My father shuts down his heating system for 5 months thru the winter and goes to Fla. The domestic system is drained and blown out and the traps have prestone in them. Now for the Question ...The heating system has cryotec anti freeze in it, how long is this good for considering its basicaly a sealed system? and Why can't auto type antiferrze be used in these systems?

 

Automotive antifreeze is Ethylene Glycol and is a deadly poison. Injestion will destroy your kidneys and kill you. It also tastes sweet, and any leaks can attract pets. Automotive type antifreezes should NEVER be used in ANY piping--closed loop, open loop, traps--in a home. NEVER. Every manual that comes with a boiler warns against the practice. Even though it is a closed loop system, the remote chance of backflow is still there. It is a poison and doesn't belong in any piping in a home. Any RV store or big box home store can supply the proper antifreeze, and it is cheap.

The proper material is inhibited Propylene Glycol. Glycol can break down over time and become acidic, so yearly testing of the boiler water is a good practice. Glycol will also find any potential leaks in the system, so you might expect to see leakage at seals, pipe joints, etc. that weren't obvious before the antifreeze was added.

 

So from what you have said the only reason not to use ethylene glycol is because it is poison. I'm not making light of this but are there any other reasons. I'm sure the inhibited propylene glycol isn't good for you either.

 

Not to make heavy of it but what r/c said above is some of the best advice, clearly given, that I've seen given here in quite a while.

As for other reasons, yes. The automotive stuff, IIRC, has a bunch of other constituents in it that are potentially quite reactive with the components of the heating system and could lead to corrosion, pitting and premature parts failure.

The right stuff is cheap and readily available. Use it.

And no, inhibited propylene glycol is not bad. In fact, it has sufficiently low chronic and acute toxicity that it is considered non-toxic, although I believe the FDA has not officially set a maximum intake standard.

 

I don't think he should be using Prestone in the plumbing traps either...
on a septic system it could cause problems with the septic tank, and on a sewer system... well, it's a poison that you shouldn't be sending to the treatment plant. Use RV anti-freeze for this.

I think regular anti-freeze will attack the seals and components in the boiler. Didn't PeTe say that ?

Don't do it. Be responsible and do the right thing.

 

FYI, propylene glycol is a food grade product. No you shouldn't consume it, but it won't give you a painful death as your kidneys shut down either. If not worrying about something "that can kill you" isn't a concern, I don't what is!

 

O.K. let's try and straighten this out. 1st all I wanted to know is what were the reasons not to use automotive type i.e. bad for system metals, seals, etc (considering it protects all the metals in an automotive cooling system from corrosion). I am very aware of the toxicicity of ethylene glycol. 2nd He did use Hercules chryotec in the system it actually is not that cheap and was woundering how often to change it out. 3rd the amount of antfreeze he uses in the traps is only a few ounces each (50 50 mix to -34degrees) yes I know it doesn't have to be protected to -34. and that small diluted amount in a sewer system is less than gets spilled on the street when a car blows a hose. And before I get slapped with it, yes I know it would be more green to use rv antifreeze in the traps. Thanks for all the input.

 

1) Automotive antifreeze is more reactive with the metals (and combination of metals, and other materials) in a heating system than in an automobile system. It can lead to premature component failure.

2) You should test the antifreeze in the heating system, probably annually or as directed by the antifreeze manufacturer. They do lose effectiveness over time. The rate at which this occurs is system dependent. That's why you test. Just like your car....

3) You shouldn't put stuff into a septic or municipal sewer system that isn't supposed to be there. Green or not green, there are rules that we are supposed to follow. It generally helps if we do.

Good luck.

 

Car engines are a different animal. They require antifreezes with additives to protect the aluminum and other metals from corosion. Freezing is only a part of the reason they are used. Modern cars use different antifreezes than what would be used in an older car, and they shouldn't be mixed. Which would be "correct" for your boiler? I doubt anyone could you give you a correct answer. The other issue I mentioned is that the glycol can break down in time becoming acidic. Boilers like water that is on the other side of the PH scale, so you will need to do periodic water testing to see what's going on.

Antifreeze affects the heat carrying ability of the system. You have to go by what the boiler manufacturer advises.

RV glycol is only about five six bucks a gallon at the big box stores. Secondly, are you shutting the house down completely, NO heat at all? That could cause other problems in the home, and I'd be concerned about other damage besides freezing. That would be a good question for one of the other forums.

 

Perhaps you could contact the boiler's manfacturer and ask them? Every single boiler manufacturer that I'm aware of says the same thing. They don't say why, so perhaps it might be better for you to ask them that to ask us (even though the reasons given by the others were excellent).

 

I have seen propylene glycol fail in less than a year, and I've also seen it last 20 years. Extremely high temperatures will "burn" the antifreeze and cause it to become acidic and loose it's effectiveness. In a normal system, the antifreeze will last 3-5 years if not checked or maintained. There are test strips that are available for testing it's effectiveness. If it starts to get weak, there is an additive that you can put in that will restore it to it's origional performance. If it is let go for too long, there is no bringing it back, and it needs to be replaced. I know an engineer that, after being taught how to do it, tested his antifreeze before every heating season and treated as neccesary. He had a sample sent in to be tested by the manufacturer of the antifreeze, and they were shocked to hear that it had been installed 20 years prior after finding that it was in like new condition.
Also, if you think a little prestone in the septic system is ok, I will be glad to come over and paint your window trim with a little lead paint and insulate your pipes with a little asbestos. By the way, how far is the well from the septic tank? As far as I know, soil will filter out the bacteria and impurities in water, but chemicals will go right through. Makes me think of the old guy I saw at the hardware store buying some M copper tubing (may contain lead), and 50/50 solder so he could fix a leaky domestic water pipe. His response when warned about the ill effects of lead that is consumed was "I'm not going to live forever". I guess he didn't care if it affected the people who moved in after he was gone. RV antifreeze is cheaper than prestone, and much safer.