Does home boiler Anti Freeze wear out ?

[treefrog25]

Hi ,

Five years ago, I put 4 gallons of Hercules: "Cryo-Tec AG" anti-freeze in my 15 gallon gas fired, hot water boiler system.
Last year I tested it with the test strips and added some "Corrosion Inhibitor".

I have noticed on the pressure relief drain tube some bright blue corrosion. Does this indicate that the anti-freeze is
no good and its time to flush out the system and put in fresh AF ?
Does it mean that the corrosion I see on the outside of the pipe is happening on the inside of all the copper pipes ?

Thanks,

Tim

 

[heaterman]

Hi ,

Five years ago, I put 4 gallons of Hercules: "Cryo-Tec AG" anti-freeze in my 15 gallon gas fired, hot water boiler system.
Last year I tested it with the test strips and added some "Corrosion Inhibitor".

I have noticed on the pressure relief drain tube some bright blue corrosion. Does this indicate that the anti-freeze is
no good and its time to flush out the system and put in fresh AF ?
Does it mean that the corrosion I see on the outside of the pipe is happening on the inside of all the copper pipes ?

Thanks,

Tim

Short answer...........yes. Your supplier should have test kits available with which you can determine what shape your antifreeze is in.
As a matter of similarity, think about how often the manufacturer of your car or truck recommends changing the antifreeze. Every 100,000 miles is the longest duration I know of.

BTW. the down tube on the pressure relief should terminate 6" above the floor so you can easily see if it is dripping or beginning to fail.

 

[in hot water]

excessive temperature, hard water, O2 ingress are a few of the things that can breakdown the inhibitor package. Temperature, not so much in hydronic systems, hard blend waters for sure, O2 is possible if you connect with non barrier pex for example.

Boost kits work fine, if it drops below 7 ph I would flush and start with new fluid as it takes a lot of boost chemical.

Not a bad idea to clean a system with hydronic cleaners before you add glycols. A dirty system can also stress glycols.

hr

 

[Gooserider]

Corrosion on the PRV drain tube is more suggestive that your PRV is dribbling a bit - you should not get any corrosion there as that tube should never see any moisture, let alone anti-freeze... However the earlier comments on the need for testing and upkeep on the stuff are spot on, especially if you are running through spaces were freezing is a real risk... (If you aren't, I'd question the need for anti-freeze in the first place)

Gooserider