Best htf for chiller @ -70

I’m about to order 20+ gallons of dow syltherm xlt for a cryodax 60 and seeing what others are running and possibly better options.

Thank you

Ethanol works great


Just going to say you need to ensure your chiller pump seals and piping/hoses are all compatible with whatever you go with.

Slytherm xlt is silicone based and needs ptfe


Bump cause I’m interested as well

What’s are the option for thermal fluid

Great tip @thesk8nmidget

I use slytherm xlt. It’s tricky to start up with but once you get it dialed it’s fantastic.

You need to ensure there is no moisture in the system and take precautions to remove it. One chiller we have is a pressurized sealed system and the other is not sealed but has a desiccant filter on the tank vent to absorb any moisture that wants to try and get in.


We’re using dynalene HFLO.


Ethanol is great, isopropyl is not as good.

Much cheaper options if you can assure your AHJ that it’s safe…and if it actually is safe…

Either way, low temp HTF is usually flammable.


Would heptane denatured ethanol work just as well?