There Really Is a Santa

A few weeks before Christmas in December 2005, I received a call from a technician in regard to a problem he was having with a walk-in freezer. The technician, "Doug," told me what he had done to the system before he made the call to ICOR. He said that when he looked at the sight glass he noticed that it was showing the system to be low on charge. Not having the proper refrigerant on his service van to do the job, he took off for the local supply house to pick up some refrigerant. Once he arrived, and after talking to the counter person, he walked out with a cylinder of One Shot® refrigerant. When he arrived back on the job, he pulled his gauges out of his van, along with the cylinder of One Shot, and started adding gas to the system. He said that when the sight glass cleared he assumed that it had the right amount of charge. After the system had run for awhile, the owner said that the system wasn't getting as cold as it used to, and that's when Doug turned to ICOR for help.

Once we started talking about the problem he was having with the system, I realized that I was talking to an A/C repair guy who had never worked on a refrigeration system before, which he confirmed. With that in mind, I started asking him questions regarding system pressures. He said that the low side was around 18 lbs. and the high side was around 120 lbs. He stated that the ambient temperature was 40oF and that he noticed that the fan cycling control had the condenser fan running as well. After a few more questions, I determined that the fan cycle control was set for an R-12 system, so I thought to myself, is this system R-12 or R-502? Once he determined that it was an R-502 system, by looking at the TXV and seeing that it had a purple tag on it, Doug told me that he was going to return to the supply house and pick up a new fan cycle control, which he thought would solve the problem.

About a week later Doug called to tell me he could not get the walk-in below 4oF and that the owner needed it to be 0oF or below. I asked him if he had ever calculated superheat or subcooling, and he replied "No." With that said, he pulled out his P/T chart for R-502. That's when I told him that he needed to use the P/T chart for One Shot instead. Then I made the connection-he had not removed the R-502 charge before he added in the One Shot and had mixed the two refrigerants. I explained to him the different reasons you should not mix refrigerants. He told me that he had added One Shot to the system on two separate occasions. I'm thinking that by now the system should have more One Shot in it than R-502, making the One Shot P/T chart more accurate. After checking, we determined that the subcooling was running right at 10oF. He thanked me for helping him, and we wished each other a Merry Christmas.

Just when I thought I had heard the last from Doug and his walk-in, he called me the Friday before Christmas to tell me that the walk-in was back up to 40oF and low on charge. Then he told me that he had found the leak, made the repairs and put the system back to a full charge. After discussing the difference between compressor and evaporator superheat, adjustments were made to the TXV until he had a superheat reading of 30oF at the compressor. Doug said the box temperature was falling and that it was getting so cold that his shoes were sticking to the floor.

When a technician calls ICOR with questions or problems, he gets to talk to, not Santa Claus, but someone who has been in the trenches and understands how frustrated you can get when things go wrong. The moral to this story is simple, when you purchase ICOR refrigerants you get way more than just gas!

Jamey Hale
Technical Support Supervisor
ICOR International, Inc.