Successfully servicing refrigeration equipment requires understanding how the components of a system are designed to operate. While this is true of all components, it is especially true of electronic controls. Not understanding how some electronic controls operate and control a system can lead to misdiagnosing a system problem and costly repairs. It is best never to assume, but rather take the time to do some research and find out exactly how they operate. Guessing is rarely good and generally will lead to a misdiagnosis and cause a tech to replace the wrong part or component.
With today’s smart devices, finding information on a control becomes an easy task, and you should utilize that ability when required. For example, looking up an information sheet on a component can allow you to determine if the control is actually defective or performing as intended.
Recently, I was working on a walk-in freezer that was over defrosting due to a defective termination switch. The system had an electronic defrost timer and, after replacing the termination switch, I tested its defrost operation by manually placing the system into defrost mode. Since the termination switch was at room temperature when I installed it, I expected the defrost cycle to be very short or even terminate as soon as it was initiated. Instead, the system stayed in defrost until the defrost timer timed out and terminated the cycle based on time and not by temperature, as it should have. Since the termination switch was new, my first thought was the defrost time clock was defective. I had incorrectly diagnosed the problem. But before I changed out the timer, I decided to do a little research and find out more about how this electronic timer was designed to function. I was glad I did.
Using my smartphone, I found the timer’s product sheet and read about the timer. I discovered that if it “sees” a closed termination switch on the initiation of a defrost cycle, it will automatically terminate the defrost based on time and not temperature. It assumes the switch is stuck closed and prevents terminating a defrost cycle too quickly. Therefore, there was no issue with the timer.
The next day, I returned to the job site and initiated another manual defrost. This time, the cycle terminated by temperature as it should, and I was confident I had originally diagnosed the system correctly now that it was operating properly. If I had not researched the timer’s operation, I would have likely changed out a perfectly good timer, wasted the customer’s money, and questioned my original diagnosis.
So, the next time you come across a component that causes you to question its operation, or if you do not understand totally how it operates, do some research and better educate yourself on that component before replacing it or deciding it’s the cause of a system issue. Do not guess or assume but rather verify and confirm. By doing this, you will become a better technician and a more valuable asset to your customers and company.
Publication date: 3/6/2017