Run capacitor
Common no-start and weak-compressor failure point. Match the microfarad and voltage rating.
Rheem Classic Series Error Codes — What It Means
Rheem’s Classic and Classic Plus furnaces (models R801T, R96V, R97V, R92P, and the RGFE/RGFJ series) are among the most common residential furnaces in North America. They use a blinking LED on the control board to communicate fault codes. Rheem also makes Ruud furnaces — identical hardware, identical codes. Open the lower access panel and count the LED blink sequence.
Flash Code Quick Reference
| Flashes | Meaning | Common Fix |
|---|---|---|
| 1 | Ignition lockout (retries exceeded) | Clean flame sensor; check gas |
| 2 | Low/single pressure switch open | Clean condensate trap |
| 3 | High pressure switch open (2-stage only) | Check hose and pressure switch |
| 4 | High limit device open | Replace filter; check blower |
| 5 | Roll-out switch open or flame without call | Safety issue — inspect HX |
| 6 | Inducer motor fault | Check motor RPM and wiring |
| 7 | Flame signal low | Clean flame sensor rod |
| 8 | Rollout switch circuit open | Manual reset; inspect burners |
| 9 | Reversed line voltage polarity | Rewire at disconnect |
| 57 | Abnormal operation / board fault | Check wiring; may need board |
Classic Series Model-Specific Notes
R801T (80% AFUE, single-stage): No condensate drain, so 2-flash codes always point to the inducer or pressure switch hose — never a blocked drain trap. These furnaces are simple and long-lived; most faults trace to a dirty flame sensor or weak blower capacitor.
R96V (96% AFUE, variable-speed): Has a variable-speed ECM blower motor. High-limit faults (4 flashes) on R96V often trace to low blower speed caused by high static pressure in the duct system rather than a dirty filter. Check duct static pressure if the filter is clean.
R97V (97% AFUE, 2-stage variable-speed): Two-stage gas valve means two pressure switches. A 3-flash code (high-pressure switch) can indicate the high-stage switch is stuck open. Verify both pressure switch hoses are intact — the second hose on a 2-stage inducer is easy to overlook.
Most Common Fixes
1 Flash: Ignition Lockout
- Look through the sight glass — did the igniter glow? If yes, suspect gas supply or flame sensor.
- If the igniter glowed but no flame appeared: verify gas valve opens (listen for click), check gas pressure.
- Remove the flame sensor and clean the rod with 400-grit sandpaper.
- Power cycle and retry.
2 Flashes: Pressure Switch Open (96/97% Models)
- Locate the condensate drain trap — white plastic U-trap at the furnace base.
- Disconnect the outlet hose and pour water through to verify free flow.
- Inspect the rubber hose from the inducer to the pressure switch for cracks.
- Test the pressure switch with a vacuum pump — it should close at approximately 0.6–0.8” WC.
4 Flashes: High Limit
- Replace the filter (Rheem 1” media filters clog in 30–45 days during heavy use).
- Verify all supply and return registers are open.
- On R96V, check blower speed — the motor should accelerate smoothly to full speed.
- If the limit still trips, have a technician check static pressure and heat exchanger condition.
7 Flashes: Low Flame Signal
- Remove the flame sensor (single 1/4” hex screw).
- Rub the metal rod with fine steel wool.
- Reinstall and power cycle.
Parts Often Needed
| Part | Notes |
|---|---|
| Flame sensor | Rheem 62-22868-92 |
| Hot-surface igniter | Rheem 62-23543-01 |
| Condensate trap | Rheem AP14230C |
| Pressure switch | 0.60” or 0.80” WC, model-specific |
| Blower run capacitor | 5–10 µF / 370V |
Technician Tips
Modern furnaces use LED flash codes on the control board to diagnose failures. Before calling for service, count the number of flashes between pauses and check your owner’s manual for the code chart. The most common furnace error — 1-4 flashes usually means ignition failure — is often caused by a dirty flame sensor. The flame sensor is a $15-30 part that takes 10 minutes to clean. Remove it with a 1/4” nut driver, gently scrub the metal rod with emery cloth or a dollar bill (yes, a dollar bill — it’s the right abrasiveness), and reinstall. This fixes about 60% of “no heat” service calls.
DIY vs Pro: Error codes related to pressure switches (usually 2-3 flashes) often indicate blocked vents or condensate drains — safe to check yourself. Codes related to gas valves or ignition modules (4+ flashes) are best left to a licensed HVAC technician.
Need Replacement Parts?
Before ordering, match the furnace part to the model number, electrical rating, and failure symptom. Check current prices on Amazon - prices and availability change frequently.
When to Call a Pro
Code 5 (rollout or flame without call) and code 9 (reversed polarity) require technician attention. Rollout on a Rheem Classic can indicate a cracked primary heat exchanger — CO can enter the living space through a cracked HX.
See Also
- Rheem Water Heater Error Codes — Complete Guide
- Rheem Furnace 5 Flashes Error Code — Flame Sensor Fault Fix
- Rheem Furnace 9 Flashes Error Code — Causes & Fix
- Rheem Air Handler E1 Error Code — Causes & Fix