Carrier HVAC Error Code 34: How to Fix Ignition Proving Fault

Q: What does Carrier error code 34 mean?

Error code 34 means the furnace control board did not detect a flame after the gas valve opened. This is typically due to a dirty flame sensor, bad igniter, or gas supply problem.

Q: How do I reset Carrier error code 34?

Turn off power to the furnace for 30 seconds, then turn it back on. If the error persists, troubleshoot the flame sensor or call a professional.

Q: Can a dirty flame sensor cause error 34?

Yes, a dirty flame sensor is the most common cause. Cleaning the sensor with fine-grit sandpaper often resolves the error.

Q: What is a flame sensor?

A flame sensor is a safety device that detects the presence of a flame. If it doesn't sense a flame, it shuts off the gas valve to prevent unburned gas from accumulating.

Q: Is it safe to clean the flame sensor myself?

Yes, it's safe if you turn off power and gas before starting. Always follow safety precautions and consult your owner's manual.

Abstract

Carrier HVAC error code 34 indicates an ignition proving fault, usually meaning the flame sensor didn't detect a flame after the gas valve opened. This is often caused by a dirty flame sensor, but could also be a bad igniter or gas supply issue.