Bryant Furnace Code 13 Troubleshooting and Fixes

The Bryant furnace Code 13 indicates a specific fault in the unit’s control and ignition sequence. This article explains the meaning, common causes, diagnostic steps, and safe repairs to restore reliable heating. It is aimed at homeowners and technicians seeking accurate, actionable guidance while emphasizing safety and when to call a professional.

Code	Primary Meaning	Common Causes	Suggested Action
Code 13	Pressure Switch Or Venting Problem	Blocked vent, failed pressure switch, inducer motor fault, loose tubing	Inspect venting, check switch continuity, test inducer, replace faulty parts

What Does Bryant Furnace Code 13 Mean?

Bryant furnaces use a diagnostic LED and code display to communicate operational faults. Code 13 generally signals a pressure-switch-related issue or a problem with the inducer/venting system. The control board expects a pressure switch closure during the draft/inducer stage and reports Code 13 when that signal is missing or inconsistent.

How The Pressure Switch And Inducer Work

The inducer motor creates negative pressure to safely clear combustion gases out the vent before ignition. The pressure switch senses that negative pressure and tells the control board it is safe to continue. If the board does not receive the closed pressure-switch signal at the correct time, the furnace will lock out with Code 13 to prevent unsafe operation.

Typical Causes Of Code 13

• Blocked Or Restricted Venting: Debris, bird nests, snow, or collapsed vent pipes can prevent proper draft.
• Faulty Pressure Switch: The switch can fail electrically or become mechanically stuck.
• Inducer Motor Problems: Broken motor, capacitor failure, or seized bearings reduce draft.
• Cracked Or Disconnected Tubing: The rubber/vinyl hose linking the inducer housing and pressure switch may be split or loose.
• Control Board Or Wiring Issues: Damaged wires, poor connectors, or a failing control board can prevent the switch signal from being read.

Safety First: Before Any Inspection

Always shut off power to the furnace at the breaker and wait for moving parts to stop before opening the access panels. If gas work or combustion testing is required, call a licensed HVAC technician or gas professional. Improper repairs to venting or gas components can cause carbon monoxide hazards.

Tools And Materials Needed For Basic Diagnostics

For homeowners comfortable with basic checks, useful tools include a multimeter, screwdriver set, replacement tubing, vacuum with brush, and a camera or phone for inspecting vent terminations. Technicians will use manometers, amp meters, and pressure gauges for more precise testing.

Step-By-Step Diagnostic Checklist

1. Observe The Furnace Behavior

Document when Code 13 occurs — at initial call for heat, intermittently, or after power cycling. Note any unusual noises from the inducer motor or delayed inducer startup.

2. Inspect The Outdoor Vent Termination

Examine the vent cap for debris, nests, ice buildup, or signs of animals. Clear any obstruction and ensure the vent termination is securely attached and oriented properly per the installation manual.

3. Check The Exhaust And Intake Piping

Follow the PVC or metal vent runs for sags, separations, or crushed sections. Ensure proper slope and support. A partially blocked or collapsed pipe reduces inducer performance and can trigger Code 13.

4. Inspect Pressure Tubing And Connections

Locate the small rubber or vinyl tube between the inducer housing and the pressure switch. Check for cracks, loose clamps, or water accumulation. Replace any damaged tubing and reseat connections firmly.

5. Test The Pressure Switch With A Multimeter

With power on and inducer running during a call for heat, measure continuity across the pressure switch terminals. The switch should close (show continuity) when the inducer creates negative pressure. If it does not, the switch may be defective or the inducer is not producing sufficient draft.

6. Verify Inducer Motor Operation

Listen for the inducer at startup; it should spool up smoothly without grinding. If the inducer fails to start or runs weakly, check power to the motor and measure current draw. Replace or service the inducer motor if electrical or mechanical faults are present.

7. Inspect Control Board And Wiring

Check the control board for burned traces, loose connectors, or corrosion. Trace the wiring from the pressure switch to the board for pinched or frayed sections. Repair or replace wiring harnesses as needed.

When The Pressure Switch Itself Is The Problem

If the inducer creates adequate vacuum but the pressure switch does not close, the switch is likely faulty. Pressure switches are relatively inexpensive and often straightforward to replace. Ensure the replacement matches the original switch’s specifications, including the cut-in pressure and terminal type.

Common Inducer Motor Issues And Fixes

Inducer motors can fail due to age, dirt buildup, or electrical faults. Symptoms include loud noises, vibration, failure to reach rated RPM, or no start. Cleaning the blower wheel and housing, lubricating bearings if serviceable, or replacing the inducer motor assembly are typical fixes.

Venting Design And Installation Errors

Incorrect vent sizing, long horizontal runs without proper fall, or shared venting with other appliances can reduce draft and cause persistent Code 13 faults. Verify the system matches Bryant’s installation specifications and consult a professional when changes are required.

Temporary Steps To Restore Heat Safely

• Clear visible vent blockages and ensure vent terminations are open.
• Replace small pressure tubing if cracked or clogged with water.
• Reset the furnace and observe whether the unit completes the start sequence.

These are temporary measures. If Code 13 persists, discontinue attempts and schedule a professional service call.

When To Call A Professional HVAC Technician

Professional service is recommended when diagnostic checks point to internal gas, electrical, or combustion issues, or when the homeowner is uncomfortable performing tests. A qualified technician will have tools to measure inducer vacuum, evaluate combustion, and confirm safe operation post-repair.

Typical Repair Costs And Parts

Costs vary by region and whether the homeowner or a technician performs the work. Typical parts and ballpark costs (parts only) include pressure switch ($30–$120), inducer motor ($150–$450), vent components ($30–$200), and control board ($200–$600). Labor costs depend on the complexity of the repair.

Preventive Maintenance To Avoid Code 13

• Schedule annual furnace tune-ups with combustion and vent checks.
• Keep outdoor vent terminations clear of debris and ice.
• Inspect pressure tubing and inducer for wear at each service interval.
• Change air filters regularly to maintain overall system performance.

Related Codes And What They Mean

Bryant furnaces use different codes for distinct faults. Codes related to pressure and inducer issues may appear similar; refer to the furnace’s service manual for exact definitions. Code 12 may indicate rollout or flame issues, while Code 13 focuses on pressure/draft detection. Understanding the specific sequence and LED patterns helps pinpoint root causes more quickly.

Resources And Where To Find Replacement Parts

OEM Bryant parts are available through authorized dealers and many HVAC supply houses. For model-specific parts and service manuals, consult Bryant’s official resources or trusted suppliers. When ordering parts, verify the furnace model number and serial number to ensure compatibility.

Practical Troubleshooting Case Examples

Example 1: A homeowner found Code 13 after a heavy snowstorm. Clearing packed snow from the vent termination and replacing a split pressure tube cleared the error and restored normal operation. Example 2: A furnace repeatedly showed Code 13 with no visible vent obstruction. A technician found a failing inducer motor that lacked sufficient RPM; replacing the inducer resolved the fault.

Key Takeaways

Code 13 Signals Pressure Or Inducer/Venting Problems. Start with vent and tubing inspection, then test pressure-switch continuity and inducer function. Address obvious obstructions but engage a licensed technician for electrical, combustion, or gas-related repairs.

Following recommended preventive maintenance reduces the chance of Code 13 reoccurrence and extends furnace lifespan.