which brand of antifreeze for hydronic heater

[maine-cruiser]

Hi all,
I'm currently installing a diesel hydronic heater in my boat and was curious what type of propylene glycol antifreeze anyone is using in their hydronic system. I was probably just going to go with the West Marine -60º F PG antifreeze which states that it has corrosion inhibitors in it. I use it for winterization already. The boat is in the NE US from Maine to Boston if it matters.

Thanks,
Bill

[s/v Jedi]

Originally Posted by maine-cruiser

Hi all,
I'm currently installing a diesel hydronic heater in my boat and was curious what type of propylene glycol antifreeze anyone is using in their hydronic system. I was probably just going to go with the West Marine -60º F PG antifreeze which states that it has corrosion inhibitors in it. I use it for winterization already. The boat is in the NE US from Maine to Boston if it matters.

Thanks,
Bill

The manual should state what you need. The last unit I had was an AquaHot and it wanted a “boiler fluid”, not just an anti freeze. It was sold in gallon bottles at I believe Camping World.

[thinwater]

Actually, what you need is normally called "heat transfer fluid."


https://www.dow.com/en-us/pdp.dowfro....html#overview


In a former life I formulated these. Dowfrost is a typical example. Dowtherm SR1 if you don't mind using EG (if it is not connected to the potable water system in any way).



The problem with engine coolant is that they are only formulated to remain bug-free if they are sterilized by running the engine up to temperature once in a while. Engine coolant can go septic and acid.



I'd consult the manual, because the best choice depends on the metals used.

[maine-cruiser]

These heaters are generally used in vehicles and are plumbed directly into the engine coolant loop. Eberspacher does sell into the Marine market but their manual is rather ambiguous:
" The coolant liquid must contain at least 40%
antifreeze all year round as corrosion protection
antifreeze"
I did see the heat transfer fluid at camper world and other RV sites. They are all propylene glycol based with corrosion inhibitors. The SDS only mentions the PG, nothing about other additives. Just hoping to see if others out there have experience with a particular brand.
There's this brand from Supplyhouse that also looks decent: https://www.supplyhouse.com/Hercules...s&gad_source=1

Thank you for the replies