Homemade outdoor boiler controls.

[Joe Hillmann]

The natural gas furnace inside the house isn't a boiler, it is a forced air system.  I plan to put a heat exchanger in the plenum of the furnace and plumb the outdoor boiler to the heat exchanger.  I will then use the blower on the furnace to move the heat through the building.

My system is set up the same way. Like thecfarm, I run my pump through the h/x nonstop.  My pump uses about the same electricity as Hilltops... maybe $10.00 a month.

I have no firsthand experience with using automotive antifreeze, but over the last few years of studying boiler setups, I've read many negative comments on using it.

I've been away for the last week so just read your response today.  What are the problems you have heard of with using antifreeze?

[tractorman44]

The natural gas furnace inside the house isn't a boiler, it is a forced air system.  I plan to put a heat exchanger in the plenum of the furnace and plumb the outdoor boiler to the heat exchanger.  I will then use the blower on the furnace to move the heat through the building.

My system is set up the same way. Like thecfarm, I run my pump through the h/x nonstop.  My pump uses about the same electricity as Hilltops... maybe $10.00 a month.

I have no firsthand experience with using automotive antifreeze, but over the last few years of studying boiler setups, I've read many negative comments on using it.

I've been away for the last week so just read your response today.  What are the problems you have heard of with using antifreeze?

Ethylene Glycol (anti-freeze) is harmful to the environment and lethal to small animals.  Propylene Glycol is environmentally friendly.  There are different "inhibitors" added to anti-freeze used in automobiles than what is added to the glycol used in boilers.  I don't know just what that difference is though.  I also don't think there is any difference in the ability to transfer heat.  I may stand corrected on that if someone has specific knowledge on the subject.

[doctorb]

Actually, the issue of antifreeze has been discussed on a few occasions.  her's but one of the threads:

https://forestryforum.com/board/index.php/topic,59035.msg1117526.html#msg1117526

[itzallbtu]

The other, thus far unmentioned advantage of the circulator pump running constantly is that you are able to use convection heating in the house for a good ways into the heating season.  Essentially, this means that the heat rising off the flat coil in the furnace plenum provides a nice source of heat to the house while the cold air sinks back to the furnace.  Here in MN, I'm able to usually run to almost December without the thermostat calling for the fan to assist.  Keep the pump running and you'll be happier and the equipment will last longer.

73

b