Troubleshooting By Inferior Phenomena - Mitsubishi Electric PAA-A18AA1 Service Manual

11.4. Troubleshooting by inferior phenomena

Phenomena
(1) LED 2 on • When LED 1 on indoor controller board is also off.
indoor con-
troller 1. Power supply of rated voltage is not supplied to outdoor
board is off. unit
2. Defective outdoor controller circuit board
3. Power supply of 208~230V is not supplied to indoor unit
4. Defective indoor controller board
(2) LED 2 on • When LED 1 on indoor controller board is also blinking.
indoor con- Connection failure of indoor/outdoor unit connecting wire.
troller
• When LED 1 is lit.
board is
blinking.
1. Miswiring 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.
PAA-A18, 24, 30, 36, 42AA1/BA1/CA1
Cause
1.
2.
3.
4.
Check indoor/outdoor unit connecting wire for connection failure.
1. Check the connection of remote controller wires in case of twin or 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 LED 2 on indoor controller board.
• When LED 2 is blinking, check the short-cut of remote controller wires.
• When LED 2 is lit, connect remote controller wires again and: if LED 2 is blinking,
remote controller is defective; if LED 2 is lit, connection failure of remote controller
terminal block etc. has returned to normal.
49
Countermeasure
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 breaker.
• When AC 208~230V is detected.
– Check 2 (below)
Check the voltage between outdoor terminal block S1 and S2.
• When AC 208~230V is not detected. Check the fuse on outdoor controller
circuit board. Check the wiring connection.
• When AC 208~230V is detected.
– Check 3 (below)
Check the voltage between indoor terminal block S1 and S2.
• When AC 208~230V is not detected. Check indoor/outdoor unit connecting
wire for miswiring.
• When AC 208~230V is detected.
– Check 4 (below)
Check the fuse on indoor controller board. Check the wiring connection. If no
problem are found, indoor controller board is defective.
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