Bryant 355MAV Error Code 14: Ignition Lockout

What Does Code 14 Mean?

Status code 14 on the Bryant 355MAV indicates an ignition lockout — the furnace attempted to light the burners 4 times and failed each time. The control board locks out the gas valve and will automatically reset after 3 hours.

The most common cause is a dirty flame sensor. The flame sensor is a thin metal rod positioned in the burner flame path. Its job is to detect whether the gas actually ignited by measuring a small electrical current through the flame. Over time, oxide buildup accumulates on the sensor rod, reducing the current below the minimum threshold (0.5 microamps DC), causing the control to think ignition failed even when flames are present.

If you notice the inducer motor running at full speed during the lockout, the manual specifically notes that this means flame sense was lost 3 times within 60 minutes of cumulative gas valve operating time. This pattern typically points to flame rollout rather than a simple dirty sensor — refer to status code 34 for that scenario. Other possible causes include a defective hot surface igniter that isn't getting hot enough to light the gas, or a gas supply issue.

Common Causes

How to Fix It: Clean the Flame Sensor

What You'll Need

• Fine-grit emery cloth or Scotch-Brite pad
• 1/4-inch nut driver or hex-head screw
• Flashlight
• Clean dry cloth

Steps

1. Turn off power at the breaker or power switch and shut off the gas supply valve Locate your electrical panel and turn the furnace breaker to OFF. Find the gas shutoff valve on the gas line leading to the furnace and turn it to the closed (perpendicular to the pipe) position. If you smell gas, leave immediately and call your gas company.
2. Locate the flame sensor Remove the burner access panel. The flame sensor is a thin metal rod (usually bent at a 90-degree angle) mounted near the burner assembly, typically on the opposite end from the igniter. It is held in place by a single 1/4-inch hex screw and has one wire connected to it.
3. Remove the flame sensor Disconnect the wire from the flame sensor terminal. Remove the mounting screw and carefully pull the sensor out. Note its orientation so you can reinstall it the same way.
4. Clean the sensor rod with fine emery cloth Gently rub the metal rod portion of the flame sensor with fine-grit emery cloth to remove the gray or white oxide buildup. Work the entire length of the rod that sits in the flame path. Do not use sandpaper or anything coarser than fine emery cloth. Some HVAC professionals recommend using a Scotch-Brite pad instead to avoid residue. Wipe the rod clean with a dry cloth when finished.
5. Reinstall the flame sensor Insert the sensor back into its mounting hole in the same orientation as before. Tighten the mounting screw securely but do not overtighten. Reconnect the wire to the terminal — it should snap or push on firmly.
6. Restore power and gas Replace the burner access panel. Turn the gas supply valve back to open (parallel to the pipe). Turn the breaker back ON. You can wait for the 3-hour auto-reset, or reset immediately by cycling the furnace power switch OFF for 30 seconds, then ON.

When to Call a Professional

Contact a licensed HVAC technician if:

• Cleaning the flame sensor does not resolve the lockout
• The igniter does not glow at all during the ignition sequence
• You smell gas but the burners do not ignite
• The inducer motor runs at full speed during lockout (possible flame rollout issue)
• The furnace ignites but flame cuts out repeatedly within seconds
• Code 14 keeps returning after successful cleaning