Mini-Splits
Ductless installs, inverter boards, sensors and error codes.
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.
Mini-Split Flare Connections That Don't Leak: Cutting, Flaring and Torque
The steps that keep mini-split flare joints leak-free, from cutting and deburring to flare size, oil, torque and nitrogen testing.
Mini-Split Line Set Length and Charge: When to Add Refrigerant
How factory pre-charge works on mini-splits, how to calculate additional charge for long line sets, and the limits on length and height.
How to Pull a Deep Vacuum: Micron Targets and the Decay Test
Evacuate a system properly, covering nitrogen pressure test, rig setup, micron targets, and how to read a standing decay test for leaks vs. moisture.
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.
How to Test a Mini-Split Thermistor (Temperature Sensor)
Test a mini-split room, coil, discharge or outdoor temperature sensor with an ohmmeter and the manufacturer's resistance table, and find out whether the sensor, wiring or board is bad.
Mini-Split Communication Errors: How to Troubleshoot Indoor-to-Outdoor Faults
A step-by-step approach to mini-split communication faults between the indoor and outdoor units, covering wiring, polarity, voltage and boards.
Working Safely on Mini-Split Inverter Boards
Why mini-split inverter boards stay dangerous after power-off, how to verify the DC bus is discharged, and how to approach IPM, voltage and compressor drive error codes.