When checking an AC condenser with infrared, the coil image can tell you a lot about the condition and coolant charge. I know of no other way to detect coil restrictions.
Thermocouple, visual, non contact thermometer.
Most units have at least 6 sections, each fed by small (~1/8") tubes.
Photo caption says it is a 10 section coil? Is he counting stripes? I have never seen a 10 section coil in residential sized equipment that I can remember.
Their size makes them vulnerable to clogging.
There is almost always a filter or screen before a capillary type distributed tube and as Charlie pointed out, distributor tubes (not to be confused with capillary tubes on heat pumps) are substantially larger and not prone to blockage. If there is enough crap inside the refrigerant system to block a 1/8" tube, you have other serious problems.
If several become restricted, heat dissipation and efficiency are affected. A severe condition can result in liquid coolant re-entering the compressor,
This is hogwash in 99.9% of the cases. You can completely shut off the liquid line service valve and block all liquid refrigerant from leaving the condenser coil and it will not back up on the compressor unless the lines that run length exceeds the manufacturers design (in which case a receiver should have been installed in the circuit).
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.)
Anyone have any information on this? Maybe he’s talking about a section of coil not even being piped into the refrigeration circuit?
A 10 section coil condenser less than one year old.
This one has a normal IR signature.
Some AC technicians have told me, they charge systems according to coolant line temperatures, rather than pressure.
I would certainly hope that 100% rather than some of the technicians would be charging the equipment in this manner! The refrigeration gauges is not like the gas gauge in your car! But you must install them to make sure the thing doesn’t blow up in your face!
I often used a ΔT of the condenser coolant lines, along with heat rise, and a ΔT of the air across the evaporator coil
you all know what I think about this one!
to evaluate the operation of central air systems. I have also used this method on commercial chilled-water systems, and residential geothermal units.
Using this method in water systems is appropriate because you only have sensible heat in a liquid state.
(Of course, copper is not a great emitter. Electrical tape or adhesive paper stickers are necessary for more accurate readings.)
P.S. I am not a certified thermographer.
I am wondering if he is a certified HVAC Tech either?!
I don’t think this article is accurate and do not recommend anyone adapting this as a common practice.