Percentage of glycol added?

George_10

do you folks routinely use in systems that need freeze protection? I know there are minimums, but I am trying to get an idea of what is usually done. Also does this vary with a snow melt system vs an inside system.

Any answers would be very helpful to me.

Thanks for your help.

George

flange

ive used it a lot for chiled water systems for mri units and such, they generally dont like to see less than 35 percent solution, i usually go to forty percent. the level of protection you may need will depend on the climate and the expected low temps yiou will encounter. keep in mind that you must anticipate this before sizing equipment, due to reduced heat transfer.

George_10

Reduction

is this reduction like on a steady scale or does it have some kind of parabolic curve. I do not want to belabor the point, but I am asking for my own education.

Unknown

Even in the north,

> is this reduction like on a steady scale or does

> it have some kind of parabolic curve. I do not

> want to belabor the point, but I am asking for my

> own education.

Unknown

Even in the north,

50/50 is a little stiff for boilers. 30% is the mildest I ever installed, George.

We never went below -30 out, and I worried about some of the 30% jobs when it got real cold out. It hit -30 several years back during the Winnie Ice Fishing derby. Everything I owned froze solid in the icehouse, even with the woodstove screaming. The bait can froze solid, indoors on the floor, overnight.

Noel

George_10

How do

you get the bait out of the can? Or better yet do fish like frozen bait? Sure having fun with these lower temps today with the people I am talking with. Talked with a guy who was in NH last night. Said the only reason his face did not freeze at -35 was because he had just come out of a watering hole. Another reason to raise a glass.

Mark Wolff

Standard mix

60% glycol to 40% water is a standard mix for us here in Alaska. In the mild climates it is fine. In the interior or up north it is 100% premixed glycol with a -100* burst protection.

One thing to remember is that at 100%, burst protection is -100 but freeze protection is only around -65 and flow protection is even lower.

The glycol will stop flowing first, freeze second, then burst third. A 60/40 mixture allows for flow down to around -30* F.

hr

On the low end

30% is as low as you want to mix. At this % you may want to beef up the inhibitor package, as it is pretty diluted. The Dow brands with HD (heavyduty) can be blended down to 20%.

Generally 60% is as high as most manufactures show on their tables. Above this some even start to go the other way and burst point starts going UP!

Actually, straight propylene glycol at -40° is no longer "pumpable" with a centrifugal pump.

Always check with the manufacture, when you plan on running against the limits Not all glycols are created equally.

Actually for extreme temperature use, ethylene based glycols are a far better choice. Quite a bit less viscous than propylene. Mainly used in commercial applications as pump requirements become more of a consideration. Toxcitity issues need to be addressed, however, with EG's. Not a good choice for ground loops, etc.

hot rod

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perfesser

Not Ethylene Glycol! (Ultra boiler uses Fernox)

Hot Rod,

Most residential systems contain plastic and rubber components that will not tolerate ethylene glycol. It eats them up and then we're dealing with lots of leaks. Propylene glycol is non-toxic and not harmful to these components.

By the way, the new Weil-McLain Ultra boiler requires a propylene glycol with aluminum inhibitors (e.g. Fernox)

hr

Not exactly perfesser

the same rubber and plastic components in residential applications, could be found in commercial. Could they not? Pump gaskets, ball valve stem seals, check valves, zone valves, etc.

Dow makes DOWFROST which is a propylene (non toxic) and DOWTHERM which is ethylene based. Either can be used for residential, but most installers prefer the propylene for it's non toxic properties.

Actually Rhomar, Hercules, and Nobel now market "all metal" friendly glycols, or inhibitors. Including aluminum.

Fernox makes an inhibitor to add to "technical grade" glycol, used to be sold through Heatway as Alpha 11. CP-3 for plain water.

There was some concern about some of the ingredients and the EPA "list" Also some issues with shelf life possibly?

The US manufactures are keying into the need for all metal and all plastic friendly hydronic chemicals

Might be time for the tubing manufactures ro reconsider offering treatment for their systems.

hot rod

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Mark Wolff

?????

Hey Hot Rod, we get Hercules and a local Alaska brand premixed and rated to -100* F. They both recommend NOT mixing it any at all, and even at full concentration it pumps just fine; granted the heat transfer is a little slower, but really not that noticable. Maybe they don't have good glycol where you are at?