Boiler Antifreeze

[Sumboodie]

Anyone smart about this stuff?

What's special about boiler antifreeze like TriaFrost, DowFrost, etc... at $25 a gallon that normal ELC antifreeze at $9 can't do?

Don't care that it's ethylene glycol vs propylene.

I'm sorting out a waste oil boiler that'll be in a shed. Tied to the main heat system on a heat exchanger.

Plan to just keep it on, old school style where it holds 160-180 regardless of call for heat or not. It's an older 85% efficient cast iron boiler.

But in case of shut down or power loss, it could end up freezing.


Reading online the usual it'll kill busloads of nuns or been using it 700 years without issues.

 

[Lassen Forge]

We had some soluble oil + special anti-freeze mixture in ours, but it was (honestly) more for corrosion resistance than anti freeze. Boiler antifreeze can handle both direct heating as well as low temps, and may also have lubricating properties for the circulation pumps... the main thing is it won't break down when heated by temps generated by flame impingement. We don't worry too much about freezing 10 months out of the year, and the other 2, we keep the system set above 10C (50F) so it never gets that cold.

The biggie is the heating system the boiler is attached to - if you have aluminum radiators, you don't want something that will corrode them out. We JUST replaced the main radiator in our kitchen over this, and are looking at having to do the one on the top floor as well.

Reading online the usual it'll kill busloads of nuns or been using it 700 years without issues.

Or they've been using it for 700 years to kill busloads of nuns without issues...

 

[Sumboodie]

We had some soluble oil + special anti-freeze mixture in ours, but it was (honestly) more for corrosion resistance than anti freeze. Boiler antifreeze can handle both direct heating as well as low temps, and may also have lubricating properties for the circulation pumps... the main thing is it won't break down when heated by temps generated by flame impingement. We don't worry too much about freezing 10 months out of the year, and the other 2, we keep the system set above 10C (50F) so it never gets that cold.

The biggie is the heating system the boiler is attached to - if you have aluminum radiators, you don't want something that will corrode them out. We JUST replaced the main radiator in our kitchen over this, and are looking at having to do the one on the top floor as well.




Or they've been using it for 700 years to kill busloads of nuns without issues...

Cast iron, copper, pex and stainless. And plan to drain and refill every year or two.

 

[Lassen Forge]

You also have to watch out for galvanic corrosion between dissimilar metals - You have copper, CI, and Stainless... if they're in contact with each other, you run the risk of Electolysis. Pex would make a good breaker. Used to use brass between galvy and copper because they were closer galvanically (see the chart below).

First house me & the other half bought, someone used a hunk of black iron pipe in our hot water system to directly connect with the copper hot water piping in the house - lasted a few years, then we got to test our basement sump pump the hard way... oops.

Nothing ***** worse than having your hot water stop in the middle of a shower, but you still hear the water running full tilt.

Anyway, this tells you just how dissimilar the different galvanic metals are - like I said, plastics will break this, but can also break down under heat. If you use "hot" (red) pex that will break your galvanic action.

THE GALVANIC SERIES CHART:
When any two metals in this list are in contact, with an electrolytic present, the one with the lower number is corroded. The galvanic action increases as the metals are farther apart in the Galvanic Series.

1. Aluminum
2. Zinc
3. Steel
4. Iron
5. Nickel
6. Stainless Steel 400 Series
7. Tin
8. Lead
9. Brass
10. Copper
11. Bronze
12. Stainless Steel 300 Series

 

[Sumboodie]

I had nothing but headaches with those dielectric unions on my previous house's boiler.

I'll deal with it rotting out instead.

 

[American Locomotive]

Regular automotive antifreeze has to deal with mixed metals and high temps as well. They have lots of corrosion inhibitors.

I think the biggest difference is the propylene base vs etheylene. That's even more important if your boiler is connected to your potable water supply for makeup water.

 

[Sumboodie]

Regular automotive antifreeze has to deal with mixed metals and high temps as well. They have lots of corrosion inhibitors.

I think the biggest difference is the propylene base vs etheylene. That's even more important if your boiler is connected to your potable water supply for makeup water.

It's not, have to fill with a pump