Aprilaire dehumidifier control displays CL, and the unit will not dehumidify.

Safety first: No internal electrical work is required for this step; do not open the cabinet.

• Unlock the control: On most Aprilaire dehumidifiers, press and hold the UP and DOWN arrow buttons simultaneously for 3–5 seconds until CL disappears. On some wall controls, hold the MODE and DOWN buttons together.
• Check operation: After unlocking, adjust the humidity setpoint and verify that the unit responds (compressor and fan start when humidity is above the setpoint).
• Power cycle if needed: If CL remains, unplug the dehumidifier or turn off its breaker for 2 minutes, then restore power and repeat the unlock sequence.