AC Not Cooling
Warm air, a low temperature split, or nothing running.
AC Breaker Keeps Tripping: How to Find Out Why
How to diagnose an air conditioner or heat pump that keeps tripping its breaker: a grounded compressor, a locked rotor, a shorted fan motor, wiring faults, high head pressure or a weak breaker.
AC Leaking Water Inside: Condensate Drain, Float Switch and Pan Problems
Why an air handler or furnace coil leaks water indoors, how to find the cause fast, and how to clear and protect the condensate drain so it doesn't come back.
AC Short Cycling: Why the Compressor Turns On and Off Too Often
How to diagnose an air conditioner or heat pump that short cycles, using how long it runs and what stops it: thermostat problems, safety switches, low charge, airflow, and oversizing.
Belt-Drive Blowers: Belt Tension, Pulley Alignment, Bearings and Setting Airflow
How to service a belt-drive blower on older furnaces, air handlers and rooftop units, including belt tension and alignment, bearings, adjustable pulleys and how they change airflow.
How to Clean an AC Condenser Coil the Right Way
How to clean a condenser coil without damaging it, which cleaners to use on copper-aluminum vs. all-aluminum coils, how to tell when it's dirty, and what a dirty coil does to pressures.
How to Clean a Mini-Split: Filters, Coil, Blower Wheel and Drain
How to deep clean a ductless mini-split indoor unit, including the coil, blower wheel and drain, plus the outdoor unit, with the right tools and without damaging the electronics.
How to Find a Refrigerant Leak: Methods, Common Spots and the Standing Pressure Test
A step-by-step leak search for AC and heat pump systems, the leak detection methods and where each works best, the most common leak spots, and how to confirm the repair.
How to Test a Blower Motor: PSC, Constant-Torque ECM and Variable-Speed ECM
How to tell which kind of blower motor you have and test it the right way, from capacitor and amp checks on PSC motors to control signals on constant-torque and variable-speed ECMs.
How to Test an HVAC Transformer: 24-Volt Checks, VA Rating and Shorts
How to test the 24-volt control transformer in a furnace or air handler, how to size a replacement by VA, and how to find the short that killed the last one.
Mini-Split Not Cooling or Heating: A Diagnostic Order for Ductless Systems
How to troubleshoot a ductless mini-split that runs but won't cool or heat: error codes, mode and remote settings, filters and blower wheels, the outdoor unit, sensors, communication and charge.
Replacing a Run Capacitor or Contactor: How to Pick the Right Part
How to choose a replacement run capacitor (µF, voltage, dual vs. single, size) and contactor (coil voltage, poles, amp rating), with the common mistakes that bring callbacks.
Servicing R-22 Systems in 2026: Recharging, Retrofits and Repair-or-Replace
What you can and can't do with an R-22 air conditioner or heat pump today, where R-22 comes from now, how retrofit refrigerants work, and how to help a customer decide between repair and replacement.
Thermostat Blank or No Power: Finding the Missing 24 Volts
How to troubleshoot a blank thermostat: batteries, the C wire, the furnace door switch, a blown board fuse, a tripped float switch, the transformer and power to the air handler.
AC Compressor Not Starting: Humming, Clicking or Nothing at All
Diagnose a compressor that won't start by what it does: humming points to capacitor or locked rotor, clicking to overload, silence to the control circuit.
AC Not Cooling? A Step-by-Step Diagnostic Checklist for Techs
Work an AC no-cool call in the right order, from the thermostat call to airflow, electrical and refrigerant charge, without guessing.
Condenser Fan Not Spinning: Capacitor, Motor or Control?
Find out why an outdoor condenser fan won't run, from the fan capacitor and seized bearings to the contactor, wiring and heat pump defrost.
Frozen Evaporator Coil: Causes, Safe Thawing and What to Check
Why AC evaporator coils freeze, how to thaw one safely, and the order to check airflow, charge and metering once it's thawed.
Furnace Control Board Fuse Blown (3A): Finding the 24V Short
Why a furnace control's low-voltage fuse blows and how to find the short in thermostat, outdoor unit or accessory wiring before replacing it.
How to Test an AC Contactor: Coil, Contacts and Voltage Drop
Test a condenser contactor the right way, from 24 V at the coil and coil resistance to pitted contacts and voltage drop under load.
How to Test a Run Capacitor: Meter Method and Under-Load Method
Test HVAC run capacitors two ways, with the meter's capacitance setting and under load with amps × 2652 ÷ volts, and know when to replace one.
Superheat vs. Subcooling: What Each Tells You and When to Charge by Which
What superheat and subcooling measure, how to take them, which one to charge by for TXV and fixed-orifice systems, and how to read them together.