RDS 3 flashes R32 sensor communication fault

What the control is telling you

Red LED flashes 3 times, then off 5 s: the board cannot talk to the R32 sensor.

Applies to: R-32 air handlers with refrigerant detection system (A2L PCB + R32 sensor): AMST, AWSF/AWST, ACSF

Likely causes

• Faulty sensor
• Faulty sensor harness
• Fault inside the board

Test and repair steps

1. Unplug and reconnect the R32 sensor, then power cycle.
2. If the board returns to normal or delay mode, no further action.
3. If 3 flashes remain (with the connector properly seated), replace both the sensor and the board - the fault cannot be isolated further in the field.

Models that show this code

4 models in Goodman/Amana R-32 AMST/AWSF/ACSF air handlers

Other codes on the same units

• RDS 2 flashes Control board internal fault (leak detection board)
• RDS 4 flashes R32 sensor internal fault
• RDS fast flash R-32 leak alarm (or system verification test)
• RDS steady on Delay mode after leak alarm or fault