Troubleshooting Problems Using The Led Status Indicators On The Outdoor Unit - Mitsubishi Electric R410A Service Handbook

[8-16 Troubleshooting Problems Using the LED Status Indicators on the Outdoor Unit ]

8-16 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](page 151)
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](page 288)
[8-12-2 Troubleshooting Problems with Outdoor Unit Transmission Power Supply Circuit](page 292)
(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 connectors 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 disconnected.
1) Wiring failure between the control board and the transmission line power supply 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. [9-1-2 Initial LED Display](page 302)
HWE14080 - 298 - GB