Topics:

• Why do the lights in a 648PRO sometimes go out and come back on?
• Clicking noise from a 648PRO with the lights turning off and on
• Does the 648PRO run a self-test by itself?
• Blinking or flickering lights in a 648PRO
• Relays clicking or clicking noise
• 648PRO turns on by itself

Answer:

The 648PRO model has a self-test capability programmed into the control board. This can be initiated by a service technician through the diagnostic menu, or the unit itself runs the self-test periodically without prompting. This is a normal operation of the controls.

• During the self-test, the control board tests the functions of the board and relays.
• The lights turn off and on, as will other components such as the fans and compressors.
• Clicking noises are audible from the relays on the board closing and opening.
• The self-test takes a couple minutes and then goes back to operating normally and can happen a few times a week or even about once a day.