York Error Code R4: High Limit Switch Open
Warning: Your York furnace has shut down due to a high limit error. This prevents overheating, but you'll need to troubleshoot to restore heat.
How to Fix York Code R4
- Step 1: Replace the air filter. A dirty air filter is the most common cause of overheating. Use the filter size noted on the furnace.
- Step 2: Ensure all return air vents are open and unobstructed. Do not block them with furniture or rugs.
- Step 3: Wait 30 minutes, then try resetting the furnace by turning it off and then on again at the breaker. If the error reappears, call a qualified HVAC technician.
How to Reset York Code R4
- Turn off the furnace power switch, usually located on or near the unit.
- Turn off the circuit breaker for the furnace. Wait 30 seconds.
- Restore power at the breaker and flip the furnace switch back on.
- Set the thermostat to call for heat. If the error code returns after 2-3 ignition attempts, the fault requires repair.
What does R4 mean?
The R4 error code on your York furnace indicates that the high limit switch has opened. This switch is a critical safety device designed to shut down the furnace if it gets too hot. Think of it like a circuit breaker for heat. When the furnace temperature exceeds a safe threshold, the high limit switch trips, cutting off the gas supply and blower motor. This prevents potential damage to the furnace components and, more importantly, protects your home from a fire hazard. The R4 code means the furnace control board detected that the switch is open (tripped). It's important to address the underlying cause of the overheating, not just reset the system.
Affected Models
Replacement Parts
| Part | OEM Number | Est. Cost |
|---|---|---|
| High Limit Switch | 024-36375-000 | — |
| Blower Motor Capacitor | — | — |
| Air Filter | — | — |
Related Codes on Same Models
| Code | Description | Severity |
|---|---|---|
| R1 | Flame Without Call | Critical |
| R2 | Pressure Switch Stuck Closed | Warning |
| R3 | Pressure Switch Stuck Open | Warning |
| R5 | Rollout Switch Open | Critical |
| R6 | Gas Valve Failure | Critical |
| R7 | Ignition Lockout | Critical |
| R9 | Reversed Polarity | Critical |
| A4 | Improper Thermostat Wiring | Warning |
| AF | Low Flame Current | Critical |