third floor, but through three seasons, the third floor heats well by passive airflow. So, a convenient, though imperfect, line set.

Thanks,

gf

hot_rod

why risk it

for the few dollars difference in a suitable tube and PEX, that is not even close to the required temperature rating.

Copper works. Insuated stainless steel solar linesets work. Heck, even steel pipe would be better than pex.

Chose a tube that can handle those 350F plus temperatures on a daily basis, like when you go out of town, the power goes out, pump, controller, or sensor failures.

Darrin has some nice pictures of a lineset cover he used to hide solar piping down the exterior of a home.

Here is a piece of pex from my shop solar install. i'm from the show me state, I had to see for myself!

hr

Royboy

worth 1000 words!

and all sorts of potential grief avoided.

just an hour ago I discovered that a "bargain" tank - a new 80 gallon Bradford White indirect - obtained by a homeowner to be used as a solar storage tank is not suited to the application because it has a aluminum/pex heat exchanger which is a) aluminum on the solar side and b) rated only to 180 degrees. never knew that some indirect heat exchangers were of this construction and feel bad cuz in my ignorance I OKed the purchase by the homeowner.

I take it as a reminder to look bargain horses squarely in the mouth ... and not all materials are suited to solar systems!

Roy

Derheatmeister

VERBOTEN or Forbidden
It shall be to use Pex in these applications!

That is a very bad application,I have seen solar direct application that had massive Pex failures after Power failures and reapplied power and elevated temps.

It is ugly

gasfolk

That looks exciting! Thanks everyone for the heads up.

gf

gasfolk

I really appreciate being saved from this. Thanks everyone.

gf

Mark Eatherton

Yeah butt...

and you know, there's a butt in every crowd... You then take the chance of freezing and breaking not just potable water lines, but the tank too, and talk about a water disaster...

And then there's the whole weight thing...


I'm afraid you're gonna have to abandon those lines in favor of a more robust material...

ME