One of the very first steps when it comes to diagnosing your home air conditioner, refrigerator, or even your vehicle’s air conditioner is understanding the temperature and the current pressure that your system is operating at. Having these facts along with the saturation point, the subcool, and the superheat numbers for the refrigerant you are working on are essential when it comes to really understanding what is going wrong with your system.
After a visual inspection the very next step for the most seasoned technicians is pulling out their gauges and checking the pressure and temperature. It just becomes second nature after enough calls. I have heard stories of rookie techs calling some of the pros on their team for help on a system that they’re stuck on. It doesn’t matter what the situation is. It doesn’t matter if you’re in Miami or in Fargo. It will never fail that one of the first questions the pros ask the rookie is what is your subcool and what is your superheat? Having and understanding these numbers is key to figuring out what to do next.
But, these numbers won’t do you any good if you don’t know what refrigerant you are dealing with and what the refrigerant’s boiling point is at each pressure level. This article aims at providing you with just that information.
R-123 Refrigerant Pressure Temperature Chart
R-123 refrigerant is most likely a rare find nowadays. It was originally introduced in the 1990’s as a replacement for the now phased out refrigerant known as R-11. You see R-11 contained chlorine. It was found that refrigerants that contain chlorine can actively damage the Ozone layer if they are released into the atmosphere. Once this was found out the world banded together and formed an international treaty known as the Montreal Protocol. This protocol banned CFC and HCFC refrigerants.
When R-11 was banned R-123 began to see more and more use in larger low pressure centrifugal chillers. It was hugely efficient and it had a much lower Ozone Depletion Potential then its predecessor. There were a lot of downsides to R-123 though. One of the biggest was that it was rated as a B1 on ASHRAE’s safety scale. That means that the refrigerant was toxic if breathed in or if you were exposed to it. This alone takes a lot of points away from its appeal but couple that with it being an HCFC refrigerant with an Ozone Depletion Potential as well then you have a perfect storm for another phase out.
R-123 was meant as a substitute or a standby when R-11 was phased out. It wasn’t meant as a permanent solution. That is why you now see more R-134a applications when it comes to centrifugal chillers. Not even R-134a is safe though folks as they are already trying to phase this out as well due to it’s high Global Warming Potential. The refrigerant market is always changing…
If you do in the off chance run into an R-123 system then you are going to need to know the pressures. Let’s take a look at our pressure chart below:
|Temp (F)||Temp (C)||Pressure (PSIG)||Pressure Liquid (PSIA)|