When checking an AC condenser with infrared, the coil image can tell you a lot about the condition and coolant charge. We know of no other way to detect coil restrictions. Most units have at least 6 sections, each fed by small (~1/8") tubes. Their size makes them vulnerable to clogging. If several become restricted, heat dissipation and efficiency are affected.

A severe condition can result in liquid coolant re-entering the compressor, resulting in excessive wear and premature failure. This was reported with one of the units shown. (Note: Due to variations of condenser capacity, some manufacturers may not use every coil section, and one restricted section may not constitute a problem.)

Picture to follow here. 

Some AC technicians have told us, they charge systems according to coolant line temperatures, rather than pressure. We often used a ΔT of the condenser coolant lines, along with heat rise, and a ΔT of the air across the evaporator coil to evaluate the operation of central air systems. We have also used this method on commercial chilled-water systems, and residential geothermal units. (Of course, copper is not a great emitter. Electrical tape or adhesive paper stickers are necessary for more accurate readings.

If significant coolant leaks are suspected,the power to the condenser can be shut down to stop the circulation fan.The condenser is then observed with the thermal imaging camera while the system is still under pressure and the leak can be detected. 

Please contact us if you have a project where you feel your air conditioning equipement is not performing as it should.