Short Cycling
Runs a few seconds or minutes, then shuts off.
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.
How to Check Furnace Gas Pressure: Inlet and Manifold with a Manometer
Step by step for measuring furnace inlet and manifold gas pressure with a manometer, typical ranges for natural gas and propane, how to adjust, and how to clock the meter.
Furnace Temperature Rise: How to Measure It and What the Reading Means
How to measure furnace temperature rise correctly, where the normal range comes from, how to estimate airflow from it, and what a high or low rise tells you.
Furnace Flame Sensor: Microamp Readings, Cleaning and When to Replace
How flame rectification works, how to measure flame sensor microamps, what readings are normal, and how to fix weak flame signal.
Furnace High Limit Switch Tripping: Causes and How to Fix It
Why a furnace's high limit opens, how to confirm it with temperature rise and static pressure, and when the switch itself is the problem.
Furnace Pressure Switch Troubleshooting: Open, Stuck Closed and Dropping Out
Diagnose furnace pressure switch codes by measuring the inducer's draft with a manometer and checking vent, intake, hose, condensate trap and switch.
Furnace Short Cycling: 7 Causes and How to Pin Down Which One
Diagnose a gas furnace that lights and shuts off too soon, from flame sensing and limit trips to oversizing and thermostat settings.
Oversized AC: The Symptoms, Why It Happens and What to Do
How to recognize an oversized air conditioner, why it hurts humidity control and equipment life, and the options short of replacing it.