Wheeler on HVACR: Coil cleaners or destroyers?
I was asked recently to come look at a job as a third-party observer. A large medical-equipment manufacturer was having problems with its HVACR maintenance. The scope of the job was pretty big, involving some 800+ tons of rooftop equipment scattered over three buildings. They have had the equipment maintained on a quarterly basis by a local discount service company over the past 10 years since the systems were installed. The problem it seems is that, despite the regular maintenance, the company had already been forced to replace 10% of the rooftops. It had had several drain-pan failures, and motors were failing so rapidly that the manufacturer had a maintenance man working full-time to replace them.
The reputable contractor I was with was happy to hear me give my opinion. First of all, the condenser coils had been regularly cleaned using a corrosive, foaming coil cleaner, which had destroyed the coil tube-fin bond, as well as large patches of fins. The cleaning solution was also responsible for the drain-pan failures and was causing the cabinets to rust prematurely. The rising head pressures caused by the coil destruction was wasting massive amounts of energy. I estimate the total efficiency loss at about 30%. In addition, the rising head pressure situation - the result of the condenser-coil deterioration - would soon cause compressors to fail.
But that's not all. It looks like the fans were being oiled with a spray-type silicone lubricant that is primarily designed to loosen rusted-on bolts. In other words, it is primarily a solvent that tends to wipe the lubricant out of the motor bearings. The manufacturing company would have been better off without "preventive maintenance." It had actually done more harm than good.
After I left with the contractor, he mentioned he doubted they would bid on the job since the equipment was in such bad shape. He rather pompously stated that if the manufacturer didn't care if their equipment was any better maintained than that, he certainly didn't want the work.
Venturing dangerously into the position of biting the hand that was feeding me, I asked, "What type of coil cleaner and oil does your company use?" Again, with the same righteous indignation, he described the foaming coil cleaner they use as having totally safe ingredients, mentioning laurel sulfate and other baby-shampoo ingredients. The lubricants? Standard motor oil (the best choice).
I asked, "Are you sure? Do you actually have written specifications telling your people what to use?"
He replied, "Well, no, we don't actually have anything written, but we do a much better job than the other contracting company, and we would never use the wrong things."
When we got back to the shop I asked to see a bottle of the coil cleaner he uses. He brought me some, so I read the warning label out loud. Now, on the front of the label are the words: Safe for coils! Contains no acids! On the warning label, however, it read: Caution, corrosives! Contains sodium hydroxide and surfactants.
Sodium hydroxide? That's the chemical name for lye, not an acid but an extremely dangerous alkali. When you spray this stuff on aluminum coil fins, you have the same two chemicals together that you find in a popular crystal drain cleaner: lye and grains of aluminum. The aluminum is in there to make the solution hot to clean the drain quicker and to minimize damage to the pipes. You see, in the presence of water and lye, the aluminum foams and dissolves. No wonder the coil cleaner foams when it hits aluminum fins! Safe? No way! Not for people or for coils.
Well, my self-righteous contractor friend explained that the cleaner only damages fins if it is left on, and that they carefully wash the coils thoroughly so there is no damage. And I said, "Show me!"
Well, first he took me to a site where they were maintaining the equipment, and the coils looked great. However, after checking the serial numbers I noted that the units were less than a year old and the coils had never been cleaned yet. So I asked to see something they had been maintaining for a longer time.
Reluctantly he took me to a medical clinic where they had a full-coverage contract for more than 10 years. Apparently he had never been up on that roof; the coils and the equipment were in terrible shape. There were some large, old commercial units that were about 15 years old. Most of the cover screws were missing and the coil fins were noticeably deteriorated.
There also were two light-commercial rooftop systems that were less than five years old. Here the thinner aluminum fins were totally destroyed. Lightly brushing my finger across the coil, the brittle, oxidized fin material fell off in heaps leaving only a thin layer of aluminum around the copper coil interior.
Point made? Yes, but he still thinks his company does a better job. The whole situation puts me in mind of the old joke: "You know it's going to be a bad day when you see the '60 Minutes' crew waiting at your company's front door."
So, why am I telling you this story? You likely sell the same coil cleaner at a nice profit. Am I asking you to quit selling it? No, too many contractors still want to buy it. I just want you to know.