Troubleshooting Using The Outdoor Unit Led Error Display - Mitsubishi Electric PUHY-P72 Service Manual

[ IX Troubleshooting ]

[7] Troubleshooting Using the Outdoor Unit LED Error Display

If the LED error display appear as follows while all the SW1 switches are set to OFF, check the items under the applicable item
numbers below.
1. Error code appears on the LED display.
Refer to IX [2] Responding to Error Display on the Remote Controller.
2. LED is blank.
Take the following troubleshooting steps.
(1) If the voltage between pins 1 and 3 of CNDC on the control board is outside the range between 220 VDC and 380 VDC,
refer to IX [4] -7- (2) Troubleshooting transmission power circuit of outdoor unit .
(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.(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 display appears as noted in "X [1] 2. LED display at Initial setting"(page 273) while the transmission cables
to TB3 and TB7 are disconnected, failure with the transmission cable or the connected equipment is suspected.
HWE0804A - 269 - GB