Rheem Furnace Error Code 57: Meaning, Causes, and Fixes

The Rheem Furnace Error Code 57 commonly appears on Rheem and Ruud gas furnaces to indicate a pressure switch or venting problem that prevents safe ignition. This article explains what Code 57 means, common causes, step-by-step troubleshooting, safety checks, and when to call a licensed HVAC technician. The guidance aims to help homeowners identify likely issues and take safe, effective next steps.

Code	Primary Meaning	Immediate Action
57	Pressure Switch Fault / Blocked Venting	Check vents, furnace power, and condensate/pressure tubing; call technician if unresolved

What Rheem Furnace Code 57 Means

Rheem Furnace Error Code 57 typically signals that the furnace’s pressure switch did not close or did not detect proper pressure during the ignition sequence. This safety device verifies that the inducer motor and venting system are moving combustion gases correctly before allowing main gas flow.

Key Point: A closed pressure switch is required for safe burner ignition; Code 57 prevents the furnace from firing when the switch indicates unsafe venting or airflow.

How The Pressure Switch Works

The pressure switch monitors the negative pressure generated by the inducer motor. When the inducer runs, a vacuum forms in the venting/pressure tubing and the switch closes, signaling the control board that combustion airflow is correct. If the switch remains open, the control board registers a fault such as Code 57 and locks out ignition.

Common Causes Of Code 57

• Blocked Intake/Exhaust Vents: Debris, bird nests, snow, or nearby landscaping can restrict airflow.
• Inducer Motor Failure: If the inducer won’t start or is weak, the pressure switch won’t close.
• Dirty Or Faulty Pressure Switch: The switch diaphragm can fail or tubing can be clogged or disconnected.
• Disconnected/Blocked Pressure Tubing: Cracked or kinked tubing or condensate clog in the vent can prevent proper vacuum.
• Control Board Or Wiring Issues: Loose connections or failed relays can produce the same symptom.
• Condensate Trap Or Drain Blockage: On high-efficiency furnaces, clogged condensate lines can affect pressure sensing or safety switches.

Safety First: Before Troubleshooting

Always prioritize safety. Turn off power to the furnace at the service switch or breaker before inspecting internal components. If natural gas smell is present, evacuate the area and call the gas company or emergency services.

Do Not attempt gas valve, burner, or flame sensor replacements without HVAC experience. Incorrect handling can cause carbon monoxide risk or fire.

Step-By-Step Troubleshooting For Rheem Furnace Code 57

1. Check Error History And Lights

Observe the control board LED or digital display to confirm Code 57 and note if other codes are present. Some models indicate repeated lockouts or multiple faults that change the diagnosis.

2. Inspect Intake And Exhaust Vents

Check the furnace exterior vent termination for blockages like nests, ice, snow, leaves, or other obstructions. Clear visible debris and ensure at least the manufacturer’s recommended clearance from walls, shrubs, and other openings.

3. Verify Inducer Motor Operation

Restore power and run the furnace through a call for heat while listening for the inducer motor start. A healthy inducer should spin up and produce a consistent sound. If it does not run or is noisy, the inducer assembly or capacitor may need service.

4. Inspect Pressure Tubing And Connections

With power off, trace the small rubber or silicone tubing between the vent collar, pressure switch, and inducer. Look for kinks, cracks, blockages, or disconnected ends. Replace brittle tubing and reattach securely. Tip: Blow gently through tubing to verify it is clear.

5. Test Pressure Switch Function

A multimeter can determine if the pressure switch closes when the inducer runs. With the furnace energized and inducer operating, measure continuity across the switch terminals. Important: Only trained homeowners comfortable with electrical testing should perform this. If the switch does not close, replace the switch or correct upstream problems causing low vacuum.

6. Check Condensate Lines And Trap (High-Efficiency Units)

High-efficiency condensing furnaces have condensate traps and drains that can clog and affect safety switches. Inspect and clean traps and ensure proper slope in drain piping. Clear blockages using appropriate methods to avoid damaging components.

7. Evaluate Wiring And Control Board

Examine wiring to the pressure switch and inducer for loose connectors, corrosion, or broken wires. A damaged control board relay could falsely report pressure faults; if wiring is intact but Code 57 persists, board diagnostics by a technician are advised.

When To Call A Professional HVAC Technician

If basic checks (vents, visible tubing, condensate) do not clear Code 57, or if the inducer motor, pressure switch, or control board needs replacement, contact a licensed HVAC technician. Replacing gas or combustion-related components requires proper tools, safety testing, and knowledge of combustion/venting codes.

Call A Technician If: The inducer motor fails to run, pressure switch tests bad, wiring is damaged, the control board indicates multiple faults, or any repair requires gas valve, burner, or heat exchanger work.

Parts That Often Need Replacement

• Pressure Switch
• Inducer Motor Or Motor Assembly
• Rubber/Silicone Pressure Tubing
• Condensate Trap Or Drain Components
• Control Board (in rare cases)

Preventive Maintenance To Avoid Code 57

• Keep intake and exhaust vent terminations clear of debris, snow, and vegetation.
• Schedule annual furnace inspections before heating season; include inducer and pressure switch checks.
• Replace air filters regularly to reduce strain on combustion and venting systems.
• Inspect and replace aging pressure tubing during service visits.
• Clear condensate lines and traps periodically on high-efficiency units.

Estimated Repair Costs And Time

Repair costs vary. Replacing a pressure switch typically ranges from $100–$250 including labor and parts. Inducer motor replacement often costs $300–$700 depending on model and labor. Control board replacement can be $400–$900. Exact costs depend on location, furnace model, and whether additional issues exist.

Most pressure-switch or tubing fixes can take 30–90 minutes. Inducer motor jobs generally take 1–3 hours. If the heat exchanger or gas valve requires work, expect longer service time and higher cost.

FAQ: Quick Answers For Rheem Furnace Code 57

Can a dirty air filter cause Code 57?

A clogged air filter can indirectly affect furnace performance but usually does not directly trigger Code 57. Replace filters to maintain overall system health.

Is Code 57 dangerous?

Code 57 is a safety lockout designed to prevent unsafe combustion when venting or pressure is compromised. It is not immediately dangerous but indicates a condition that should be corrected before operation continues.

Will resetting the furnace fix Code 57?

Power cycling or resetting can temporarily clear a code but will not resolve the underlying issue. If the problem persists, the code will return and professional diagnosis is recommended.

Does Code 57 apply to all Rheem furnaces?

Code numbering can vary slightly by model and control board. Code 57 most commonly relates to pressure switch/vent issues on many Rheem/Ruud gas furnaces, but owners should check the specific unit’s service manual for exact definitions.

How To Document Information For A Technician

When scheduling service, provide the furnace model and serial number, exact error code and LED blink pattern, recent changes (new landscaping, cold snaps, power outages), and any troubleshooting already performed. This information speeds diagnosis and helps the technician bring correct parts.

Useful Resources And Manuals

Owners should reference the furnace’s installation and service manual for detailed error code charts and wiring diagrams. Rheem and Ruud online technical libraries provide model-specific documentation, parts lists, and troubleshooting flowcharts.

Tip: Photograph the control board label and vent terminations to share with the technician for remote guidance.

Summary Checklist For Homeowners Facing Code 57

• Check vents and clear visible obstructions.
• Inspect pressure tubing for cracks, kinks, or disconnection.
• Verify inducer motor runs during call for heat.
• Check and clear condensate trap/drain on condensing units.
• Reset power only after safety checks; do not repeatedly reset without addressing root cause.
• Call a licensed HVAC technician for inducer, pressure switch, or control board replacement.

If additional help is needed, homeowners may contact Rheem customer support or a local licensed HVAC contractor to schedule inspection and repair. Maintaining proper venting and following preventive maintenance significantly reduces the risk of recurring Code 57 faults.