HomeGuidesWhat a Real AC Diagnostic Includes: Our Owner Walks Through the Process
What a Real AC Diagnostic Includes: Our Owner Walks Through the Process
Last updated: November 1, 2026 · Reviewed by Colton Air Conditioning, NV license 0092120
Reviewed by Colton Air Conditioning, NV license 0092120 A diagnosis is the moment a homeowner decides whether to trust the person in the driveway. When the reason given for a broken AC does not match what gets fixed, people stop believing the next explanation too. This interview asks Colton's owner what a diagnostic visit should actually measure and show, with a focus on the two-story homes common around Southern Highlands. Related reading: AC running but not cooling.
The interview
Q1. Which measurements do you take before you name a cause?
When I diagnose an air conditioning system, I'm trying to identify the actual cause of the problem, not just the symptom. Depending on the complaint and equipment, that can include checking electrical components, operating voltages, amperage, capacitors, contactors, refrigerant pressures, superheat, subcooling, airflow, temperature differences, safety controls, and system operation. I also look at the relationship between those readings.
Q2. How do you show a homeowner what you found? Photos, readings, the old part?
For homeowners in Southern Highlands, my advice is to hire someone who can explain why a component failed or why the system isn't operating correctly, not just tell you what they want to replace. At Colton Air Conditioning, I believe a proper diagnosis should give you answers, not create more questions.
Q3. What is a common misdiagnosis you have seen on systems someone else looked at first?
A real air conditioning diagnostic involves considerably more than connecting gauges and telling someone their refrigerant is low. Unfortunately, that's exactly what some homeowners experience. For example, low suction pressure doesn't automatically mean a system needs refrigerant. It could indicate restricted airflow, a dirty evaporator coil, an improperly configured blower, or a refrigerant metering problem. Adding refrigerant without understanding the underlying issue can actually make the situation worse. I've seen systems that were repeatedly charged with refrigerant when the real problem was something entirely different.
Local context
Airflow is part of the diagnosis
ENERGY STAR notes that airflow problems can reduce a system's efficiency by up to 15 percent, so a diagnostic that skips the blower and ductwork can miss the real cause.
Leaky ducts can look like a failing AC
ENERGY STAR says about 20 to 30 percent of the air moving through a typical home's ducts is lost to leaks, holes and poor connections.
Who may handle refrigerant
Under the Clean Air Act, technicians who service equipment that could release refrigerant must hold EPA Section 608 certification. More for nearby homeowners: Southern Highlands and AC diagnostic and repair service.
FAQ
What should an AC diagnostic include? Readings on the electrical parts, refrigerant side and airflow, and a clear explanation of the cause. Colton's owner says: “Depending on the complaint and equipment, that can include checking electrical components, operating voltages, amperage, capacitors, contactors, refrigerant pressures, superheat, subcooling, airflow, temperature differences, safety controls, and system operation.” Can duct leaks cause poor cooling? Yes. ENERGY STAR estimates 20 to 30 percent of duct airflow is lost in a typical home. Does a technician need certification to work with refrigerant? Yes. EPA requires Section 608 certification for technicians who service refrigerant equipment.
Schedule
Book online or call (702) 738-6976 to schedule.