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Daikin · Furnace troubleshooting

Control display blank, furnace dead - Daikin DR96TN/DD96TN

What is going on

The furnace does nothing and the 7-segment display on the integrated control module shows nothing (the troubleshooting chart lists this as LED status 'None').

Likely causes

  • No 115 V power to the furnace or no 24 V to the control
  • Blown fuse or tripped breaker
  • Failed integrated control module

Check in this order

  1. Warning: line voltage present - measure carefully.
  2. Check that 115 VAC power reaches the furnace: breaker, service switch and the blower door interlock switch (door must be closed or the switch held in).
  3. Measure 115 VAC at the control board line terminals and 24 VAC at the transformer secondary.
  4. If 24 VAC is present at the transformer but missing at R-C, the board fuse is open - find and fix the low-voltage short, then replace the fuse.
  5. Correct whatever tripped the breaker or blew the fuse before resetting.
  6. Power and fuse good but still no display replace the integrated control module.
  7. Note read the fault history (F10 menu, last 10 faults) before cutting power.

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 (DR96TN/DD96TN service), 2 Stage Troubleshooting Codes, p.28-29. 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.