A051_F - Refrigerant Leak Sensor 1 Comm Fault
Status
This is a critical fault. Furnace has lost communication with the A2L sensing device
Description
A2L refrigerant sensor was previously detected by the board but is now missing or is not communicating. Furnace control declares this fault because it's unable to talk to the A2L refrigerant sensor. Clearing alarms or cycling power will not clear this fault.
Expected Operation
After detecting an A2L refrigerant sensor, if the furnace control losses communication with the sensor for more than 30 seconds, it declares this alarm. Cooling, heat-pump heating, and defrost operation is inhibited until the alarm condition goes away. Gas heating maybe permitted. Circulating blower airflow will be as appropriate for an A2L refrigerant leak event. If sensor communication is restored, alarm will be cleared and control will resume normal operation after a 5 minute delay.
Cause
1. Faulty A2L refrigerant leak detection sensor.
2. A2L refrigerant leak detection sensor is not getting power.
3. Communication lines between the sensor and the furnace control are bad/broken.
4. Sensor got removed because the indoor coil was replaced.
5. Faulty furnace control.
Solution
1. Replace A2L refrigerant leak detection sensor.
2. Check R and C power connections to the sensor. Verify 24VAC is present between R and C terminals on the sensor side.
3. Check E1/E2 wire for proper connection between the furnace control and the sensor. Do a short test on each wire to ensure the wires are not broken.
4. If the sensor has been removed and is indeed no longer needed, replace the furnace control. There is no way to make the furnace unlearn an A2L sensing device after it has been detected once.
5. Replace furnace control.
