Daikin FTXP20-71L Service Manual page 108

3 | Components
Problem solved?
Service manual
108
DC fan motor resistance measurements
are correct?
Yes
No
9 Turn ON the power of the unit.
10 With the DC fan motor connector S71 disconnected from the main PCB,
measure the voltage on the connector pins 4-7 (= fan motor power supply) on
the main PCB.
Result: The voltage MUST be 200~390 V DC.
11 Measure the voltage on the connector pins 4-3 (= fan motor control) on the
main PCB.
Result: The voltage MUST be 15±10% V DC.
Are both measured voltages correct?
Yes
No
12 Measure the voltage on the DC fan motor connector S71 pins 2-4 (= rotation
command) on the PCB.
Result: The measured voltage should be 0~7 V DC. It should NOT be 0 V DC.
Is the measured voltage 0 V DC?
Yes
No
13 Connect the DC fan motor connector to the PCB. Remove the plastic insert
from the connector for easier measurement.
CAUTION
Ensure that the system CANNOT start the fan. Disable all modes (heating, cooling, ...)
on the unit. The unit MUST be kept powered.
14 Manually (slowly) rotate the fan blade propeller 1 turn and measure the
voltage on the DC fan motor connector pins 1-4.
Result: 4 pulses MUST be measured.
Pulses are measured during fan blade
propeller rotation?
Yes
No
After all checking procedures listed above have been performed:
Is the problem solved?
Yes
Action
Continue with the next step.
Replace the DC fan motor, see
4
procedures" [ 109].
Action
Continue with the next step.
Perform a check of the main PCB, see
"3.7.1 Checking procedures" [
Action
Perform a check of the main PCB, see
"3.7.1 Checking procedures" [
Continue with the next step.
Action
Perform a check of the main PCB, see
"3.7.1 Checking procedures" [
Replace the DC fan motor, see
4
procedures" [ 109].
Action
No further actions required.
ATXP20~35 + FTXP20~71 + ARXP20~35 + RXP20~71
"Repair
4
84].
4
84].
4
84].
"Repair
Split Comfora R32
ESIE18-01E – 2023.01