Vacation freeze prevention

[Tony H]

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.

 

[sgrenier35]

You don't need to run heated water to your " outdoor " boiler just keep the circ running/ water moving and the water will never freeze. This is how most owb's are plumbed also for freeze protection.

 

[Northwoodsman]

The RK2001 controller has a saftey feature built in which turns on its circulating pump if the temp. goes below 40 F.

NWM

 

[taxidermist]

The RK2001 controller has a saftey feature built in which turns on its circulating pump if the temp. goes below 40 F.

NWM

Remember all this will do is circulate the water around your boiler if you have your protection loop open. You still need to bypass the termovar to circulate water from your storage to the boiler and back. I did this last year I only circulated the boiler and the pex froze where it comes up out of the floor.


Rob

 

[Hunderliggur]

Per Mark's suggestion at AHONA, I drilled a 1/8" hole in my Danfoss "disc" to allow water to flow even when the Danfoss valve is not open. I had an issue with the non-boiler lines freezing before the boiler reahes 40F. I have heavily insulated the lines from the boiler to the underground and have not had another problem.

 

[Tony H]

You don't need to run heated water to your " outdoor " boiler just keep the circ running/ water moving and the water will never freeze. This is how most owb's are plumbed also for freeze protection.

The boiler shed is uninsulated with insulation on the pipes only. The water is heated only because it runs thru the HX in the furnace plenum.

 

[Tony H]

The RK2001 controller has a saftey feature built in which turns on its circulating pump if the temp. goes below 40 F.

NWM

Remember all this will do is circulate the water around your boiler if you have your protection loop open. You still need to bypass the termovar to circulate water from your storage to the boiler and back. I did this last year I only circulated the boiler and the pex froze where it comes up out of the floor.


Rob

Do both models of the controller have this feature ? I have the older unit with fewer features and temp reading in celcius.

 

[taxidermist]

Not sure Tony if yours does might have to ask Zennon about that. I also hooked up anpther power lead to my pump with a celing fan switch. I can start the flow of water before the boiler cools to 40* I dont want to ever freeze my pex at the boiler again as this was a nightmare.

Rob

 

[Tony H]

Not sure Tony if yours does might have to ask Zennon about that. I also hooked up anpther power lead to my pump with a celing fan switch. I can start the flow of water before the boiler cools to 40* I dont want to ever freeze my pex at the boiler again as this was a nightmare.

Rob

Sounds like a nightmare I can live without. I have a pair of switches to allow EKO's controller to signal the pump or to connect 120VAC to the pump directly so it can run anytime and I also have a bypass with valve to allow water flow around the termovar so it will circulate thru the entire system. I used it last week when I was on a trip and it worked great.
I agree with you Rob 40F is too close to freezing for me I prefer a larger margin for error like 50 or 60 to get water flowing.