Troubleshooting With Schematic Diagrams


A Note From Jim…


If you’re not in the HVACR service business at the moment, you probably don’t know that by far, the majority of work a service technician does has to do with troubleshooting electrical problems and replacing failed components such as transformers, relays, capacitors, printed circuit boards, etc…

Or, if you’ve been in the HVACR service business for any length of time, you already know that about 80% of what we do is related to solving electrical problems, and not connecting a set of gauges to a refrigeration system and “adding some gas” because the complaint is that the system isn’t cooling enough (I could rant about that issue, but then this ‘note’ would turn into a book, so I’ll get back to my original point).

In either case, there are 6 simple points you want to understand relative to electrical troubleshooting, and then replacing the right component in a residential or light commercial HVAC system:


1. If you’re not able to read and interpret schematic diagrams, you’re engaging in a lot of guesswork, and you’ll wind up replacing parts that aren’t the source of the problem. Bad for you…bad for the customer….bad for the HVACR service industry.


2. Learning to read and interpret schematic diagrams is just like learning a foreign language. I call it “Schematicspeak” (don’t try to look that up in the dictionary because I made it up), and you just have to knuckle down and do it.


3. Once you really learn the fundamentals of troubleshooting with schematic diagrams, you can apply that knowledge to whatever type of equipment you are servicing at the moment. And, yes, if you want to learn how to troubleshoot electronic circuits, the first thing you need to know is how to troubleshoot fundamental electrical circuits, because electronics ain’t nothin’ but electricity on steroids, so quit freaking about about “solid state” or “electronic control” system troubleshooting, and make sure you know….really know….the fundamentals of using wiring diagrams to troubleshoot electrical problems.


4. Once you nail down the idea of using schematic diagrams to troubleshoot and come up with a correct diagnosis, you are on your way to establishing that fundamental foundation of troubleshooting that I’m always harping on….the idea that in order to find out what’s wrong with something, you need to know what right is in the first place. And, to be sure, knowing what “right” is, is often just common sense and a having a general understanding of what resistance reading you should get if a part is OK rather than failed, or where you should read a given voltage or not read it at a certain point in a circuit, but another part of knowing what “right” is in the first place is being able to obtain (and understand, for cryin’ out loud) the information that a manufacturer provides about their specific equipment and their specific troubleshooting procedures that apply to solving a specific problem.


5. No school or training program alone can take you all the way through what I described in point #4. To get that accomplished takes getting the fundamentals from someone, somewhere, somehow who can get you fully understand what you need to know about the fundamentals, And then,  after you get that done, it takes field experience, and obtaining and understanding and interpreting the information you need from the equipment manufacturer in order to be able to effectively troubleshoot, replace a component, and consistently get paid for what you do.


6. At Technical Training Associates, our job is to help you accomplish the first part of your job (becoming effective at troubleshooting HVACR electrical systems) so you can then effectively pursue the second part of your job (understanding manufacturer’s specific diagrams and procedures), so you can troubleshoot and repair equipment, and get paid for doing it.

We have a DVD training package you can buy so you can learn the fundamentals of schematics and using them to troubleshoot. The price $280.00, and you can get details on it by clicking on the link below. 

It’s called  The HVACR Electrical Troubleshooting With Schematic Diagrams Training Package.



Technical Training Associates
PO Box 2259
Green Valley, AZ 85622-2259
Phone: 520-625-6847

Click to watch a segment from one of our HVAC Technician Training Video Programs for free!