7-Segment Display Function - Carrier MMY-MAP0724FT9UL Service Manual

9-6. 7-Segment Display Function

7-segment display on outdoor unit (interface P.C. board)
The interface control P.C. board features a 7-segment LED display designed to check operational status.
Display items can be changed by changing the combination of the number settings of rotary switches provided
on the P.C. board (SW01, SW02 and SW03).
Interface P.C. board
Checking Procedure to Be Followed in Event of Abnormal Shutdown
If the system is shut down due to an error in the outdoor unit, perform checks in the following steps:
1
Open the panel of the outdoor unit and inspection window of the electric parts box, and
check the 7-segment display.
The check code is displayed in the right-hand section of the 7-segment display [B].
[U1] [OOO] ([OOO]: Check code)
* To check the check code, set the rotary switches SW01/SW02/SW03 to [1/1/1].
If there is a sub-code, the display alternates between the check code [OOO] (3 seconds) and the sub-
code [OOO] (1 second).
2
Check the check code and follow the applicable diagnostic procedure.
3
If the 7-segment display shows [U1] [E28], there is an error in a follower unit.
Push the push switch SW04 on the header unit and hold for several seconds.
As the fan of the outdoor unit in which the error has occurred comes on, open the panel of the unit, and
check the check code shown on the 7-segment display.
4
Perform checks in accordance with the diagnostic procedure applicable to the check code.
Push switch
7-segment display
[A]
– 184 –
SW04 SW05 SW15
D600 D601 D602 D603 D604
SW01 SW02 SW03
Rotary switches
7-segment display
[B]