1 blink
Moderate
York · HVAC Systems (AC, Furnaces, Heat Pumps & Thermostats)
System Lockout
Quick Answer
Error code 1 blink on your York HVAC Systems (AC, Furnaces, Heat Pumps & Thermostats) means: System Lockout. This is usually fixable — see the step-by-step guide below.
Likely Causes
How to Fix It
1
Turn off furnace power for 60 seconds to reset the lockout condition
2
After reset, observe the LED for a different blink code that identifies the root cause
3
Check the ignition system including the igniter, flame sensor, and gas valve
4
Verify gas supply is on and pressure is adequate at the manifold
5
If lockout recurs after reset, a licensed HVAC technician should perform a full system diagnostic
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
Hot surface igniter
Flame sensor
Control board
Related Error Codes