Daikin FTXC35A - Page 86

Refrigerant Diagram
78
6.8 Diode bridge short circuit check procedures
6.8.1 Power transistor check for class 25 & class 35
Check to make sure that the voltage between the terminal of Power transistor (+) and (-) is approx. 0
volt before checking power transistor.
<Measuring method>
Disconnect the compressor harness connector from the outdoor unit PCB. To disengage the
connector, press the protrusion on the connector.
Then, follow the procedure below to measure resistance between power transistor (+) and (-) and
the U, V and W terminals of the compressor connector with a multi-tester. Evaluate the measurement
results for a pass/fail judgment.
<Power transistor check>
Negative (-) terminal of
tester (positive terminal
(+) for digital tester)
Power transistor
(+)
UVW
Power transistor
(-)
UVW
Positive (+) terminal of
tester (negative terminal
(-) for digital tester)
UVW
Power transistor
(+)
UVW
Power transistor
(-)
Normal resistance SeveralkΩtoseveralMΩ(*)
Unacceptable resistance Short(0Ω)oropen
6.8.2 Main circuit short check for class 50 & class 60
Check to make sure that the voltage between (+) and (-) of the diode bridge (DB1) is approximately
0 V before checking.
• Measure the resistance between the pins of the DB1 referring to the table below.
• Iftheresistanceis∞orlessthan1kW,shortcircuitoccursonthemaincircuit.
Negative (-) terminal of
multimeter
- (2, 3) + (4) - (2, 3) - (1)
Positive (+) terminal of
multimeter
+ (4) - (2, 3) - (1) - (2, 3)
Resistance is OK
SeveralkΩ~
severalMΩ
∞ ∞
SeveralkΩ~
severalMΩ
Resistance is NG 0Ωor∞ 0 0 0Ωor∞
*Remark:
1. Use opposite sign of terminal for digital multimeter for measurement.
4
+
3
~
2
~
1
–
Multimeter