HVAC, Appliance, CNC, and VFD Error Code Repair Guides

Browse repair guides for HVAC, appliances, refrigeration, CNC alarms, VFD faults, generators, boilers, water heaters, and commercial equipment.

• Mitsubishi CNC Alarm 500 — Causes & Fix

  22 Apr, 2026

  What Mitsubishi CNC alarm 500 means on M70/M80 series, why servo error occurs, and how to fix it.

• Mitsubishi E5 Error Code - Drain Pump or Float Switch Fault

  22 Apr, 2026

  Mitsubishi mini-split E5 points to a condensate drain problem. Check the drain pan, lift pump, float switch, drain hose slope, and blocked tubing.

• Mitsubishi P8 Error Code — Causes & Fix

  22 Apr, 2026

  What Mitsubishi mini-split P8 means, why the compressor faults, and how to diagnose and fix it.

• Navien E006 Error Code — Causes & Fix

  22 Apr, 2026

  Diagnose Navien E006 Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement.