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.

• Whirlpool Washer F1 Error Code — Control Board Fix

  6 Jun, 2026

  Diagnose Whirlpool Washer F1 Error Code - Control Board Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement.

• Whirlpool Washer F21 Error Code - Drain Fix

  6 Jun, 2026

  Whirlpool washer F21 means the machine took too long to drain. Clean the pump filter first; it fixes F21 in most cases and takes about 5 minutes.

• Whirlpool Washer F28 Error Code — Communication Error Fix

  6 Jun, 2026

  Whirlpool washer F28 means the main control board lost communication with the motor control unit. Reseat the wiring harness before replacing any boards.

• Burnham Boiler B26, Err 4, and Err 6 Codes

  27 May, 2026

  Burnham B26, Err 4, and Err 6 guide for safety-limit and flame-sensing faults on Alpine, Series 2, MPO, Pinnacle, ES2, and SCG boilers.