Troubleshooting (Continued)

Check code

Check code name

Possible causes

 

 

 

[E04]

I/U - O/U communication error

AImproper connector connection between I/U and O/U

(New code)

(detected by I/U)

BImproper wire connection between I/U and O/U

 

 

CFailure of I/U or O/U board

 

 

DCase thermo sensor ON

 

 

EInvalid I/U board switch setting

 

 

 

NO

Does O/U work?

YES

Check I/U boards.

→Replace defective board.

Is group address set correctly?

NO

 

YES

 

 

Are 1/2/3 wires normal?

NO

 

YES

 

 

Are connectors from I/U and

NO

 

O/U connected normally?

 

YES

 

 

Is I/U switch SW02

 

NO

setting correct? Bit 1, 2: OFF

 

YES

 

 

Does voltage between

NO

I/U terminal 2 and 3 fluctuate?

 

(0-140 VDC)

 

 

* Measure within

YES

20 seconds

from power on.

Is 280VDC

 

NO

applied across IPDU main

 

circuit capacitor?

 

 

YES

 

 

Is 280VDC supplied to

NO

 

CDB? (CN03)

 

 

YES

 

 

Is 7VDC supplied

 

NO

to CDB? Is CN06-CN800

 

connection normal?

 

 

YES

 

 

Is case thermo sensor

NO

 

connected? (CN500)

 

 

YES

 

 

Is case thermo sensor working?

NO

 

YES

Check and correct refrigerant volume.

Check code “14”.

Correct wires.

Correct connector connection.

Correct switch setting on

MCC-1510 board.

Check MCC-1510 board.

→Replace it if necessary.

Black C

White B

A

Terminal block

Replace IPDU.

Replace IPDU.

Replace IPDU.

Correct connector connection.

Correct connector connection.

Check MCC-1510 board.

→Replace it if necessary. Check CDB. → Replace it if

necessary.

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