Mitsubishi Electric PURY-HP144, Service Handbook

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[8-15 Troubleshooting Problems Using the LED Status Indicators on the Outdoor Unit ]
100
- chapter 8 HWE18220_GB
8 Troubleshooting Based on Observed Symptoms
8-15 Troubleshooting Problems Using the LED Status Indicators
on the Outdoor Unit
If the LED error display appear as follows while all the SW4 switches and SW6-10 are set to OFF, check the items under the ap-
plicable item numbers below.
1. Error code appears on the LED display.
Refer to the following page(s). [7-1 Error Code and Preliminary Error Code Lists]
2. LED is blank.
Take the following troubleshooting steps.
(1) Refer to the section on troubleshooting the transmission power supply circuit, if the voltage
across pins 1 through 3 of CNDC on the control panel is outside the range between 220 VDC
and 380 VDC. [8-11-2 Troubleshooting Problems with Outdoor Unit Transmission Power Supply
Circuit]
(2) If the LED error display becomes lit when the power is turned on with all the connectors on the
control board except CNDC disconnected, there is a problem with the wiring to those connec-
tors or with the connectors themselves.
(3) If nothing appears on the display under item (2) above AND the voltage between pins 1 and 3 of
CNDC is within the range between 220 VDC and 380 VDC, control board failure is suspected.
3. Only the software version appears on the LED display.
(1) Only the software version appears while the transmission cables to TB3 and TB7 are discon-
nected.
1) Wiring failure between the control board and PS board. (CN62, CNPS, CNIT, CNS2, CN102)
2) If item 1) checks out OK, the transmission line power supply board failure is suspected.
3) If items 1) and 2) check out OK, control board failure is suspected.
(2) If the LED shows the same display as the initial display upon disconnection of transmission
lines (TB3, TB7), there is a problem with the transmission lines or with the connected devices.
[10-1-2 Initial LED Display]