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OK. That is first thing manual says to try. You will have to have service tech check system. Not customer friendly. Problem description is 24 volts not sensed at Y1 input of J1 connection on outdoor control board. Possible causes are Faulty Y1 connection on outdoor control board. Intermittent breaks in high voltage to outdoor unit. Check to see if you have a float switch tripped. Sometimes the installer will break Y1 to shut down outside unit incase of drain line stopping up.
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