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Furnace not paired with R-32 cooling - disable A2L function - Daikin DR96TN/DD96TN

What is going on

The DR96TN/DD96TN control ships with the R-32 (A2L) leak-mitigation function ON. If the furnace is used with a non-R-32 cooling system or no sensor is connected, the furnace will treat the missing sensor as a fault and go to fan-only mitigation.

Likely causes

  • A2L function enabled with no R-32 sensor connected
  • Cooling unit uses a refrigerant other than R-32

Check in this order

  1. Confirm what refrigerant the paired cooling unit uses.
  2. R-32 system make sure the R-32 sensor wire from the indoor coil is plugged into the furnace control board before startup; route it with the thermostat wires, away from the flue pipe, hot surfaces and sharp edges.
  3. Non-R-32 system press left/right until the display shows A2E, press center, select no, and press center to confirm.
  4. To test the mitigation function (R-32 systems only, no active faults): go to A2u, select yes. The furnace shows EAL, stops gas heat, energizes the ventilation and alarm outputs and runs the fan at maximum airflow. The test ends after 5 minutes, on any fault, or when A2u is set back to no.
  5. Optional field outputs VT IN/VT OUT are dry contacts for a ventilator and the A2L alarm terminal supplies 24 VAC; both are normally open and energize only during an R-32 fault/alarm.

Applies to: Daikin DR96TN (upflow/horizontal) and DD96TN (downflow/horizontal) two-stage 96% furnaces with 9-speed ECM motor, R-32 ready

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Source: Daikin RSD6612304, R-32 Information, p.7 and p.10; menu table p.26. Written in our own words; check the manual for your exact model.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.