Troubleshooting - Trane Mitsubishi Electric CITY MULTI Series Technical & Service Manual

9

TROUBLESHOOTING

9-1. HOW TO CHECK THE PARTS
Parts name
Room temperature Disconnect the connector then measure the resistance with a multimeter. (At the ambient temperature 50 to 86°F)
detection thermistor (TH21)
Pipe temperature detection
thermistor/liquid (TH22)
4.3 to 9.6 Ω
Pipe temperature detection
thermistor/gas (TH23)
Fan motor (MF) Refer to "9-1-3. DC Fan motor (fan motor/indoor controller board)".
Vane motor (MV) Measure the resistance between the terminals with a multimeter. (At the ambient temperature of 68 to 86°F)
WH
Red–Yellow (5–3, 0–8, 5–3, )–8)
MV
Red–Blue (5–1, 0–6, 5–1, )–6)
OG
Red–Orange (5–4, 0–9, 5–4, )–9)
RD
Red–White (5–2, 0–7, 5–2, )–7)
YE
BU
Drain pump (DP) 1 Check if the drain float switch works properly.
2 Check if the drain pump works and drains water properly in cooling operation.
3 If no water drains, confirm that the check code 2502 will not be displayed 10 minutes after the operation starts.
Note: The drain pump for this model is driven by the internal DC motor, so it is not possible to measure the
1
RD
2
VT
3
BK
Normal
Red–Black: Input 13 VDC → The pump motor starts to rotate.
Purple–Black: Abnormal (check code 2502) if it outputs 0–13 V square wave (5 pulses/rotation), and the number of rotation is not normal.
Drain float switch (FS) Measure the resistance between the terminals with a multimeter.
Moving part
State of moving part
1
2
3
4
3D i-See sensor Turn the power ON while the i-See sensor connector is connected to the CN4Z on indoor controller board.
A communication between the indoor controller board and i-See sensor board is made to detect the connection.
Normal: When the operation starts, the motor for i-See sensor is driven to rotate the i-See sensor.
Abnormal: The motor for i-See sensor is not driven when the operation starts.
Note: The voltage between the terminals cannot be measured accurately since it is pulse output.
4 3 2 1
4 3 2 1
i-See sensor motor (MT) Measure the resistance between the terminals with a multimeter. (At the ambient temperature of 68 to 86°F)
(Option)
WH
M
OG
RD
YE
BU
Linear expansion valve Disconnect the connector then measure the resistance with a multimeter. (At the coil temperature 50 to 86°F)
(LEV)
CN60
WH
1
YE
2
OG
3
LEV
BU
4
RD
5
BN
6
OCHT746A
Normal Abnormal
Open or short
Connector
resistance between the terminals.
Normal
UP Short
DOWN Open
Connector Normal
Red–Yellow
Red–Blue
250 Ω
Red–Orange
Red–White
Connector Normal
White–Red
Yellow–Brown
200 Ω ± 10%
Orange–Red
Blue–Brown
Checkpoints
Refer to "9-1-1. Thermistor".
Normal Abnormal
300 Ω Open or short
Abnormal
Other than short
Other than open
Abnormal
Open or short
Abnormal
Open or short
Refer to "9-1-2. Linear expansion valve".
31
Switch
Magnet
Moving
Part