#Diagnosis

Tech Tips:

Underlying Problems That Get Missed
Today, I ran a service call with another tech where the previous tech had diagnosed an intermittent piston restriction. I read the history beforehand. For the past several years, there were many assorted comfort complaints and a lot of minor charge adjustments in both the summer and winter. It is worth noting here that the […]
Read more
How I Failed to Re-diagnose: The Lesson I Learned
This is the tale of how I found myself stuck on a service call for over 12 hours on a weekend due to my failure to re-diagnose an issue. I was working for a service company that had many accounts with local gas stations. These were large customers, and we did everything we could to […]
Read more
Wide, Narrow, Wide Diagnosis
When you walk up to a piece of equipment, you want to follow a process to ensure that you accomplish five things: #1 – You diagnose the fault correctly. #2 – If possible, you find the “why” of the failure. #3 – Find any other problems or potential problems with the system that can cause […]
Read more
The HVAC/R Diagnosis Pyramid of Skill
WARNING: THIS ARTICLE CONTAINS GENERALIZATIONS. IT DOES NOT APPLY TO EVERYONE, AND WE HAVE ALL PROBABLY BEEN ALL OF THESE AT ONE POINT OR ANOTHER. IF YOU FEEL PERSONALLY ATTACKED, I SUGGEST FINDING A SAFE SPACE AT A WEST COAST UNIVERSITY AND BORROWING A BINKY FROM A NEARBY TODDLER. ALSO, MY CAPS LOCK BUTTON IS […]
Read more
Famous Last Words (Before a Callback)
By:Bryan Orr  You've probably heard the famous last words, “Dude, watch this,” before a concussion, burn, shock, broken bones, or some other bodily harm. This phrase has become synonymous with young guys doing something dumb to impress their friends. Technicians have two common phrases that may not lead to bodily harm (although sometimes they might), […]
Read more
Use Your Senses First
A good technician uses their senses before they use diagnostic tools. Is your suction line abnormally cold? Make sure the evaporator coil isn't frozen, and inspect for obvious airflow issues like a dirty filter or evaporator coil. Is your liquid line abnormally warm to the touch? It could be a dirty condenser, condensing fan issue, […]
Read more
Troubleshooting For HVAC/R – Gathering Data 
This article is part 3 in a 5-part series by Senior Refrigeration and HVAC Technician Jeremy Smith. Let's start with step#1 in the flowchart: Gather data. This is why we spend money on those fancy digital manifolds, shiny electrical meters, and other gadgets, widgets, and doodads. It isn't to brag about them on Facebook; it's […]
Read more
Troubleshooting For HVAC/R – The Don’t List
This article is the second in a 5-part series by Senior Refrigeration and HVAC tech Jeremy Smith.  The Ground rules I've spent some time thinking about troubleshooting and the processes and procedures that I use to find problems. Not the “why isn't my air-conditioner running?” problems, but the “Things just aren't quite right”-type problems—the really […]
Read more
The Troubleshooting Mindset
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 […]
Read more

Podcasts:

Diagnosis, Reconfirmation, Parts Changers, and YOU
By:Bryan Orr This episode of HVAC School is a Kalos meeting where Bryan talks to his team about an incident where a leak was erroneously detected on the evaporator coil. The system was three months old, and one of our junior techs diagnosed a leak on the evaporator coil. (What?? That never happens!) So, the […]
Read more
The 5 Readings Every Tech Must Know Well
By:Bryan Orr In this episode of HVAC School, Bryan covers the “5 pillars of refrigerant circuit diagnosis” and why they matter. They are: Superheat Subcool Suction pressure Head pressure Air temp split (delta T)   These 5 readings give you a holistic idea of the A/C system. Instead of getting hooked on checking only superheat […]
Read more
Full System Diagnosis – There is More to Check
By:Bryan Orr In this episode, Bryan goes back over the basics and stresses the importance of diagnosing the whole system. I'll cut to the chase: inspection is NOT overrated. Inspections help you become more familiar with HVAC systems and can help you catch on to minor issues before they spiral out of control. Check air […]
Read more
loading

To continue you need to agree to our terms.

The HVAC School site, podcast and tech tips
made possible by generous support from