Toshiba RAS-18YKH-E Service Manual page 24

Block level
Check Check
Block
code code
Indoor P.C.
board
Cable
connection
Refrigerant
system
Contents detected by the check codes
Therefore, contents of operations in the past are all displayed.
Table 9-2-4
Diagnosis function
Symptom
Indoor temp. (TA) sensor is
out of place.
Disconnection or short-circuit
Indoor temp. (TC) sensor is
out of place.
Disconnection or short-circuit
Trouble on indoor fan
Abnormal revolution speed of
fan
Indoor unit or other part is
defective.
EEPROM access error
Outdoor temp. sensor is out of
place.
Disconnection or short-circuit
Outdoor temp. sensor is out of
place.
Disconnection or short-circuit
Discharge temp. error
Detection of discharge temp.
over the set value
High-pressure switch
operation
IOL operation
Serial signal is not sent from
the outdoor unit to the indoor
unit.
• Miswiring of crossover wire
• Serial send circuit of the
outdoor P.C. board is
defective.
• Serial receive circuit of the
indoor P.C. board is
defective.
Trouble on the four-way valve
system
• After cooling operation has
started, the indoor heat
exchanger temp. rises.
• After heating operation has
started, the indoor heat
exchanger temp. lowers.
Trouble on other cycle line
• After cooling/heating
operation has started, the
indoor heat exchanger
temp. (TC) does not vary.
• When the compressor stop
command is sent by freeze-
preventing control.
Compressor break down.
to are stored in memory of the microcomputer even if the power supply is turned off.
– 24 –
Air
Conditioner Condition
status
Operation Displayed when
continues. error is detected.
Operation Displayed when
continues. error is detected.
All off Displayed when
error is detected.
Operation Displayed when
continues. error is detected.
All off Displayed when
error is detected.
All off Displayed when
error is detected.
All off Displayed when
error is detected.
All off Displayed when
error is detected.
Operation Displayed when
continues. error is detected.
Operation Displayed when
continues. error is detected.
Operation Displayed when
continues. error is detected.
Operation Displayed when
continues. error is detected.
Compres-
sor stops.
Indoor fan
LOW
All off Indicated when
detected
abnormal
Judgment and action
1. Check the indoor temp. sensor (TA).
2. Check the indoor P.C. board.
1. Check the indoor temp. sensor (TC).
2. Check the indoor P.C. board.
1. Check the connector circuit for
revolution speed input (CN13).
2. Check the indoor fan.
3. Check the indoor P.C. board.
1. Check the indoor P.C. board.
(EEPROM and peripheral circuits)
1. Check the outdoor temp. sensor (TE).
2. Check the P.C. board.
1. Check the outdoor temp. sensor (TD).
2. Check the P.C. board.
1. Check the refrigerating cycle
(Gas leak).
2. Check the pipe sensor (TD).
1. Check the high-pressure switch.
2. Check the circuits of high-pressure
switch line.
• Disconnection and contact failure of
CN04 connector
• Check the P.C. board.
3. Overload operation of the refrigerating
cycle
1. In case that the outdoor unit does not
operate at all,
• Check crossover wire./Correct
miswiring.
• Check the outdoor P.C. board.
2. In case that the outdoor unit operates
normally,
While the outdoor send Serial LED (Green)
on the indoor P.C. board flashes, If the
receive Serial LED (Orange)
Flashes : Check the indoor P.C. board.
Does not flash : Check the outdoor P.C. board.
1. Check the four-way valve.
2. Check the indoor heat exchanger
sensor (TC).
3. Check the indoor P.C. board.
1. Inner overload relay operation of
compressor case thermostat
(Electromagnetic contact OFF-STOP)
2. Indoor heat exchanger sensor sensing
part out of place
3. Check the indoor heat exchanger
sensor (TC).
4. Check the indoor P.C. board.
1. Check the charged amount of
refrigerant gas.
• Gas shortage →
Gas refilling, gas leak check
2. Check the indoor fan. (Lock)
1. Check compressor.
2. If it is OK, check P.C. board.