Rheem gas_furnace Error Code E6

Limit Switch Open - Overtemperature

What does E6 mean?

Supply air temperature exceeded limit switch setpoint.

Common causes

Dirty filter
Blocked registers
Failed blower motor
Undersized ductwork

Diagnostic & testing steps

1. Replace dirty air filter
2. Verify all registers open
3. Check blower motor runs
4. Test blower capacitor
5. Measure temperature rise: 40-70°F normal range

Tools required

Multimeter
Thermometer

OEM parts & part numbers

High Limit Switch, Blower Motor, Blower Capacitor

Part numbers: 47-21854-01, 51-42001-05

Safety warning

⚠️ CO risk. Never bypass high limit switch.

Try DiagBuddy AI free — instant 30-second diagnostics for technicians.