RDS fast flash R-32 leak alarm (or system verification test)

What the control is telling you

Red LED on the A2L board flashing fast. Either the sensor is detecting R-32 right now, or a technician started the 5-minute verification test. During an alarm the board stops the thermostat call, runs the blower and turns off electric heat.

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

Likely causes

• Refrigerant leak at the indoor coil or nearby
• Verification test started (button pressed twice within 5 s)

Test and repair steps

1. Warning: If a leak alarm is active, do not open or turn off the unit; ventilate and keep ignition sources away.
2. If a verification test was started it ends by itself after 5 minutes, or press the button once to end it early.
3. For a real alarm, the sensor and board are working - locate the leak and repair it.
4. After repair, check system pressures and lines for leaks and confirm cooling and heating performance.

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 3 flashes R32 sensor communication fault
• RDS 4 flashes R32 sensor internal fault
• RDS steady on Delay mode after leak alarm or fault