Troubleshooting By Inferior Phenomena - Mitsubishi Electric TRANE NTXAMT12A112AA Service Manual

12.4. Troubleshooting by inferior phenomena

Phenom-
ena
(1) LED2 • When LED1 on indoor controller board is also off.
on indoor
controller 1. Power supply of rated voltage is not supplied to
board is outdoor unit
off.
2. Defective outdoor controller circuit board
3. Power supply of 208~230V is not supplied to
indoor unit
4. Defective indoor controller board
(2) LED2 • When LED1 on indoor controller board is also
on indoor blinking. Connection failure of indoor/outdoor unit
controller connecting wire.
board is
• When LED1 is lit.
blinking.
1. Mis-wiring of remote controller wires Under twin
triple indoor unit system, 2 or more indoor units
are wired together.
2. Refrigerant address for outdoor unit is wrong or
not set. Under grouping control system, there
are some units whose refrigerant address is 0.
3. Short-cut of remote controller wires 4 Defective
remote controller.
Specifications are subject to change without notice.
NTXAMT12, 18, 24, 30, 36A112AA
Cause
1. Check the voltage of outdoor power supply terminal block (L, N) or (L3, N).
• When AC 208~230V is not detected. Check the power wiring to outdoor unit and the
• When AC 208~230V is detected.
2. Check the voltage between outdoor terminal block S1 and S2.
• When AC 208~230V is not detected. Check the fuse on outdoor controller circuit
• When AC 208~230V is detected.
3. Check the voltage between indoor terminal block S1 and S2.
• When AC 208~230V is not detected. Check indoor/outdoor unit connecting wire for
• When AC 208~230V is detected.
4. Check the fuse on indoor controller board. Check the wiring connection. If no problem
are found, indoor controller board is defective.
Check indoor/outdoor unit connecting wire for connection failure.
1. Check the connection of remote controller wires in case of twin triple indoor unit system.
When 2 or more indoor units are wired in one refrigerant system, connect remote controller
wires to one of those units.
2. Check the setting of refrigerant address in case of grouping control system. If there are
some units whose refrigerant addresses are 0 in one group, set one of the units to 0 using
SW1 (3-6) on outdoor controller circuit board.
3~4. Remove remote controller wires and check LED2 on indoor controller board. • When
LED2 is blinking, check the short-cut of remote controller wires. • When LED2 is lit, connect
remote controller wires again and: if LED2 is blinking, remote controller is defective; if LED2 is
lit, connection failure of remote controller terminal block etc. has returned to normal.
50
Countermeasure
breaker.
– Check 2 (below)
board. Check the wiring connection.
– Check 3 (below)
mis-wiring.
– Check 4 (below)
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