Carrier Furnace Error Code 33
Limit circuit fault; indicates a limit, draft safeguard, flame rollout, or blocked vent shutoff switch is…
Limit circuit fault; indicates a limit, draft safeguard, flame rollout, or blocked vent shutoff switch is open; blower will run for 4 minutes or until open switch remakes, whichever is longer.
First step from the service manual
Check for dirty filter or restricted duct system, loose blower wheel, defective switch or connections, defective blower motor or capacitor, inadequate combustion air supply (flame rollout switch open), restricted vent, proper vent sizing, or excessive wind.
The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.
Get the full diagnostic procedure for 33.
- Step-by-step tests with expected resistance, voltage, and continuity values
- Wiring diagram references and connector pinouts from the OEM service manual
- Verified part numbers when replacement is required
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