Proper testing of system anti-freeze will help prevent problems down the road
By George Lanthier
In many of my seminars, especially those about hydronics and cold-weather servicing of heating systems, an issue comes up that always surprises me that people don’t know about: how non-toxic or inhibited propylene glycol solutions, or system anti-freeze, can go bad and you may end up with a freezing acid. So it’s time to drop in at B&B Mechanical and see what’s up.
Bubba comes in one Monday morning and finds his Uncle Bruce pouring over some literature on new homes.
“Hey, what’s up Unk, looking to buy a new house?” questions Bubba.
“Not really, Bubba,” replies Bruce, “I’m thinking of retiring soon and just want to see what’s available.”
“Retire, really?” asks Bubba. “You really going to throw in the towel on the business?”
“Well, I am going to be 66 this spring and it’s not getting any easier. You know the turnover we’ve had in young guys and it’s like their attitude is the biggest problem. I don’t mind putting money into a fella to learn, it’s just that they don’t want to, or at least the ones we’ve lucked out with don’t. Or maybe luck had nothing to do with it. I was hoping you would take over the business and then it would be your problem,” giggles Bruce.
“Well, as it turns out, I wanted to talk to you about that and isn’t it funny how things work out?” quips Bubba. “See Unk, I’ve got a chance to get on the local fire department and I’m really thinking about it, after all I’ll be 34 this spring and don’t have much put away for the future. Medical keeps going up and, well, I don’t have to tell you. You’ve been great to work for and I’ve learned a lot. On top of that, the owner of Friendly Oil says if I go on the department he will let me work part-time. He won’t take me away from you, but …”
“You’ve been a great nephew and an even better apprentice, Bubba; in fact you’re a master in your own right now. Remember how you put up with those losers Puffy and Bobo? What a pair they were!” giggles Bruce again.
“I know what you mean, Boss,” replies Bubba. “That Puffy guy, geez was he bad or what?”
“Well, enough of the old times for now,” states Bruce. “How’d it go last night and over the weekend?”
“Only big deal was that big house over on Broken Branch Road,” states Bubba. “The house is now five years old and the anti-freeze has gone bad and needs to be replaced. They said we can do it as quick as we want, but I did put the fear of God into the guy.”
“You did the right thing Bubba, as usual,” remarks Bruce. “If it’s gone bad it does have to go.”
Do you know what Bubba and Bruce are talking about? Did you know that you must not only check the anti-freeze freeze point, but also the pH of the fluid in the system?
Just about everybody at this point knows you must check the freeze point and the best tool to do this with is a refractometer (See Figure 1). We talk about this in our book The Hot Water Handbook and here’s what we say:
“Whenever anti-freeze is used around domestic hot water systems it should be of a non-toxic variety. Generally, its use around domestic systems is primarily for use with any system where protection from freezing and or the bursting of pipes is desired. “Protection against toxic mixing must be avoided and the use of an inhibited propylene glycol solution is always desired and preferred. This is an extremely important point to remember since even the best products eventually outlive their life expectancy, and if there is a failure of the heat exchanger every precaution must have been taken to protect the end-users from toxicity.
“Never use automotive or ethylene glycol solutions or mixes. These solutions have been known to cause severe personal injury, property damage and death.
“The mixture of anti-freeze should always be adequate to provide the desired degree of freeze protection. Hard and fast rules such as ‘50%-50% mixtures’ don’t always provide the amount of protection required. Anti-freeze also generally provides for two levels of protection, ‘anti-freeze’ and ‘anti-burst’.
“‘Anti-freeze’ is the point at which the solution becomes slushy and may not move through the system, but the system is still protected at that temperature.
“‘Anti-burst’ is the point at which the solution freezes and will not move through the system, and just at the point where pipes containing the solution will finally burst.
“A few other important things to remember when you are using anti-freeze:
“Make sure that the heater, exchanger or tank in use is compatible with anti-freeze solutions. Piping materials, copper, plastic, steel, etc., should also be checked for compatibility with the solution to be used.
“Always check the pH value of the concentration after installation or during periodic maintenance. If the pH is different than seven and is not neutral, drain and flush the system and replace the anti-freeze.
“Finally, when testing anti-freeze, a high-quality tester should be used. The authors have seen the effect both in financial damage and legal entanglements caused by the use of the wrong tester or test strips.
“The only right way to evaluate the condition and effectiveness of any anti-freeze is through the use of a refractometer. A refractometer is the only device that follows the ASTM Standard D3321 in providing results that are precise to +/-1.0F. Through the use of such a device you are able to accurately determine the true quality of the anti-freeze in use regardless of it’s type.”
In Figure 2 is the scale of the refractometer shown in Figure 1. The refractometer is available from us at our Web site www.FiredragonEnt.com in our Tool Box. It will test propylene glycol solutions and battery acid by simply adding a small sample to the “measuring window” and closing the cover and then exposing the sample to light so an accurate determination may be made. The sample captured within the device is merely held to the light and then viewed through the eyepiece.
But, did you get the part about the pH? We also talk about the pH of the water or system fluid in our book Hydronic Systems. Here’s a chart I borrowed from myself from that book (See Figure 3).
The basic problem is that as the piping, fittings, boiler and everything else in the system ages, they will actually start to turn the propylene glycol and water solutions to acid. So it’s important that you not only check the freeze levels of the solution, but also the pH. In my experience the best tool to do that with today is the electronic pH pen tester and you can also find those most anywhere for under $50 (See Figure 4).
Well, that’s it for me now and I guess we will have to check in with Bruce and Bubba and see what happens down the road.
George Lanthier is the owner of Firedragon Enterprises, a teaching, publishing and consulting firm. He can be reached at 132 Lowell Street, Arlington, MA, 02474-2756. His phone is (781) 646-2584, fax at (781) 641-7099 and his e-mail is FiredragonEnt@comcast.net.