Bryant and Carrier: One Platform
Bryant is a Carrier sibling brand. They share the same furnace platforms, control boards, and error code systems. The same code on a furnace from either brand means the same thing. A Carrier Tech Tip covers both brands together. A Bryant technician can use Carrier service documentation and vice versa.
This guide applies to Bryant 355A, 340A, 315A, 310A, and legacy models. It also covers the Carrier equivalents that share these platforms: the 59SC, 58MXB, 58CVA, and others. If you see a code on a Bryant furnace, look in this guide. If you see the same code on a Carrier furnace, look in this guide. The answer is the same.
Two Diagnostic Systems
Bryant furnaces use two display methods. Older models and basic current models use a blinking LED on the control board. The number of blinks equals the error code. Count the blinks. That is your starting point.
Evolution and Concierge models with 2-digit displays show numeric error codes directly. These models also log the last 10 fault codes in memory. You can scroll through the history on the thermostat.
Some Bryant models use a 4-pin diagnostic connector on the control board. A service tool or the Evolution thermostat reads these pins. The tool displays the error in clear text. No blink counting needed.
LED Flash Codes
1 flash: Ignition failure. The furnace tried to ignite 3 times and failed. The board locks out. Check gas supply, igniter, and flame sensor. A dirty flame sensor causes this code on many Bryant furnaces. Clean the sensor with fine steel wool.
2 flashes: Pressure switch stuck closed. The switch showed continuity before the inducer motor started. Replace the pressure switch. Do not bypass it.
3 flashes: Pressure switch stuck open. The switch did not close during the inducer pre-purge period. Check the vent pipe for blockages. Check the condensate drain for clogs. A frozen vent termination can cause this code in cold weather.
4 flashes: Open limit circuit. The high temperature limit or roll-out switch tripped. This equals Code 33 on models with 2-digit displays. Check the air filter first.
5 flashes: False flame signal. The board detected flame without the gas valve energized. This is safety-critical. The gas valve may be leaking. Call a professional immediately.
6 flashes: Ground fault or polarity problem. Neutral and hot wires are reversed. The ground connection may be loose. Check the furnace electrical connections. A reversed polarity at the outlet can cause intermittent lockouts.
7 flashes: Gas valve relay stuck open or closed. Replace the main control board. The relay is soldered to the board and not serviceable separately.
8 flashes: Blower motor fault. The blower did not reach the required speed. Check the motor, capacitor, and wiring. A failing capacitor is common on older Bryant furnaces.
2-Digit Numeric Codes
Code 13: Limit circuit lockout. The limit switch tripped 3 consecutive times. This is the most common Bryant error. A dirty air filter causes 80 percent of Code 13 faults. Replace the filter first. If the code returns, check for closed supply registers, a blocked return, or an oversized furnace.
Code 33: Single limit circuit trip. The limit opened once but the furnace recovered. This is an advisory, not a lockout. The furnace cleared the fault on its own. Investigate the root cause before it escalates to Code 13.
Code 31: Pressure switch open. The switch did not close when the inducer started. Check the vent pipe and condensate drain. This code matches the 3 flash LED pattern.
Code 34: Ignition lockout. The furnace failed to detect flame after 3 attempts. Match this with 1 flash on LED models. Check gas pressure first.
Code 45: False flame. Flame detected with no call for heat. This matches 5 flashes. The gas valve may have failed closed or the flame sensor may be shorted. Do not reset and walk away.
Code 22: Abnormal flame or power loss. The flame signal dropped below the minimum threshold during operation. Check the flame sensor rod and wire. A corroded sensor produces a weak signal.
Evolution System
Evolution and Concierge models use a thermostat with a full-color touchscreen display. Error messages appear as text on the screen. You do not need to count blinks. The thermostat tells you the fault by name and suggests troubleshooting steps.
The Evolution system also records a fault history log. You can access it from the installer menu. The log shows the last 10 errors with date and time stamps. This helps identify intermittent problems that only happen at specific times or under specific conditions.
Common Failure Pattern
The most common Bryant fault is Code 13 and 4 flashes. The sequence goes: the limit switch trips once (Code 33 advisory), resets, trips again, resets, trips a third time, and the board locks out with Code 13. The homeowner often notices nothing until the third trip.
The filter is dirty. Replace it and cycle power to reset. In 8 out of 10 cases, this fixes the problem. If the code returns, open all supply registers and check for closed dampers in the ductwork.
When to Call a Professional
A Code 13 that returns after replacing the filter and opening all registers points to a blower motor problem or a cracked heat exchanger. Stop resetting and call a technician.
Code 45 (false flame) requires immediate gas valve testing. Do not reset the furnace without testing. A leaking gas valve can fill the heat exchanger with gas. The next ignition cycle can cause a fire or explosion.
Do not reset a Bryant furnace multiple times without fixing the root cause. Repeated resetting can damage the igniter and the control board. If the furnace locks out again within one heat cycle after a basic fix, bring in a licensed HVAC technician. They can perform a combustion analysis and measure temperature rise across the heat exchanger.
Most Bryant furnace errors point to simple fixes: a dirty filter, a blocked vent, or a corroded flame sensor. Start with the basics. Replace the filter. Check the condensate drain. Clean the flame sensor. If those steps do not work, call a professional.