Carrier Furnace Error Code 34
Ignition proving failure; if flame is not sensed during the trial for ignition period, the control will…
Ignition proving failure; if flame is not sensed during the trial for ignition period, the control will repeat the ignition sequence 3 more times before lockout #14 occurs.
First step from the service manual
Check that flame sensor is not grounded, clean oxide buildup on flame sensor with fine steel wool, verify proper flame sense microamps (0.5 microamps DC min, 4.0-6.0 nominal), check gas valve, manual valve shut-off, defective hot surface igniter, control ground continuity, low inlet gas pressure, inadequate flame carryover, and green/yellow wire connection to furnace sheet metal.
The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.
Get the full diagnostic procedure for 34.
- 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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