Having seen this topic discussed before but never read about actual use and so I decided to test the application. I have a boiler installed in a shed about 75' from the house with buried pipe to an HX installed in a gas forced air furnace with DHW attached. The idea is by running the water thru the system when the boiler is off can you warm the water to prevent freezing without using glycol for protection.
I have glycol in the system but found when I had the system off for a day to do a door repair that the liquid in the boiler will indeed freeze and with an upcoming trip wanted to check on an alternative. I installed a pair of switchs to allow the pump to be powered by the EKO or powered by direct AC power then I installed a bypass with valve to allow water to bypass the termovar valve.
I shut the boiler down for a test and had the backup thermo set at 65F to see what happens. After cooling for a while the temp gauges all read about 65 degrees and all appeared well a few days later I left on my trip and set the temp on the forced air furnace at 55F and after 10 days when I returned the temp gauges read about 57F and everything was good I fired the boiler back up closed the bypass and went back to EKO control of the pump and all is fine.
This confirms the idea you do not have to run glycol to prevent freezing in your outdoor located EKO 40 boiler or models with similar amounts of water in the system.
I have glycol in the system but found when I had the system off for a day to do a door repair that the liquid in the boiler will indeed freeze and with an upcoming trip wanted to check on an alternative. I installed a pair of switchs to allow the pump to be powered by the EKO or powered by direct AC power then I installed a bypass with valve to allow water to bypass the termovar valve.
I shut the boiler down for a test and had the backup thermo set at 65F to see what happens. After cooling for a while the temp gauges all read about 65 degrees and all appeared well a few days later I left on my trip and set the temp on the forced air furnace at 55F and after 10 days when I returned the temp gauges read about 57F and everything was good I fired the boiler back up closed the bypass and went back to EKO control of the pump and all is fine.
This confirms the idea you do not have to run glycol to prevent freezing in your outdoor located EKO 40 boiler or models with similar amounts of water in the system.