Hydronic radiant heat - glycol

[anwalt]

Gents:

I am working on completing the radiant heat for my garage -- -- er "shop".  Freeze proof fluid is necessary.  Looking at the price of propylene glycol from HVAC suppliers makes me consider other, and more convenient, sources.  

Is automobile ethylene glycol suitable for closed loop radiant heat use?  Vehicle coolant contacts copper (thermostat), polymer (water pump impeller), rubber hoses.  

If not ethylene glycol, then how about propylene glycol RV antifreeze?  

My pumps (circulating and blending) will be stainless with polymer impeller. I am thinking the highest risk item in a closed loop system is the membrane of the expansion tank.  

Interest in the thoughts and experience of others.  

thx,
Tom

[woodhead]

What you need:

https://www.supplyhouse.com/Hercules-352...l-5-Gallon


How many gallons in the system and low temp to withstand???


Al

[anwalt]

What you need:

https://www.supplyhouse.com/Hercules-352...l-5-Gallon


How many gallons in the system and low temp to withstand???


Al

Al,  
Need 6 - 7 gallons of 30%glycol

Don't have a ready use for the balance of 5 gal pail.  

tom

[woodhead]

Al,  
Need 6 - 7 gallons of 30%glycol

Don't have a ready use for the balance of 5 gal pail.  

tom

1 gallon size

[Bluepine]

Al,  
Need 6 - 7 gallons of 30%glycol

Don't have a ready use for the balance of 5 gal pail.  

tom

With a closed loop system you will be adding glycol every year to keep the system topped off. Buy the 5 gallon bucket you will eventually use it up.
What kind of boiler are you using?
https://www.menards.com/main/heating-coo...936181.htm
This is what I used in both my shop and my house although I bought full strength.

[BloomingtonMike]

I used the cryotek 100 5gal mixed 55:45. I ordered mine during a 20% off and free shipping from zoro. The amount i have added each year to my sealed setup is very little.

[blackhat]

Buy the hydronic blended.  Its made for the job.  Make your mix about 35% glycol and get it tested annually by a lab.  Low percentages and low temps can cause breakdown or biological growth.  Cleaning up a bio mess or acidic breakdown can be expensive and a lot of work.