Rheem Furnace Error Code 22: Diagnosis and Repair Guide

The Rheem furnace error code 22 signals an ignition or flame sequence issue that requires careful diagnosis to restore safe, reliable heating. This guide explains what Rheem Furnace Code 22 means, common causes, step-by-step troubleshooting, recommended repairs, parts to check, and when to call a professional. The goal is to help homeowners and technicians quickly identify root causes and implement safe, effective fixes.

Item	Key Point
Code Meaning	Ignition or flame failure during startup sequence
Common Causes	Dirty ignitor, faulty flame sensor, gas valve issue, pressure switch problem, airflow restrictions
Initial Checks	Reset furnace, inspect error history, ensure power and gas supply
DIY Fixes	Clean flame sensor, replace ignitor, clear vents, check condensate line
When To Call Pro	Gas valve replacement, sealed combustion diagnostics, repeated failures

What Rheem Furnace Error Code 22 Means

Rheem Furnace Code 22 typically indicates the control board did not detect a flame during the expected time window after the ignition sequence started. This is often reported as “no flame detected” or “ignition lockout.” The furnace attempts ignition, opens the gas valve, energizes the ignitor or spark, and expects a flame sensor signal; when that signal is absent the board logs Code 22.

How The Ignition Sequence Works

Understanding the ignition sequence clarifies why Code 22 occurs. The sequence starts with the thermostat call for heat, inducer motor startup, pressure switch verification, ignition source activation (hot surface ignitor or spark), gas valve opening, flame appearance, and flame sensor confirmation. A failure at any point produces an ignition fault like Code 22.

Common Causes Of Code 22

Ignitor Or Ignition Component Failure

A cracked or weak hot surface ignitor or defective spark module prevents reliable ignition. Ignitor deterioration is a frequent cause, especially in older units or systems with frequent cycling.

Dirty Or Faulty Flame Sensor

The flame sensor must detect the presence of combustion. A coated or misaligned flame sensor can fail to register flame and trigger Code 22 even if the burner lights momentarily.

Gas Supply Or Gas Valve Problems

Insufficient gas pressure, a closed gas shutoff, or a failing gas valve prevents sustained combustion. Gas valve solenoids or internal valve failures are less common but critical causes of ignition failure.

Pressure Switch Or Inducer Issues

The pressure switch confirms correct venting and inducer operation. A stuck or leaking pressure switch or blocked venting can stop the ignition sequence before the gas valve opens.

Airflow, Venting Or Draft Problems

Blocked return grills, clogged filters, closed registers, or obstructed flue/venting can change combustion dynamics and lead to ignition failure or flame rollout, producing Code 22.

Initial Safety Checks Before Troubleshooting

Always prioritize safety. Turn off power and gas when doing hands-on work. Check the following before deep diagnostics: ensure the thermostat is set properly, confirm furnace power switch is on, verify the gas valve is open, inspect the condensate drain and vents for major blockages, and reset the furnace to see if the code clears temporarily.

Step-By-Step Troubleshooting For Rheem Furnace Code 22

Step 1: Record The Fault History

Document how often Code 22 occurs and any accompanying behavior such as clicking, repeated restarts, or lockouts. Intermittent faults suggest component degradation while constant faults imply a failed part or supply issue.

Step 2: Reset And Observe A Full Ignition Cycle

Reset the furnace and watch the ignition cycle. Note whether the inducer starts, whether the ignitor glows or sparks, whether the gas valve opens (you may hear a click), and whether the flame sensor registers. This observation narrows down the stage where failure occurs.

Step 3: Inspect And Clean The Flame Sensor

Remove the flame sensor and gently clean it with fine-grit sandpaper or emery cloth until the metal is shiny. Reinstall and test. Cleaning the flame sensor often resolves Code 22 when the sensor is merely coated with combustion residue.

Step 4: Test Or Replace The Ignitor

Inspect the ignitor for hairline cracks or discoloration. Hot surface ignitors are fragile; a visible crack requires replacement. Use a multimeter to check resistance for typical values in the furnace manual. Replace the ignitor if readings are out of spec or if it visibly fails.

Step 5: Check Gas Supply And Valve Operation

Confirm the household gas supply is active by testing another appliance or checking the gas meter. Listen for the gas valve click and use a combustible gas leak detector to ensure no leaks. If the valve energizes but gas flow is absent, a professional gas valve diagnosis is required.

Step 6: Verify The Pressure Switch And Inducer

Inspect the inducer for smooth operation and obstructions. Check the pressure switch tubing for cracks or disconnections. Use a multimeter to confirm the pressure switch closes when the inducer runs. Replace or repair tubing and switches as needed.

Step 7: Evaluate Airflow And Venting

Replace filters, clear return and supply vents, and inspect vent terminations for bird nests or debris. For high-efficiency sealed-combustion units, confirm the intake and exhaust pipes are unobstructed and properly sloped.

Step 8: Examine Control Board And Wiring

Look for loose, corroded, or damaged wiring at the control board, flame sensor, ignitor, and gas valve. Faulty connectors can interrupt the flame-detection circuit and cause Code 22. Replace damaged wiring and secure connectors.

Parts, Tools, And Materials Often Needed

• Replacement Flame Sensor Compatible With Rheem Model
• Hot Surface Ignitor (OEM Recommended)
• Multimeter For Resistance And Continuity Tests
• Fine-Grit Sandpaper Or Emery Cloth For Sensor Cleaning
• Screwdrivers, Nut Drivers, And Safety Gloves
• Combustible Gas Leak Detector
• Replacement Pressure Switch Or Tubing (If Required)

When To Replace Parts Versus Repair

If a flame sensor is simply dirty, cleaning is appropriate and cost-effective. A cracked ignitor should be replaced immediately. If wiring or connectors show corrosion, replacement is recommended. Gas valve or control board failures usually require replacement and professional service due to gas-safety implications.

When To Call A Licensed HVAC Technician

Contact a professional when the diagnosis points to gas valve replacement, persistent pressure switch faults, control board replacement, or sealed-combustion diagnostics. Also call a technician if the user is not comfortable working with gas or live electrical components. A licensed technician ensures proper repair, testing, and safety compliance.

Preventive Maintenance To Avoid Code 22

Regular maintenance reduces the risk of Code 22. Recommended tasks include annual HVAC tune-ups, cleaning the flame sensor during service visits, replacing filters every 3 months, inspecting venting and condensate drains, and maintaining proper airflow throughout the home.

Cost Estimates And Timeframes

Costs vary by region and model. Typical ranges: flame sensor replacement $75–$200, ignitor replacement $100–$400, pressure switch replacement $100–$350, control board replacement $300–$800. Simple sensor cleaning or filter changes take under an hour; component replacements may take 1–3 hours depending on complexity.

Safety Tips And Best Practices

• Turn Off Power And Gas Before Inspecting Internal Components.
• Use Manufacturer-Approved Parts To Maintain Warranty And Safety.
• Document Error Codes And Repair Steps For Technician Reference.
• Ensure Proper Ventilation And Carbon Monoxide Detectors Are Installed.

Model-Specific Notes And Resources

Rheem furnaces share common components but may vary by model and year. Refer to the furnace’s nameplate and owner’s manual for exact part numbers and diagnostic LED patterns. Rheem technical bulletins and the furnace’s error code legend provide model-specific guidance. OEM parts and wiring diagrams help ensure correct replacements.

Keywords And SEO Relevance

This article targets searches for “Rheem Furnace Code 22,” “Rheem error code 22,” and related queries by explaining code meaning, causes, DIY fixes, parts, and when to call a pro. Including these phrases in headings and body improves visibility for users seeking prompt troubleshooting for Rheem furnaces.

Additional Troubleshooting Resources

• Rheem Owners Manual And Error Code Chart (Model-Specific)
• HVAC Forums And Technician Guides For Similar Ignition Faults
• Manufacturer Technical Support Hotline
• Licensed HVAC Service Providers For On-Site Diagnostics

Key Takeaways For Rheem Furnace Code 22

Rheem Furnace Code 22 signals a flame-detection or ignition failure. Most common DIY fixes include cleaning the flame sensor, replacing a failing ignitor, checking airflow and vents, and ensuring gas supply. Professional service is advised for gas valve, control board, or sealed-combustion issues. Following a regular maintenance schedule reduces recurrence and ensures safe furnace operation.