[mikegoubeaux]

Thanks - very helpful info.

That is the difference in goals for me - I don't want the glycol to be that hot when it is just for freeze protection.

I am hoping to run it to a trailer when it is connected to the vehicle, and those temperatures would be too dangerous for that use, as well as some other uses.

My goal would be glycol / coolant temperatures more like 20 - 30 F above the air temp setpoint.

I see. One idea would be to use a bi-metal mixing valve to temper the glycol (as the Rixen’s system already does to regulate floor temp)—though that it is for a fixed temp, not a delta to air temp. There’s also the issue that in the floor setup, you are tempering with spent glycol, not necessarily cold glycol. But this does help regulate the floor temp.

This valve’s hot input is on the output of one of the glycol reservoir ports with the cold input coming from the loop’s return, this helps regulate the glycol flowing through the floor, and in your case could help regulate glycol running to your trailer etc.

You could also create a custom solution with a temp sensor and some sort of controllable valve to create the exact ambient + X temp you’re looking for.

The furnace heats glycol to a set range, I don’t believe that’s something you can override. You’ll likely have to manage the glycol mixture to create the temp you want.