glycol

Rich L.

In our commercial, industrial applications we normally do between 30 to 35% glycol. If we get slush in a system at bitter cold temps (-25* f) that's ok, what we're really looking for is pipe burst protection.

Rich L

dmy hvac

glycol

i installed glycol in a residential crown boiler about 2 weeks ago.i filled it to about 90%glycol 10%water since then the relief has released 4 times once the first night then bout once every 3 days filling a 5 gallon bucket only about a 1/16 of the way i had installed a new reliefe valve at the same time as i put in the glycol cause old one was corroded it is exact replacement so i know its right size.i got responses that glycol can possibly build more pressure than water and i should possibly install a bigger expansion tank i was also told 90%glycol was to harsh if so i was wondering what the right mixture is and if anyone has had this problem before with the reliefe valve after installing glycol.and any other things i can look into to find cause of nusent problem and sorry bout my spelling.thanks any help is greatly appreciated

kevin coppinger_4

I hate glycol...

I avoid it in all cases. 50% should give you plenty of protection. By adding glycol (esp 90%) you indeed would most likely have to upsize your extrol tank...also may have to change up to a larger circulator since it is harder to pump than good ol' water. Furthermore before adding glycol the system should be cleaned to allow a decent lifetime of the glycol. All the contaminants in the system will kill the O2 inhibitors inthe glycol which is what keeps the gylcol crap from eating away your system components.....kpc

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Rob Blair

90% is extremely high, if that is what you put in it. Do you have a refractometer to check the level? To put that amount you would have had to be using 100% and mixing down. Is that what you did or are you using a premixed amount and diluting it to the 90/10 mix. What type of glycol are you using?

Rob

Doug_7

Freezing Point vs. Glycol Concentration

The freezing point of a glycol-water anti-freeze solution depends on the concentration of glycol in the solution, and actually rises when the ratio of antifreeze to water exceeds 60%.

Pure glycol offers poor freeze protection. Pure glycol will freeze at -10 degrees F offering little freeze protection. You want to be in the 50% - 60% glycol range for maximum freeze protection.

http://www.gi.alaska.edu/ScienceForum/ASF6/680.html

You want to use propylene glycol (non-toxic) rather than ethylene glycol (toxic). Never use automotive antifreeze because it is toxic and contains inhibitors that will crud-up your system.

Because glycol is much harder to pump and heat that water, use the lowest glycol concentration possible consistent with your freeze point requirements. Suggest 40-50% glycol unless your climate is severe.

Doug

Doug_7

Freeze point of Propylene Glycol solutions

Attached is the Freeze-point of Propylene Glycol solutions.

Doug

mark_101

% glycol

many boiler manufacturers recommend no more than a 50% mixture. low water cut-offs etc. also recommend no more than a 50% mixture. glycol seems to be a damn if you do damn if you dont situation especially with pro press fittings. why did you decide upon a 90% solution.

[Deleted User]

Caution...

Not all glycols are the same. Some are already pre cut. So, if you put 90% of 50% premix glycol in, then your actual glycnoids would be around 45%. (.5 X .9).

Glycnoid makers recommend a minimum of 30% by pure percentage to insure proper corrosion inhibition. Going wiht less can create more problems on the corosion side than nothing at all...

Been there seen that, saw steel panel radiators springing pin hole leaks due to inadvertent dillution...

Glycol ONLY where absoultely necessary.

ME

Drew_2

Propylene Antifreeze

Just thought I'd clearup some of the response you received about propylene glycol as an antifreeze.
- Propylene glycol does not eat your system. It's a lot like not changing your oil in your truck. If you leave it in your system past its usefull life its biprouduct does harm. This is usually a case of not maintaining the system or like never checking your oil.

- The freezing point of propylene glycol never is greater than -60F and this is achieved @ 59.9% concentration. The freeze point does not go down when the concentration is above this point.

- The thermal transfer rate @ 20% propylene glycol is .97 and @ 50% is .90 . That said, most systems in the N.E. U.S. is at 35% propylene glycol which is about .94 . In other words a 6% loss in thermal transfer with freeze protection @0 and burst temp @ -60 .

Hope this helps.

scott markle_2

70%

Cryo-tec 100 is 70% solution out of the can. I heard that under 20% solution can feed bacteria. Corrosion inhibitors can be added according to dilution, At least this is the way Rhomar does it. Are you sure about 30% being the low end limit, I recall this number as also being a high limit for certain components (propress o rings) this doesn't give much latitude.

ALH_4

?

I have never heard that term before and Google turns up nothing. What is a glycnoid?

Drew_2

Propress/Glycol

I've attached the compatibility page from Viega/Propress' website. According to it you can use 50% propylene glycol with their product.

Doug_7

Glycnoid

Ethylene glycol (monoethylene glycol (MEG) is a glycol made by reacting water and ethylene oxide. Propylene glycol (PEG) is a glycol made by reacting water and proylene oxide. Both are used to make antifreeze solutions. PEG is non-toxic.

Glycnoid is just a made-up word.

Wevzdmsp

glycol percentage

It is our understanding that a 60% ethylene or propylene glycol solution offers the maximum freeze protection. If you go beyond that you are actually degrading it's ability to not slush as well as its ability to transfer heat. If you have an application where you have to maintain a non slushing condition below -60F you should continuously circulate.