I continue to get the occasional question, worded something like, “..Hey, do them videos tell ya’ how to charge 410A systems?” And I go into an explanation about the DVD’s covering a review of refrigeration principles with R-22 and providing some discussion relative to 410A…or sometimes I just direct them here and suggest they may get their answer for the price of a websurf…
But, the question still takes me back a little, simply because I get the impression some people have never heard of any refrigerant other than R22, or never seen a refrigeration system containing any other refrigerant…I admit, I found out about the pressure thing with 410A indirectly from another tech, who had stumbled onto a R-410A system accidentally, with no knowledge of the refrigerant’s characteristics, and didn’t have a saturated pressure/temp chart for the alien chemical. All he knew was the suction pressure was near double what he was accustomed to seeing. He had the presence of mind to call someone who was familiar, and was quickly tutored as to what he was looking at.
But, if someone out there knows 410A exist, knows the saturated pressures are different, can get his hands on a P-T chart and is comfortable with the application of mechanical refrigeration principles, the question of how to deal with the system relative to it’s type of refrigerant, should be a no-brainer…or not even exist. It’s just another heat pump with another refrigerant…what’s not to understand?
Refrigerants are about pressures, if you want to talk about pressures. Someone, some time in history, designed a particular refrigerant for a particular reason, none of which I know. I just know there are more refrigerants to choose from these days than I can get in my truck at one time. I abandoned low and mid temp service work, just because of all the refrigerants. Use to, it was 12, 22 and 502. You could service about any system you went on with one of those 3 options. Then, with the initial demise of R-12 there were several retrofit drop-in’s available, with different folks choosing different strokes…and little convenience stores with 6 condensers, using maybe 4 different refrigerants, with some not identified…what a mess. But getting back to the point of the story, all the condensing units were still doing the same thing…cooling down the Budweiser and Miller 12 packs.
Refrigerants are about pressures, refrigeration is about temperatures. I’ve seen heat pumps running on R-12, R-22, R-500 and now, R-410A. And they all did essentially, the same thing…cool the house in the summer and warm it in the winter. And of course, they accomplish that by creating conditions conducive to heat transfer. Those conditions are indoor and outdoor coil temperatures. And the coil temperatures have been pretty much consistent since Day One of comfort cooling and heat pump applications.
We all tend to forget what we’re actually measuring when we hook up the gauges to a system. We grow dependent on pressure values and “beer-can-cold” suction lines, not thinking in terms of the saturated temperature of the pressure and it’s relationship with the temperature of the suction line. We’re just looking for 70 psi and a cold suction line. One positive aspect of servicing 410A equipment is the fact we’re all gonna’ have to go back to the basics for a while and actually think about saturated temperatures…at least until the 410A suction pressures become as familiar as the R22 have been, for so many years.