This article was written by Senior Refrigeration tech Jeremy Smith. Big thanks to Jeremy for his contributions to HVAC School and the tech community.

Having spent many years in the trade and many years reading posts from techs on forums and social media, a big issue that I see is that troubleshooting is something of a lost art.

Troubleshooting is where the rubber meets the road for a service technician. Nobody cares what certifications you have, what union you belong to, or anything else. If you can't find the problem and solve it in a timely fashion, your customer and employer are not going to be happy.

One of the things that I think most guys struggle with is the mental aspect of troubleshooting. I'll relate this in the form of a recent call I was sent on to “clean up.” It was a no-heat call in a small convenience store. Trane RTU on a zone sensor.

The tech called me and related that the unit had a call for heat at the unit, but the ignition sequence didn’t start. We talked a little about the problem, and he checked some limits and a few other things. He wound up ordering an ignition board and limit sensors. These were replaced late that night, and the unit still didn't work.

I was sent the next morning. Now, we get into the mental part of troubleshooting.

I met the tech so that he could communicate the basics of what he did. We talked for about 10 minutes before he went on to his job, and I went to have a chat with the trouble unit.

Twenty minutes later, I had the problem solved. I found a failed RTRM board. Now, you guys that do Trane all the time probably aren't surprised, but let's analyze what went wrong and how this could have been handled on a “one-stop” basis.

What did I do that the first tech didn't?

For starters, I took everything that I was told about the unit: what it was and wasn't doing and what everybody and their brother thought was wrong with it, and I threw it all out. I put it in a box in my head, closed the lid, and locked it.

I dug out the basic Trane “Service Facts” book, started the troubleshooting procedure from Step 1, and followed it to the end.

Now, I can make these arrogant claims about how I'm a Billy Badass service guy and how I'm more awesome than anyone else, but the simple fact is that I'm not. I do things a little differently and think a little differently than many others, and that sets me apart.

What did the first tech do wrong? While I'm not in his head, I think that he focused on why the heat didn't work instead of taking the unit AS A WHOLE and diagnosing it as a whole—kind of like the guy who can't figure out why the fridge is warm and spends an hour working on it only to find the plug pulled.

So, the mental aspect of troubleshooting cannot be ignored.

Start at the beginning, work the process and troubleshoot the entire system. Being willing to read the manufacturer's troubleshooting info isn't a newbie move; it shows maturity.

Work on the troubleshooting mindset. Don't be a parts changer.

—Jeremy

(Edited by Bryan Orr, any mistakes are my fault)