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Glycol must be at a concentration of >20% says expert

post #1 of 25
Thread Starter 
I've seen a lot of different posts in forums with different concentration suggestions for glycols. It's common to see people say 10% and 15%.

This source says something quite surprising and alarming:
Quote:
Originally Posted by Darrell Hartwick 
In the case of glycol loops, verifying that the glycol concentration is more than 20% is critical. At levels less than this (for chilled and out of service hot loops), rapid biological degradation of either ethylene or propylene glycol to an assortment of organic acids and intermediate products, will take place.

Water Treatment In Closed Systems — ASHRAE Journal

Darrell Hartwick is the technical marketing manager with Eclipse Chemical Company in Baie D’Urfé, Quebec.

link

This is the first I've heard of glycol molecules disintegrating from not having an adequate concentration!
post #2 of 25
Thread Starter 
This explains why EK warns against diluting its coolant concentrate beyond its recommended dilution level. I'd rewrite the warning to say "If you do this your coolant will disintegrate!". Otherwise, people might be tempted.

I wonder how many failures people have had with various coolant mixtures are related to them trying to stretch their dollar and/or get better performance by diluting them too much.

The author defines a hot loop as being at least 140F by the way.
post #3 of 25
Thread Starter 
I was at Micro Center today and discovered a few things:

1) Thermaltake or Thermalright is selling an opaque liquid that says it has like less than 5% ethylene glycol in it. Hmm. Unless there's 15% or more propylene glycol as well this sounds like a recipe for the glycol degrading.

2) The EK premixed EVO coolant uses ethylene glycol.

3) There was a small bottle of green opaque coolant (can't remember the brand) which was also ethylene glycol.

4) There was another brand made with ethylene glycol.

5) The EK concentrates were all the pastel stuff which is made with glycerol rather than a glycol. Apparently this is rebranded Mayhem's. I'm personally not so keen on putting dyes or opaque pigment particles into my system. I also wonder about the effectiveness of glycerol for heat transfer and reduction in corrosion.

EK used to sell Ekoolant which was made with propylene glycol. I would prefer to get one with that instead of toxic ethylene. Does anyone sell a propylene glycol coolant anymore, especially a clear one without dye?
post #4 of 25
Also found this in the article...

"Microbiological monitoring is seldom needed in hot water loops that operate continuously above 140°F (60°C) or in chilled systems where the glycol concentration is above 20%"

The article also mentions adding a pH buffering chemecal to make sure you properly manage corrosion.

"Ortho phosphate, typically dipotassium phosphate (or adjusted mixtures of di- and tripotassium phosphate) can be used to control the pH between 9 to 10.5"

This article implies an all metal loop, I have no idea how these chemicals at high levels react to plastics and acrylics at such *high* levels. Maybe someone else can answer that.
post #5 of 25
Thread Starter 
Quote:
Originally Posted by kl6mk6 View Post

The article also mentions adding a pH buffering chemecal to make sure you properly manage corrosion.
Yes, most everything I've read says that an elevated pH is important (or at least not more acidic than fresh distilled water) to a point. Too high a pH may be an issue, though, with some inhibitors.
Quote:
Originally Posted by kl6mk6 View Post

This article implies an all metal loop, I have no idea how these chemicals at high levels react to plastics and acrylics at such *high* levels. Maybe someone else can answer that.
It's a good question. Also, phosphates could potentially precipitate out I think. I've read so much and it's so late that my mind is getting foggy about the details.

As for pH, I found this very interesting nugget about kill coils:
Quote:
Copper and Silver Ionization

Ionization indicates the electrolytic generation of copper and silver ions in cooling tower water. If properly managed, copper and silver ion concentrations at 20 to 30 µg/L and 10 to 15 µg/L,respectively, can be effective to kill bacteria in the systems. The ions assist in the control of bacterial populations in the presence of a free chlorine residual of at least 0.2 mg/kg. It should be noted that in hard water systems, silver ion concentrations is difficult to maintain due to build-up of scale on the electrodes, and the high concentration of dissolved solids precipitating the silver ions out of solution. For both hard and soft water, the ionization process is pH sensitive and it is difficult to maintain silver ion concentrations above pH 7.6. It is not recommended to adopt ionization in systems having steel or aluminum heat exchanger since deposition of the copper ion and subsequent galvanic corrosion is significant.

http://www.slideshare.net/munawarbashir/cooling-water-problems-and-solutions

So, that suggests that not only are the elevated pH solutions bad with a kill coil, a kill coil may be a bad move when using a steel jet plate. This supports EK's claim that a kill coil with distilled water isn't safe for galvanic corrosion, making me wonder if the use of steel jet plates is designed to sell expensive coolant.

However, a heat exchanger in that context might be a higher temperature than what we're dealing with. Things that are okay for corrosion sometimes become a corrosion hazard at high temperatures. I saw a book today that showed some chemicals are only corrosive with some metals when they're in the molten state.

The bit about chlorine is also interesting, particularly since I don't see many recommendations for putting bleach into a loop.
Edited by superstition222 - 10/3/16 at 10:47pm
post #6 of 25
Yup, EK specifically stated they don't recommend kill coils in loops with their products (or in general) without a good corossion inhibiter.

"Refrain from using strips of Silver (Ag), also known as “Kill Coil”, with distilled water alone in your water cooling loop. Besides introducing another metal into the already mixed-metal loop with no corrosion protection, the concentration of Silver ions may not be enough to prevent or to suppress biological growth in the liquid cooling loop."

Source
post #7 of 25
Thread Starter 
If not for the iron jet plate, the pH requirement doesn't seem to be a big deal if you're just running distilled water and small quantities of azole corrosion inhibitors (so long as they can function around a 7 pH — like benzotriazole/BTA) but the free chlorine clause is concerning. How is someone relying on a kill coil going to get free chlorine in their loop without problems from it?

Why aren't there copper jet plates or some other metal? Bronze? Brass?

I guess it's helpful to sell expensive coolant. If you don't your system may corrode badly.

I've also read so many people in forums suggesting that more frequent changes of water help reduce corrosion but, today, I read exactly the opposite. Some people claimed that changing the water frequently accelerates corrosion. I'll have to try to find some actual data on that — since so much forum advice is spurious.
Edited by superstition222 - 10/3/16 at 11:17pm
post #8 of 25
@superstition222 why all the deep research? Just pick one poor it in thumb.gif It's not a coral reef smile.gif
post #9 of 25
Thread Starter 
Quote:
Originally Posted by geox19 View Post

@superstition222 why all the deep research? Just pick one poor it in thumb.gif It's not a coral reef smile.gif
Name me a colorless clear one that's made with >20% propylene glycol and which protects from galvanic corrosion involving steel + copper + nickle + solder and I will.

EK's that was formulated that way was end-of-lifed, by the way.
post #10 of 25
Quote:
Originally Posted by superstition222 View Post

Name me a colorless clear one that's made with >20% propylene glycol and which protects from galvanic corrosion involving steel + copper + nickle + solder and I will.

EK's that was formulated that way was end-of-lifed, by the way.

Exactly...That's why I say just pick one and throw it in because there's nothing out there clear or colored that's going to protect you 100% from Galvanic corrosion. All these water block manufactures can say what they want any time you mix different metals especially plated metals there's a chance there's going to be corrosion or the plating just falls off because they do a crap job on the metal plating. I guess you could get distilled water and throw some zinc blocks in your res. Works for my boat.
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