[7] OUTDOOR UNIT CHECK METHOD
After repairing the outdoor unit, conduct the following inspection procedures to make sure that it has been repaired completely. Then,
operate the compressor for a nal operation check.
1. Checking procedures
No.
Item Check method Normal value/condition Remedy
1
Preparation Disconnect compressor cords (white, orange,
red: 3 wires) from compressor terminals, and
connect simulated load (lamp used as load).
Operate air conditioner in cooling or heating
test operation mode.
2
Inverter DC power
supply voltage
check
Measure DC voltage between IPM pins (20)
and (24).
320 VDC Replace control PWB.
Replace diode bridge.
Correct soldered section of Fasten
tabs (BT1,2,5,6,10,11, JPL1,2,5,6)
on control PWB.
(Repair solder cracks.)
3
IPM circuit check Check that 3 lamps (load) light.
Check position detection voltage (+15 V, 5 V)
on control PWB.
Each voltage should be normal.
All 3 lamps (load) should light with
same intensity.
Replace control PWB.
4
Compressor check Measure compressor coil resistance
(for each phase of U, V and W).
Use multi-meter or digital tester capable
of displaying two digits right of the decimal
point (0.01Ω).
Resistance value at 20
℃
--- 0.65Ω Correct connections at compressor
terminals.
Replace compressor.
5
Expansion valve
check
Measure expansion valve coil resistance. Each phase 46±3Ω (at 20
℃
) Replace expansion valve.
6
Final check Turn off power, and connect compressor
cords to compressor.
Operate air conditioner.
Measure DC voltage between IPM pins (20)
and (24).
Compressor should operate
normally.
320 VDC or higher.
Replace control PWB.
Replace outdoor unit thermistor.
Replace compressor (in case of
compressor lock).
2. Troubleshooting of outdoor unit electric components
Does LED light?
NO
YES
NO
Does LED flash?
Normal
NO
YES
YES
NO
YES
NO
YES
Check 320VDC
between IPM pins
(20) and (24) ?
Short-circuit in DC fan motor
Short-circuit in IPM
Short-circuit in diode bridge
Blown fuse
Defective electrolytic capacitor
Wire disconnection, PWB pattern damage
Short-circuit in PAM IGBT (Q5)
Defective switching power supply circuit
Malfunction of 3-terminal regulator IC4, IC1
Short-circuit in expansion valve coil
Malfunction of transistor array IC7
Solder contact or other problems
Malfunction of 3-terminal regulator IC4, IC1
Microcomputer oscillator error
Malfunction of microcomputer reset IC
Malfunction of microcomputer
Malfunction of serial signal circuit
Check wiring between indoor and outdoor units.
Check switching
power supply
output of 12 VDC,
15 VDC ?
Check 5 VDC
output ?
Check 220-240VAC
input voltage.
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