to glycol, or not to glycol?

AKO

Doing a renovation where it'll be necessary to get to certain areas by going through unheated spaces.

I could see the argument for not using glycol (propylene - not ethylene) for the reason that those zones served from this piping circuit will be getting heat during times when freezing is an issue. But this theory is clearly frought with holes, so...

your comments please.

Thanks in advance to those with so much valuable time in the trenches (or basements and attics, as applicable). Happy holidays.

Jack, CVMS

Will you

have full time circulation to those zones?

hr

At last resort!

It is expensive, messy, leak prone, maintenance intensive, and very ugly when left un attended. I use it mainly on snowmelts.

Could you insulate the pipes with 1" wall. Plenty of residential baseboard systems running near, and in, outside walls without glycol.

Maybe a freeze stat like attic mounted air handlers with hydronic coils use.

Dan Foley taught me that one!

hot rod

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Richard D._2

Hey Hot Rod

I never saw a freeze stat.Who has them?? Thanks Richard

hr

Try Dan Foley

He has done this often with air handlers mounted in cold spaces.

We worked together, along with Flag, on a job in Memphis. The upstairs had radiant floor heat with a hydronic coil in an attic mounted air handler, as a second stage to the radiant.

Hopefully it will never need to run, but it is sitting above the insulation in a well ventilated attic. Very real freeze potential.

I'm not sure if there is a specfic product. All you need is a setpoint control or a cap tube aquastst that would "make" when the temperature dropped to 32F. This would call on the pump or zone valve to move some water. Plenty of controls like this in the Johnstone catalog.

hot rod

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AKO

The branch that would be exposed to unheated attic areas would serve at least two zones (valves, not circ pumps), and they would only get flow when one of the zones calls for heat. -- I really don't expect a problem under normal circumstances.

I like the freeze stat idea as a safeguard. Actually, it could be a simple stat controlling a bypass valve, located after the branch comes out of the unheated area. Again, I don't really think it's likely to be a problem, so I may not bother.

Thanks for the input.

Douglas Hicks

anti-freeze tester

About 10 or 12 years ago I had a need for an antifreeze tester, for anti-freeze loops in sprinkler systems. I purchased a Misco unit, just a basic, nothing fancy kind of tool. It worked every time. Then I hired a new tech and needed another tester. This time Misco had a new tester, a digital fiberoptic refractomiter. Thing cost about $600.00. The old basic unit and the expensive tool never did read the same. My tech finally bought her own, and I gave the expensive tester to another tech. He did not like it. we now had 3 testers, the expensive one and two basic models. The basic models gave hte same readings, the expensive ones never agreed with the othersm, and oftne gave diferent readings with the same sample. I finally called Misco. I was told the Digital Fiberoptic Refractometer was perfect and we did not know houw to use it. I kept complaining and was finally given permission to return it the to factory. Guess what, it was not perfect and needed repair. I got it back. I now have had 3 tech and myself use it, and none of us liked it nor did we trust the readings. Tonite, Jon told me he did not like it and wanted a new one. The thing needs to be calibrated each time it is used, takes too long to calibrate and still does not agree with my old tester. I am going to order a new 7084 VPT tommorrow. Any one want to buy the fancy one? I'll sell it for $150.00 and shipping is included.

Douglas Hicks
General Fire Equipment Co of Eastern Oregon, Inc

Mark Wolff

glycol pros and cons

Yes glycol is expensive and messy, and will reveal leaks that water and air tests will not always, however, you must weigh the cost of broken pipes (and possible H2O damage?) against that. Here in Alaska, the general rule of thumb is that anything in a slab or outside must be charged with glycol, and any system operating in a temperature zone that sees -30 F or lower should as well. I personally put it in as many systems as possible, to reduce broken pipes (one freeze-up left a 2 story 1600 sq ft house with 57 bursts). The cost should be between $6-$10 per gallon depending upon your location, and it can be mixed up to 60/40 for cost efficiency when a -100 F burst protection is not needed.

Mark Eatherton1

The trick...

is to not allow anyone to make an auotmatic make up to your system and allow inadvertent dillution.

If glycol is a must, then automatic make up is a must NOT!

Use a PIG.

ME

Bob Bona_4

I've been

doing the tekmar 150 for years. Sensing bulb in the attic, control in the basement. Tie in a fan center to start the circ.

It's cool to see what the attic temp is from the cellar!

I avoid glycol any way I can.

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