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 P4 Error Code — Drain System Fault: Causes & Fix

  22 Apr, 2026

  What Mitsubishi P4 means, why the drain system faults, and how to fix P4 on Mitsubishi mini-split systems.

• Nor-Lake Refrigerator Error Code E1 — Causes & Fix

  22 Apr, 2026

  Troubleshoot Nor-Lake Refrigerator E1 on refrigeration equipment with checks for sensors, airflow, condenser condition, controls, and parts to price first.

• Rheem Classic Series Furnace Error Codes — Complete Guide

  22 Apr, 2026

  Rheem Classic and Classic Plus furnace error codes: all flash codes with meanings and repair steps for R801T, R96V, and Classic series models.

• Rheem Furnace Error Codes - All Flash Codes Explained

  22 Apr, 2026

  Rheem furnace flash codes: what each blink pattern means on Classic, Classic Plus, and Prestige series furnaces.