Glycol question

George_10

when glycol is left in a system and not tested, what actually happens. Does it change color or become more viscous. I understand it becomes acidic.

I would like to hear from those that have actually seen an untested system with old glycol in it.

Just trying to become better informed.

Thanks

hr

All the above

O2 depletes the inhibitors after a while. Non barrier tube will allow enough in over a period of time. Higher temperatures "lure" more O2 through the tube wall. Plenty of other O2 ingress points in hydronic systems.

If it is cooked beyond it's operating range it goes bad. Smell and color will indicte cooked, as well as ph. Fairly common in solar panels that go stagnent for periods.

I have heard it can seperate if left unpumped for a while. I'm not sure I have seen this first hand. Maybe the "bargin brands" are more inclined to this.

The 800 tech support number at DOW heat transfer fluids is a wealth of info.

hot rod

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canuckDale

pH

Without treatment/pH buffers it will form Aldehydes.
Be it ethylene or propylene.
Which will enventually turn into Acetic Acid....Lowering the pH.
Needs monitoring.

kevin coppinger_4

what is the best....

way to floush it out of a system? I have a job where it was put into a system left for two years and then wanted it out. I "purged " out the lines but the smell still persists after a month or two. The tubing was entran 3. kpc

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sootmonkey

anti freeze

My experence with anti freeze is that after 3 years or so it will start attacking the packing/gasket material in the componets of the system. Our co. only uses anti freeze as a last resort. Such as unheated spaces were the heat pipes run through. Old houses with split stone foundations. Any place that has a history of freezing up with the system running. As others have said here, the ph level changes, and turns asidic. I have seen to many systems that have had anti freeze put in them 5,7 10 years ago, and left untested/untreated. NOT PRE T. I reccommed replaceing the anti freeze every 3 years.

Drew_2

Propylene Glycol

Some of the things said about propylene glycol are accurate. Others are old wives tales or misunderstandings. A good explanation would take a lot of space and there would be questions that wouldn't be answered.
If you would like a better understanding of propylene glycol and how it works give me a call or chase me down at Wetstock in Baltimore. Ph: 800-678-6625

Drew/The Noble Company

Mark Eatherton1

Come on Drew...

Tell us what you know... We've got plenty of time. Don't be bashful:-)

ME

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hr

the smell

could be from that tube. Seems to stay with it forever. Or the entran combined with a burnt glycol odor the gets into the rubber, would be hard to get rid of.

After a good hydronic system cleaner and flush. Add the conditioner.

And some peppermint oil If you want a "different" smell.

hot rod

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Tom Meyer

I can see Drew getting a thousand calls

If you've got the time to write it, we've got the time to read it, Drew.

Now you've got me curious. To paraphrase Detective Joe Friday "Just the facts, man. Just the facts."

Tom Meyer
Senior Designer/Trainer
Precision Hydronics Corp
www.precisionhydronics.com

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Earthfire

Knowledge

Always looking to learn

Bob Cat_2

does it attack after three years or

I always wondered why the packings nuts on the taco check valves ALWAYS leak when I put glycol in a system. Also when I fill an exsisting system that had no apparents leaks glycol seems to find a way out. THis seems to happen fairly quickly not after three years.

Duncan_13

Come on Drew, help us out here !

We invite you, please. C'mon in, have a cuppa Joe. Taking up a lot of space for a good explanation and to dispell old wive's tales and misunderstandings is not a problem. Feel free.

And if there are still a couple of unanswered questions after an explanation, don't let that stop you either - they will get asked.

If you work for The Noble Company that sells NoBurst, you bring credibility to the issue. I see NoBurst now makes hydronic anti-freeze, cleaning, anti-corrosion, and anti-foaming agents.

As you can see from the replies, if you say "I know the answer, but it's too long to explain" the folks that have questions might feel snubbed. Maybe even resentful, like they've been blown off. There are a lot of folks here that are thirsty for good information.

There's no reason not to point out the benefits of a good product!

Drew_2

Glycol

Boy, you guys won't give up. Every time I start to respond, the phone rings and it's another "paying customer" with questions.

Now I have time to address this Motley Crew.

1. George;PG left in a system. Every time PG is heated it tries to create acid. The temperature and the longevity of the heat accelerate this. The inhibitor package that is in the product should work as a buffer to slow this process. It can change color from the oxides and bacteria that may be in the system. It should not become more viscous.

2.Hot Rod; O2 attacks metal that creates oxide, inhibitor attacks oxide. This depletes the inhibitor. Yes, bargain brands use less inhibitor (less reserve alkalinity). Can't say I've ever heard of PG separating from water.

3.Sootmonkey;packing/gasket material: This is a case of poor packing/gasket material. The question is "If you have a head gasket on your car start to leak, would you blame it on the oil"? Yes, the pH will change over time. This raises the second question. If systems need to be maintained, why hasn't the fluid been checked? We check the oil & antifreeze in our vehicles for problems.

4. CanuckDale;pH: I'm not sure about this one without looking it up. I believe Acetic acid is what is found in vinegar and is the main ingredient in aspirin.

5.Bobcat; packing nuts: If it can leak, it will leak after adding PG. It changes the viscosity of the fluid. Why it leaks is either poor design or poor packing material.

There, have I sufficiently whizzed everybody off. Just I guys opinion.

George_10

Thanks Drew for the info and the laugh

You haven't raised my angst, in fact your aside made me smile and then laugh. Thanks.

coldupstairs

Drew's responses

The viscosity of propylene or ethylene glycol is greater than water. Increased leaking from a gasket would only be explainable with a LESS viscous fluid substituted for a more viscous one. It must be something other than viscosity.

Aspirin is acetylsalicylic acid. Vineagar is indeed acetic acid. That's why salads don't help with headaches.

The information about inhibitors was enlightening. Anyone who has ever used glycol and had problems must have wondered about why we can't make that stuff work better in hydronic systems, especially when it seems so reliable in a moving, vibrating car or truck engine.

Duncan_13

Gee whiz...

It's better to be whizzed off... I'm just sayin you COULD have, not that you did. You know the deal: it's kind of irritating to hear... "I know the answer, but I'm not tellin. Call me."

Personally, I was lookin forward to the old wive's tales.

Acetic acid is in vinegar. I'm thinkin the way silicone caulk smells, it must have some in it too. Aspirin is acetylsalicylic acid. Burned glycol has glycolic acid, which is used to burn off skin to make it prettier. I think I've seen some of those faces.

How about glycol that doesn't get burned that sits in an airtight system? I'm thinking it must stay OK if there's no evaporation. After all, it's stored in barrels for years. Would the situation be the same in a closed hydronic system? Or does even 190°F heat in a system with good flow eventually degrade it?

Like hot rod, I've seen some NASTY glycol stuff come out of stagnated solar heating systems.

Got a website that explains glycol?

Thanks, Drew.

hr

The best info on glycol

that I have found is this FREE Engineering Guide from Dow. They have one for propylene based and ethylene 1-800-447-4369 should get you one.

Duncan, glycol can be stored in steel drums. Glycol is hygroscopic, so it is important the drum be sealed air tight. Tanks coated with high bake phenolic resins, polypropylene, or polyvinylidine flouride, are recommended for extended storage if the drum is continually opened. I see it shipped in those blue plastic drums also.

Straight glycol or mixes of 80% are in fact flamable, beware of that when using open flame around glycols.

Inhibited glycol should not be used less than 25% as the inhibitors are too weak.

Keep in mind the inhibitors are in there to handle the blend water you add. Ideally the inhibitor package would be matched to the mix ratio you intend to use. Custom glycol blenders will ask you your intended mix ratio, and blend the inhibitors to it.

Clean, oil and dirt free systems are imperative, or the inhibitors are compromised.

Do not use galv fittings, zinc reacts with glycol.

PG and EG glycols can be mixed if the inhibitors are the same. you wouldn't mix automotive glycols with hydronic, for example.

Most automotive glycol is now PG due to toxicity issues. Still not a good idea to use it in hydronic systems, however, the inhibitors will gunm up hydronic components.

Propylene glycol is less viscous than water and tends to leak a lot more than plain water. Ethylene glycol is even less viscous than PG, it is a better heat transfer fluid for this reason. It leaks even more than PG

EG is considered toxis, yet it does break down in the enviroment faster than PG. One less carbon. Usually airports squirt EG, on planes, for this reason, as it breaks down quicker in their bio ponds. Then it can go into public sewer systems.

Drew is right, there is a ton to learn about glycols. I did some reasearch for an RPA article a while back. I managed to get hooked up with a DOW engineer that taught me a lot via phone and e-mail. Still just scratched the surface, however.

The method of cracking glycol from a barrel of crude oil was hard to grasp, considering food grade glycol is a very common food ingrediant for flavor and scent enhancing.

If you work with glycol you really want to get some training materials. Can't believe how much I didn't know about the stuff!

hot rod

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coldupstairs

viscosity of glycol

Sorry, but propylene glycol added to water in any concentration results in a solution that is more viscous than the original water. The viscosity (measured in centipoise units) is highly temperature dependent, but it is always greater than the viscosity of water at the same temperature.

Dow chemical is an excellent source on the physical properties of glycols, see figure 11 (graph of glycol and water viscosities across a wide range of temperatures) in http://www.dow.com/propyleneglycol/about/index.htm
(download-"A Guide to Glycols" at bottom of page to get figure 11)

Glycol in a hydronic system may leak, but its viscosity isn't the reason...in fact whatever the reason is allows it to leak in spite of its higher viscosity.

hr

Correct you are, Lee

about the viscosity.

Maybe it is slippery than plain water? Seems some of the soaps I have used for cleaning hydronic systems over the years "leak" where regular water didn't.

hot rod

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Duncan_14

Other wierdness...

Don't spill it on the pilot lighting instructions sticker on the boiler. The print will disappear.

And what happens to the red dye in CryoTek after it's been in the system a while? Starts out pink, ends up clear. How th...?

You know... I understand how a tiny helium molecule could find a leak that water can't, but I have no idea how propylene glycol can find leaks water can't. Maybe the water leaks too, but just evaporates without a trace, but glycol does the acidity thing and makes blue copper gook?

Weezbo

i severely dislkie the stuff. Mostly my work is new construction and the "Ocasional boiler change out"... The Banks here have some bright idea that the glycol is the only way to guarrantee the system..only thing is it doesnt sink in when we tell them ' you are better off with out it.' so our standard is to put' 50 50 for 50 below.'...propyline glycol is like the only way we travel...it reqires a statement pinned to the wall as it were, thats what is in the system.... now what have i seen? whews.... acidic levels the smell of which burns your eyes...black brown couagulations that look like the creature from the dark lagoon...iv' seen all kinds of mixes of all kinds of anti freeze..ok Where do we get rid of this stuff? its been in there since 68? the manufacturers dis avow any use of thier proudcts in residential housing...heat transfer rates.. yet it always seems comforting that 'well theres glycol in the system.'..they arent all created equal..there have been a veritable spectrum of colours that rival the rainbow..some times iv' added food colouring to the no burst just to watch it curc out the air...or detrmine what is going where in inherited systems,Propyline probably should be flushed out and replaced every 2, 3 years...if you dont change the stuff out then hire someone to check the ph and add chemicals,...only problem is, and this is from a friend i can no longer even find...there are a Bunch of minor technicalities and it gets costly ..the commercial establishments cannot afford not to treat the stuff because of the amount of it in thier systems,...a typical 2400 squarefoot home around here has maybe about 18 gallons in the system,the typical commercial establishment? 100's of gallons.maybe more. radiant has lots of benifits however i am not so sure glycol does. perhaps the worst marraige is old Quest pipe and no oxygen barrier.some of the 3 and 4 inch pipes around the return headers are so fouled up in systems left with no supervision that Digging it out is the only means to begin to remove the rust and mud. such a system i say ,this is so bad flushing it and putting in new boilers and new piping in the boiler room and filling it with water and running it through the system for a few days then flushing it all back out again checking that and then adding new propyline .. some gert 16X16 foot hole in the wall with a coil 100 hp fan speed drive blah blah blah causes more fancy problems in geting temps right flows right the correct mixtures return stradgies 60 below zero with all the good intentions in the world brings a bunch more fancy engineering...i have to say commercial applications glycol is more a necessity than a good idea. frozen slabs ..i wont even install a boiler if there is the least vagarity in the owners mind...this slab gets anti freeze! no more 24 36 hr marathons pumping millions of btus at thermal mass with 650 k btu master heaters..uh uh. well...i hope this was helpful...

hr

Be careful with 50-50 mix, Weezbo

some boiler manufactures, most of the copper tube ones, don't allow that high mix percentage.

If the glycol is checked yearly, and the system is tight it should last a long, long time, 20 years or more. The boost package, even for large systems is not expensive. Especially compared to a drain, flush, and refill.

Dow, Nobel, and others will test the fluid for you. DOW offers free testing service for large capacity systems.

If the glycol continues to go bad, frequently, look for the cause. Non barrier tube, extreme high boiler temperatures, sources of O2 ingress, flow rates through the boiler, bad blend water, etc.

Here is another good link for glycol info.

http://www.paloma@raypak.com/afreeze.htm


hot rod

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jerry scharf

wetting agent

I believe it's called wetting. It's the thing that soapy water spreads out while pure water beads. The greater the wetting factor, the more the fluid will follow tiny pores and find a way out.

Weezbo

would be nice....

to get the banks to listen .... once a system is up and running i think it is better to change the mix so that it is satisfactory for about 10 or 12 below zero..............the thermal mass of the building gives people time to get some on over to change out an aquastat or push the reset or tell them they are out of fuel.

Weezbo

would be nice....

the double click thingy got me,so...we tend to use iron boilers alot as natural gas in our area is a recent development. we see alot of minor technicalities arise from the designes of boilers and various piping arrangements and control stradgies that might not be of concern in warmer climates... maybe, i dont know this for sure, maybe, alaska buys more oil fired boilers for new installs than any other state in the union....just where we will end up on the learning curve with natural gas is a good question...so far i have installed a variety of natural gas boilers.... the flash heaters i have yet to use for anything other than domestic water applications. i honestly do not know what heavy mixtures of anti freeze would do to these systems in a heating application. my feeling is that a storage tank then a heat exchanger off of it would be the safest bet. seperate the anti freeze protection from the boiler and distribution system altogether...

Duncan_13

Glycol applications

Hey Weez, try to cut back on the coffee a little, OK? ;-)

I only use glycol for snowmelt or vacation homes that are vacant for some of the year. If the heat went out, they wouldn't know it for a while. But it only occasionally gets 20 or 30 below here.

It's a pain, plain and simple, the way it finds leaks. But I have to admit, PEX stays milky white in a system with antifreeze containing inhibitors, and turns gray in systems without it.

I gotta tell ya, I really have trouble figuring out the logic:

"..the commercial establishments cannot afford not to treat the stuff because of the amount of it in thier systems,..."

Have they ever priced replacement of a 75HP circulator or a three inch 3- way valve? If anybody should be checking that stuff every year, they should! What the hell are they thinking?

John Abbott

Ineresting....

but useless information.Food grade PG is one of the ingredients in Slush Puppies.

John

Weezbo

let me re iterate ....there have been more than one occasion that i have arrived to find various forms of antifreeze in the soup. True pg is a food suppliment these days however next time you find empty automotive anti freeze containers on the site and a couple left over to top it off or perhaps some get this windshield washer antifreeze ! containers...on an on...Yeah it digresses from the topic a bit however what the Rouge home owner, diy or others of the well intentioned may do when you arent there Watching them is partially what some of our codes are doing in place...even at that, i would not recommend going out and pouring a gallon of food grade pg on my cherrios say ... not even if it had a chance to "Mellow" 30 40 years in a pristine twin meggar caravaned system:).

Mark Eatherton1

Thanks Drew...

BTW, I have seen what appears to be stratification of prop gly/water mixes. Next time I get up to the offending job site, I'll try and get you a photo. It's in a plastic makeup tank, and you can see a definite difference.

ME

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Weezbo

i dont kno....Duncan

i just keep drinking the coffee they give me and fixing it:)))

Duncan_13

Food grade soup

I'm betting you see a LOT more anti freeze in Alaska than we do in the lower 48.

I know what you mean about the soup Weez. What's the freeze point of an "anti-freeze" solution when two or more lines, or no lines show up on the antifreeze refractometer?

I've seen silicone oil mixed with glycol and water, but the windshield washer fluid is a new one on me.

Another good one was a contractor using glycol water to wet his concrete saw. Hey, it looked like a plain old water hose bib! I don't know about you, but I use brass hose bib caps on all glycol hose connections, because they eventually leak.

How food grade can glycol be when there's corrosion inhibitors added?

How do you get rid of a burnt, stanky mixture of unknown antifreeze? That's a rhetorical question, but you can answer if you want to.

Duncan_13

Food grade soup

I'm betting you see a LOT more anti freeze in Alaska than we do in the lower 48.

I know what you mean about the soup Weez. What's the freeze point of an "anti-freeze" solution when two or more lines, or no lines show up on the antifreeze refractometer?

I've seen silicone oil mixed with glycol and water, but the windshield washer fluid is a new one on me. Some of that glop is scary to handle, smell, touch, breathe, or even look at.

Another good one was a contractor using glycol water to wet his concrete saw. Hey, it looked like a plain old water hose bib! I don't know about you, but I use brass hose caps on all glycol hose connections, because they eventually leak.

How food grade can glycol be when there's corrosion inhibitors added? Which there should be, in a heat exchange fluid.

How do you get rid of a burnt, stanky mixture of unknown antifreeze? That's a rhetorical question, but you can answer if you want to.

Duncan_13

You mean

You keep fixing the systems or fixing the coffee? ;-)