What each Rheem code means — and what to do next. Stuck? AAA Comfort Air fixes Rheem systems across Central NJ, often same-day.
Rheem and Ruud furnaces and air conditioners are the systems we install most, so we know their quirks inside and out. When a Rheem unit acts up, the control board usually tells you why with a flash code.
Watch the red LED on the control board through the sight glass; it flashes a repeating pattern. Newer models show a 2-digit number on a display. The indicator is a red LED flash code (newer Prestige®/Endeavor™ models show a 2-digit number).
| Code | What it means | What to do |
|---|---|---|
| 1 flash | Locked out 1 hour after failed ignition | Flame sensor, igniter, or gas — call us |
| 2 flashes | Pressure switch open | Blocked vent/intake, inducer, or clogged condensate — call us |
| 3 flashes | Limit switch open (overheating) | Replace a dirty filter; if it repeats, call us |
| 5 flashes | Twinning / voltage / polarity fault | Wiring — call us |
| Code 22 | Main limit circuit open (overheating) | Restricted airflow — check filter & vents |
| Steady ON | Control board fault | Call us |
| LED off | No power to the board | Check the breaker and door switch |
⚠️ Codes can vary by model and control-board revision — always confirm against the label inside your unit’s access panel. For any gas, electrical, or refrigerant fault, call a licensed technician.
Watch the red LED on the control board through the sight glass; it flashes a repeating pattern. Newer models show a 2-digit number on a display.
You can try one power cycle at the breaker to clear a one-time fault. But if the same code returns, it’s a real fault — repeatedly resetting a gas or electrical issue can be unsafe. Call AAA Comfort Air at 609-665-3022.
AAA Comfort Air installs and repairs Rheem systems across Cream Ridge and Central New Jersey, with same-day and 24/7 emergency service. Call 609-665-3022.
Book online or call your local Rheem HVAC team — same-day & 24/7 emergency service.
