Outdoor Boiler Antifreeze

Do any of you guys run antifreeze in your outdoor boiler? It seems like a pretty big initial investment and I understand it may use a little more wood to get the water / antifreeze mixture up to temp.
It would be nice to be away for a week or two in the winter and not have to pester a neighbor to tend the stove for me.
I had heard that you can let the fire go out for a period of time and the pump circulating the water into the basement and through the indoor furnace will not allow it to freeze.
I am a little skeptical on that when it could be -20 outside. If we have a bad winter storm and the power is out for a few days is a concern also.
Just looking at not being completely dependent on wood heat from November to April.

Thanks, Zim

Zim a lot of people do up here particularly if they are heating out buildings.

Osky

So you don't have a back up furnace that runs on gas.

That!

With a backup furnace an unattended boiler's water will pick up enough heat from the heat exchanger(s) in the house to be safe. Mine maintains 80°F even though it also serves an otherwise unheated solarium and three car garage.

Beav and T-Rex, either I need to improve on my writing skills or you fellers .. ah never mind.
T-Rex how does that work when your electricity is out?

Zim

We use propylene glycol in lots of cooling towers that are exposed to the weather over the winter. These often share water with boilers so it's perfectly normal to run glycol through a boiler.

T-rex is correct, if your circulating pump is running, you are pumping water warmed by the house out to your heater. Whether that is enough heat depends on your pump and exchanger. We lost a $40,000 tube bundle heat exchanger in a cooling tower last year when a pump failed overnight. That system now has glycol.

I don't know if glycol takes longer to heat than water or not. But, if glycol does require more heat input to come up to temperature, it won't be much and it doesn't matter anyway because it would then have more heat available in the glycol to heat the house.

The one issue you do have with glycol is it makes the water more viscous. Pumps can push less fluid as the percentage of glycol increases. It seems that everything works pretty good until your glycol gets close to 20% - your setup might be different.

And, we use propylene glycol instead of ethylene glycol. Propylene is "food safe" according to the FDA. Ethylene is poisonous. We also have the water treatment company add dye to the system when we add glycol. Heating water - red. cooling water - blue. This way, we know right away if a leaking pipe is heating water, cooling water, or just regular water.

Thank you, That is the kind of stuff I was hoping to hear.

Zim

So with no gas back up when you leave your going to have to drain your potable water systems and add antifreeze to your drains and toilet.

No Beav, as my original post says I was questioning if the pump would allow the water circulation to the basement furnace to keep from freezing when it is really cold.
T-Rex says he thinks so. Mighty expensive deal if it doesn't. The outdoor boiler system has a temperature switch connected to the propane furnace in the basement.
If the water temp. coming from the outdoor boiler for any reason falls below 140 degrees the LP furnace kicks in.
Happy Holidays to ya.

Zim

Well here's what I would do If you plan on leaving for a week or so. Install a holding tank In your basement then when you leave just circulate the water through the tank and by pass the out side boiler.l

Hey, that makes good sense.

Thanks, Zim

I turn my boiler temp down when i leave and stack it full of wood. Turn the house temp down to 55.
I get at least 3 days that way.
Then i turn my forced air furnace to 50. This keeps my outdoor boiler good as long as the breaker doesn't pop or power goes out.
Safest way is with antifreeze in lines. I have not gone that way yet.
One big freeze up and antifreeze would pay for itself easy.

I bought used antifreeze from the local junkyard and it has worked fine for years. They have to drain it from the vehicles before they can scrap them. Has to be properly disposed of so they sell it dirt cheap-here at least.

If those that have Outside wood boilers would build the pipe chase correctly they wouldn't have to worry about antifreeze and there water freezing up. A well Insulated chase and some heat tape wrapped around the pipe Is good insurance.

I hate heat tape. I've had it fail too often to trust it.

Yes but It's better then NO heat tape.

I thought that boiler antifreeze was really concentrated and you didn't use as much. How many gallon is your system?

Zim,
I've had anti freeze in my boiler for over ten years, the lines are inside an insulated pipe, and buried 5 feet underground. Replacing broken lines in December sucks. If my power drops from a major snow storm or a leak has to be fixed in the system I don't worry anymore. Cheap insurance in my mind.

Thank you Rally for your input. My lines run from the outdoor boiler thru an insulated pex line also.
Do you recall if you bought a specific brand of antifreeze?I
I was hoping to get by with a 55 gallon barrel of the stuff.

Thanks again, Zim

196 gallons.

Zim

Check your insurance agent; especially what anti freeze you use; and the types of pipes from the burner, seems to me there has to be 5 feet of metal pipe so a fire does not travel down the line.
All it took was one house burning down for them to cover their buttocks.
Wiring should be so you flip and switch and plug in a generator to run the pump.
Sale of property is a night mare with a outdoor stove especially with what anti freeze you use, so keep some records of purchases of the anti freeze.
You have to prove what went in comes out , it is all about ground water contamination of a leak.

I do this also stomper. If I get a running start and jam the stove full of good oak it will hold a fire for 48 hours if the indoor
Thermostat is set to 50 and the outside temp stays above zero.

Zim

The anti-freeze is also excellent corrosion prevention too.

Propylene glycol is the antifreeze used in boilers as long as it doesn’t have a aluminum heat exchanger . Aluminum requires a special antifreeze and additive. Another thing is you must test the strength of your boiler waters antifreeze ever year it weakens over time and must be added to. If not checking the antifreeze strength you will wish you had.

Zim I can come over and fill your stove for you while your gone.

While your at it you might as well eat up all those Ontario walleye in the freezer , just wrap the packages back up with a block of same size ice cube after consumption.....with the real FREEZER BURN STRIKES on the label.

I never knew people ran outside boilers without antifreeze??? Not only does it keep pipes from freezing but it inhibits rust and lubricates the pump.

North of 50 good idea

I had an outdoor wood boiler for over 30 years. I never ran anti-freeze in it or anti-rust chemicals. My stove was stainless steel, so rust wasn't a problem. We did have a forced air furnace as back up in the house that was fueled by propane. If we left for a longer period of time, we turned the furnace on. With the wood boiler's pump circulating the water, we never had a problem with freezing while we were gone.

Check your insurance for extended periods when you are not home....most clauses require a 48 or 72 hour check......and the outdoor stove is high on that list.

black and tan just don't post any pictures of What's for Dinner, cause Zim knows where I live, those Surveyors can find a lot of things...sometimes

Lol my plate would never look as good as what Zim and Patrice put on a plate