Toshiba MMU-P0121H Service Manual page 54

Check Detected Check code
code position name
bE Interface Low pressure
protective
operation
cF Indoor Communication
error between
indoor MCU
d1 Interface Outdoor
inverter set up
alarm
d2 Interface Fixed-speed
outdoor unit
alarm
d3 Inverter TH sensor
alarm
d4 Interface TK1 sensor
alarm
d5 Interface TK2 sensor
alarm
Cause
Trouble detection condition
(Position)
Protection Low pressure Ps detected
when low lower than 0.02MPa.
pressure Ps
lowered.
Communication between MCU
Lead wire
interrupted for 50 seconds.
between indoor
main P.C.
board (MCC-
1361) and
indoor motor
P.C. board
(MCC-1382)
Outdoor There were multiple outdoor
inverter units inverter units in 1 line.
are duplicated.
Fixed-speed Inverter outdoor unit received
outdoor unit an alarm code from fixed-
protection speed outdoor.
Temp. sensor Sensor resistance value was
(TH) to detect infinity or zero (Open, Short).
overheating of
IPDU
microprocessor
Temp. sensor Sensor resistance value was
(TK1) to detect infinity or zero (Open, Short).
oil level
Temp. sensor Sensor resistance value was
(TK2) to detect infinity or zero (Open, Short).
oil level
3-51
Check item (Position)
• Check for refrigerant shortage.
• Check outdoor service valves.
(Gas side, Liquid side are fully open.)
• Check for blockage of outdoor PMV.
1) Refrigerant choke circuit (PMV A)
2) Liquid line check valve
(Cooling only model)
• Check discharge temp. TD sensor
error.
• Check low pressure Ps sensor error.
• Check indoor filter blockage.
• Check refrigerant pipe blockage.
• Check outdoor fan operation.
(In heating)
• Check connection between connector
(CN28) of indoor main P.C. board
(MCC-1361) and connector (CN27) of
indoor motor P.C. board (MCC-1382).
• Check failure of indoor main P.C.
board (MCC-1361).
• Check failure of indoor motor P.C.
board (MCC-1382).
• Check No. of connected inverter
outdoor units.
• Check SW08/bit 2 set up on outdoor
P.C. board (interface).
• Check outdoor P.C. board (interface).
• Check the check code of fixed-speed
outdoor unit.
• Convenient functions
If keeping SW04 pushed for 5 seconds
or more under condition that [d2] is
displayed on the 7 segment display of
the inverter outdoor, fan of the outdoor
unit which stops in emergency
operates.
If keeping SW04 and SW05 pushed
concurrently, the normal outdoor unit
fan operates.
If pushing SW05 alone, the fan
operation is released.
• Temp. sensor incorporated with IGBT
has failed. → Replace IPDU P.C.
board.
• Check connector connection of TK1
sensor.
• Check characteristics of TK1 sensor
resistance value.
• Check outdoor P.C. board (interface)
error.
• Check connector connection of TK2
sensor.
• Check characteristics of TK2 sensor
resistance value.
• Check outdoor P.C. board (interface)
error.