Daikin REYQ72-432XAYCU, Service Manual

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SiUS371901EB Check
Part 6 Service Diagnosis 444
Warning
Warning
Electrical Checks - Low Voltage Control Circuits
Line Voltage now present.
Motor Control/End Bell Checks
HIGH VOLTAGE!
Disconnect ALL power before servicing or installing. Multiple power sources may be present.
Failure to do so may cause property damage, personal injury or death.
6. Measure voltage between pins 5 and 3. Voltage should be approximately half of the
voltage measured in step 4.
7. If no voltage is present, check supply voltage to air handler or modular blower.
8. Disconnect power to air handler or modular blower. Reconnect the 5-circuit power
harness disconnected in step 2.
1. Turn on power to air handler or modular.
2. Check voltage between pins on the 4-wire motor control harness between the motor and
control board.
3. Voltage on pins should read:
Pins 1 to 4 = 3.3vdc
Pins 1 to 2 = 3.3vdc
Pins 3 to 4 = 15vdc
1. Disconnect power to air handler or modular blower.
NOTE: Motor contains capacitors that can hold a charge for several minutes after
disconnecting power. Wait 5 minutes after removing power to allow capacitors to
discharge.
2. Disconnect the motor control harness and motor power harness.
3. Remove the blower assembly from the air handler or modular blower.
4. Remove the (3) screws securing the control/end bell to the motor. Separate the
control/end bell. Disconnect the 3-circuit harness from the control/end bell to remove the
control/end bell from the motor.
5. Inspect the NTC thermistor inside the control/end bell. Replace control/end bell if
thermistor is cracked or broken.