Kaisai KMK-60RY1, Service Manual

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M thermal Split
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L0 troubleshooting 4.21.6
Situation 1: L0 error appears immediately after the outdoor unit is powered-on
L0
Communication wire between refrigerant
system main control board for refrigerant
systemnd inverter module (4 pins) not
connected properly
1
Yes
Ensure communication wire is connected
properly
No
Inverter module is damaged
2
Yes
No
Voltage between pins F0 and GND of
communication port for connection to
inverter module on the refrigerant
system main PCB is too low
3
Yes
Replace the inverter module
4
Notes:
1. For MHC-V12(14,16)W/D2RN8-B, the communication port between refrigerant system main control board for refrigerant system inverter module is port
CN36 on refrigerant system main control board for refrigerant system port CN8 on inverter module.
2. Measure the resistance between each of U, V and W and each of P and N on the inverter module. All the resistances should be infinite. If any of them are
not infinite, the inverter module is damaged and should be replaced.
3. The normal voltage between F0 and GND is 5V. Refer to Figure 4-4.6.
4. When replacing an inverter module, a layer of thermally conductive silica gel should be painted on the IPM module (on the reverse side of the inverter
module PCB). Refer to Figure 4-4.2.
Figure 4-4.6: F0 and GND voltage on IC28-1
（
F0
），
IC28-4
（
GND
）
Vnormal = 5V
IC28-1
（
F0
）
IC28-4
（
GND
）
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Situation 2: L0 error appears immediately after the compressor starts up
L0
DC bus wire is not connected properly
1
Yes
Ensure DC bus wire is connected properly
No
Compressor has malfunctioned
2
Yes
Replace the compressor
No
Replace the main PCB
Notes:
1. The DC bus wire should run from the N terminal on the inverter module, through the current sensor (in the direction indicated by the arrow on the current
sensor), and end at the N terminal of capacitor. Refer to Figure 4-4.7.
Figure 4-4.7: DC bus wire connection
（
L1L2L3,PIN- POUT
）
L1
，
L2
，
L3 Pin
，
Pout
2. The normal resistances of the inverter compressor are 0.7-1.5Ω among U V W and infinite between each of U V W and ground. If any of the resistances
differ from these specifications, the compressor has malfunctioned.
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