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.
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Buderus Boiler Fault Code A1 - Sensor or Service Alert
Buderus A1 can mean a boiler sensor circuit fault or service reminder. Check the NTC sensor, connectors, condensate siphon, and sub-code.
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Burnham Alpine Boiler Error Codes - Ignition, Sensor, Limit, and Vent Faults
Burnham Alpine boiler faults cover ignition lockout, flame loss, temperature sensors, limit trips, vent pressure, condensate, and control errors.
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Burnham Boiler E2 Error Code - Pressure Switch Fault
Burnham boiler E2 means the pressure switch failed to close or opened during operation. Check vent blockage, condensate backup, hoses, inducer, and switch.
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Comfortmaker Furnace E4 Error Code - Ignition Failure Lockout
Comfortmaker E4 means ignition failure lockout. Watch the igniter, clean the flame sensor, verify gas-valve voltage, and check gas pressure safely.