Some of today's coil cleaners may do more harm than good in the maintenance of HVACR equipment.
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.