Toshiba MMU-AP0181MH, MMU-AP0151MH, MMU-AP0091MH, MMU-AP0071MH, MMU-AP0121MH L18, L29, L20, L28

Check code name			Check code name		Cause of operation
[L18]		Flow selector unit system error		An indoor unit which has been operated in
				cooling only mode is operated in heating mode
				without setup for cooling only mode.
Did set up All cooling			NO		Set up All cooling mode.
					Item code (DN)=OF
to All cooling indoor unit?
					Cooling only operation mode=0001
	YES
					Check flow selector unit.

Check code name	Check code name		Cause of operation
[L29]	IPDU quantity error	1.	Incorrect model setup in service for I/F P.C.
			board
		2.	Communication error between IPDU, fan
			IPDU and I/F
		3.	IPDU, fan IPDU, I/F P.C. board error
Auxiliary code :
01: IPDU1 error	02: IPDU2 error
03: IPDU1, 2 error	04: Fan IPDU error
05: IPDU1, fan IPDU error	06: IPDU2, fan IPDU error

07: All IPDU error or disconnection of communication line between IPDU-I/F P.C. board or outdoor I/F P.C. board error

Check code name	Check code name	Cause of operation
[L20]	Duplicated central	Central control addresses are duplicated.
	control addresses

Is jumper setup of outdoor I/F P.C. board correct?		NO
(Jumpers 7, 8, 9 ON)
	YES
		YES
Is communication connector between IPDU and
I/F P.C. board connected?
	NO

Correct connection of connector.

Correct connection of connector.

Are not two or more	YES
central control system identical
network addresses connected?
NO

80

Correct the network address of the central control system.

Check the network adaptor on the indoor P.C. board.

Is there no disconnection of communication		YES
line between IPDU and I/F P.C. board?
	NO
Is there voltage fluctuation between		NO
4 and 5 pins of CN600 on I/F P.C. board.
(Measurement by tester: DC0 to 5V, 5 pin GND)
	YES

Replace communication line.

I/F P.C. board error

Check code name	Check code name		Cause of operation
[L28]	Quantity over of	1.	Quantity over of connected outdoor units
	connected outdoor units	2.	Connection error of communication line
			between outdoor units
		3.	Outdoor I/F P.C. board error

Is there voltage fluctuation between			NO	IPDU P.C. board error
3 and 5 pins of CN600 on I/F P.C. board.
(Measurement by tester: DC0 to 5V, 5 pin GND)
	YES	Both IPDU (No.1, No.2) and fan IPDU
		did not return the communication.

Is No. of connected		NO	Max. 3 units are allowed for flex system.
outdoor units below 3 units?
	YES
		NO
Is communication line between
			Correct connection of communication line.
outdoor units correctly connected?
	YES

Check outdoor I/F P.C. board.

On the fan power supply P.C. board,	NO
1) CN503: Between 1 and 5 pins 12V

2)CN503: Between 2 and 5 pins 7V

3)Between +5V and GND at the side of CN505: 5V

YES

Replace IPDU P.C. board with trouble.

Replace fan power supply P.C. board.

Auxiliary code	P.C. board to be replaced
01	IPDU1
02	IPDU2
03	IPDU1, 2
04	Fan IPDU
05	IPDU1, fan IPDU
06	IPDU2, fan IPDU
07	IPDU1, 2, fan IPDU, I/F