Daikin FTXA20A - Page 117

2 | Components
Service manual
117
FTXA20~50A(W)(S)(T) + FTXA20~50B(B)(S)(T) + RXA42+50A +
RXA20~35A(9) + RXA42+50B
Split Stylish R32
ESIE18-03D – 2021.05
DC fan motor resistance measurements
are correct?
Action
Yes Continue with the next step.
No Replace the DC fan motor, see "Repair
procedures"[4118].
9 Turn ON the power of the unit.
10 With the DC fan motor connector S70 disconnected from the inverter PCB,
measure the voltage on the connector pins 4-7 (= fan motor power supply) on
the inverter 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
inverter PCB.
Result: The voltage MUST be 15±10%VDC.
Are both measured voltages correct? Action
Yes Continue with the next step.
No Perform a check of the inverter PCB,
see "2.11.1Checking
procedures"[489].
12 Measure the voltage on the DC fan motor connector S70 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? Action
Yes Perform a check of the inverter PCB, see
"2.11.1Checking procedures"[489].
No Continue with the next step.
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?
Action
Yes Perform a check of the main PCB, see
"Checking procedures"[491].
No Replace the DC fan motor, see "Repair
procedures"[4118].
Problem solved?
After all checking procedures listed above have been performed:
Is the problem solved? Action
Yes No further actions required.