Heating
Gas furnaces, combustion and CO, heat pumps and defrost, boilers.
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 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.
Heat Pump Blowing Cold Air in Heat Mode: What's Normal and What's Not
Tell normal heat pump behavior (cool-feeling air, defrost) from real faults like reversing valve, O/B setup, low charge and aux heat problems.