R-32 INFORMATION
This furnace is equipped with a control board that is capable of shutting off the gas heat and turning on the blower fan in case of an R-32 refrigerant leak in the indoor evaporator coil. If the cooling unit that is paired with this furnace does not utilize R-32 as the refrigerant, the R-32 functionalities in the furnace control board will need to be turned off for the furnace to run properly. R-32 function on the control board is ON by default. The R-32 function can be disabled through the furnace control by entering the A2L Function Enabled menu and selecting “no”. If A2L function is disabled, the furnace control will ignore all A2L functions. If A2L function is enabled, the control will monitor the R-32 sensor information. To enter the A2L Function Enabled menu, press the left or right button until LED displays “A2E”. Press the center button and the LED will display the selected option (yes or no). Press the left or right switch to select one of the two options and press the center button twice to confirm the option. Lastly, cycle power to the furnace.
Lastly, cycle power to the furnace
R-32 Sensor Wire Routing IMPORTANT NOTE: Wiring routing must not interfere with circulator blower operation, filter removal or routine maintenance. Wire should not be routed near hot surfaces and should be protected from sharp edges.
The R-32 Sensor wire coming from the indoor evaporator coil will need to be routed into the furnace and connected to the connection point on the furnace control board. This wire should be routed alongside the thermostat wires through the low voltage openings in the left or right side of the furnace blower compartment. Please see the electrical section for the location of the R-32 Sensor connection on the control board.
The R-32 function on the furnace control board may need to be enabled or disabled if any element of the installation changes from the original setup. The specific scenario will depend on each installation, so please refer to the evaporator coil’s installation manual to verify what is required for your setup. For example, if the furnace was initially installed with an evaporator coil that utilized R-410A refrigerant, and the coil is later replaced with one that uses R-32 refrigerant, then R-32 function mode on the furnace control board must be enabled, and the R-32 sensor wire must be connected to the furnace control board.
Furnace Start-Up
During furnace start up, the furnace control will identify the connected R-32 sensor and will start monitoring the sensor communication. A green LED located next to the sensor connection will indicate if there is communication between the furnace control and the R-32 sensor. The LED will be ON during the duration of the startup and then will either start blinking or turn OFF. The blinking LED signifies that communication with the R-32 sensor is present. The LED OFF signifies that there is no signal with the sensor. If there are no alarms or faults, the furnace will go into regular run mode after a warm up period. The furnace control monitors the R-32 sensor once per second.
R-32 Refrigerant Leak
If the R-32 sensor on the indoor evaporator coil detects a specified concentration of R-32 refrigerant, the furnace will enter Mitigation Mode to dilute the refrigerant concentrations in case of a leak. In Mitigation Mode, the furnace will do the following:
- Display the A2L Refrigerant Leakage error code (EAL)
- Shut down the gas operation
- Energize the optional ventilation and alarm outputs
- Run the fan at max CFM airflow
Once the R-32 sensor stops detecting a leak, the fan will continue to run for 5 minutes. After the 5 minutes, if there are no other alarms or faults, the control will de-energize the optional ventilation and alarm outputs and then go back to the original operating mode per the thermostat.
A2L Verification
The A2L Function Verification menu allows the installer to verify if the R-32 function operates properly. This menu simulates the refrigerant leak process and is only able to be used when there are no active alarms or faults. To verify the R-32 functions, enter the A2L Function Verification menu and select “YES”. To enter the A2L Function Verification menu, press the left or right button until LED displays “A2u”. Press the center button and the LED will display the selected option (yes or no). Press the left or right button to select one of the two options and press the center button twice to confirm the option. Once “YES” is selected, the furnace will do the following:
- Display the A2L Refrigerant Leakage code (EAL)
- Shut down the gas operation
- Energize the optional ventilation and alarm outputs
- Run the fan at max CFM airflow
The control will exit the verification function if:
- The 5 minute timeout expires or
- An alarm or fault is detected or
- The user turns OFF the A2L Function Verification.
NOTE: To verify gas heating operation shuts down, give furnace a call for heat before entering into A2L Function Verification.
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