Bryant Furnace Error Code 34: Meaning and Fix
Applies to: Bryant furnaces with a two-digit status code LED (checked against the Bryant 310AAV manual).
Also shown as: 3 short 4 long, 3 short, 4 long flashes
Reading the furnace display
A furnace reports faults on a small status LED on the control board, seen through the sight glass in the blower door, or on a two-digit display. Watch a full cycle of the pattern and count the flashes, including the pause between groups, before you decide what you saw. The code chart is on the label inside the blower door.
This page lists the fault codes this brand documents, with likely causes and a short repair path. The codes apply to model numbers such as 310AAV; check the label on your unit to confirm yours.
What causes 34
- Flame sensor coated with oxide, grounded or poorly positioned
- Defective hot surface igniter
- Poor control ground or inadequate flame carryover or rough ignition
- Gas valve defective or turned off, or low inlet gas pressure
How to fix it
If you smell gas, leave the building and call your gas utility from outside; do not touch switches or the furnace. Switch the furnace power off before you open the blower door or touch the igniter or flame sensor, and call a licensed HVAC technician if you are not sure.
The code meaning comes from the manufacturer document listed under Sources. The causes and steps below are general troubleshooting guidance, not the manufacturer's service procedure.
- Make sure the gas shut-off valve is open. If you smell gas, leave the building and call your gas utility.
- Switch the furnace power off before touching the flame sensor.
- A coated flame sensor can be cleaned gently with fine steel wool, as the manufacturer's service label instructs. Leave the igniter alone.
- If the code returns, a technician should check flame sensor microamps, the igniter, the ground and the gas pressure.
- Restore power and run a heating cycle. If the code returns, call a licensed HVAC technician and give them the code, the board label and the furnace model number.
Questions
What does 34 mean on a Bryant furnace?
Code 34 (3 short, 4 long flashes) on a Bryant furnace means the control could not prove flame during ignition. The control tries three more times before locking out with code 14.
Can I reset the furnace myself?
The control can be reset by switching power off at the furnace switch or breaker for about 30 seconds, which clears some lockouts. If the same code returns, the fault is still present and the control will shut the furnace down again. Never bypass a safety switch to keep it running.
When should I call a technician?
Call a licensed HVAC technician for anything involving gas, the pressure switch, the limit or rollout switches, the igniter, the flame sensor or a control board replacement, or if the code keeps coming back after the simple checks.
Other brands with code 34
The same code can mean something different on another maker's appliance. Check the brand before you act.
Other Bryant furnace codes
Sources
Part numbers are OEM references; confirm fit by your model number before ordering. Meanings compiled from manufacturer and parts-retailer documentation; see sources below. Unplug the appliance before opening it.
Applies to models including 310AAV.