Automotive anti-freeze for a residential steam boiler?

Double D

Has anyone ever heard of a residential steam boiler with automotive anti-freeze in it? I'm on a job now that I need to build a false water line and when I went to drain the boiler, it had anti-freeze in it. There is a wet return exposed in the attached garage but the garage is heated. You never know what you'll find out there.

Jamie Hall

I can't think that that was working all that well, somehow... though of course the stuff does boil, albeit at a significantly higher temperature...

JUGHNE

Somehow I can see more fuel to boil it at a higher temp and then foam production.??

ChrisJ

Are you sure it's anti-freeze?

Double D

I'm sure it's anti-freeze. I'm dealing with the new owners who just moved in May 2nd. Possibly the previous owner had it done or did it himself while the house was on the market over the winter. He spends a couple months a year in Florida. The new owners originally just wanted to take the rads to have them sandblasted. When I came to look the job over, they mentioned the banging, that's when I noticed the water fell out of the wet return.
I smelled it when I was skimming but didn't think anti-freeze right away. When I drained the boiler I still noticed the smell but still didn't think anything of it. As I went around disconnecting radiators, the remaining water had a greenish color to it. At that time I was thinking "is his anti-freeze?" So I has a sample tested.

With a wet return passing through a heated garage, I think the only advice I would give them is don't try any deep setbacks in single digit weather.

Sound about right?

pecmsg

Auto antifreeze contains silicone to coat the inside if the engine, not a good idea in a boiler, piping and rads!

Also not good for the environment when spilled.

Good luck getting it out, the damage is done.

ChrisJ

pecmsg said:

Auto antifreeze contains silicone to coat the inside if the engine, not a good idea in a boiler, piping and rads!

Also not good for the environment when spilled.

Good luck getting it out, the damage is done.

Older antifreezes contain silicates, which come from silicon, I don't think it's related to silicone at all though. More like sand.

More modern antifreezes not only do not contain silicone, but will even attack it.

You are correct though, they are designed to coat things to protect them but I'm not sure how much damage this would do to a heating system. I will admit I have no plans on finding out and am glad it's not my system. Chances are it can be fixed though.

Hell, for all we know that boiler will work fine and outlast all of us because of it.

Jamie Hall

Chances are that no permanent damage has been done to anything, oddly enough. The anti-corrosion coating, if any, won't have hurt the heat transfer from the steam to the radiators or, for that matter, have hurt the boiler much, if any. As @ChrisJ said -- the whole thing may even last longer!

Repipe it so it's correct and carry on. And while you're at it, can you arrange things so that that wet return in the garage can be isolated and drained if the system is to be shut down for any length of time?