Sharp AE-X4M30PU, Service Manual

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AE-X4M30PU
5. SERIAL SIGNALS
Serial signals consist of all 96-bit signals. If the condition as outdoor unit unable to receive a serial signal from the indoor unit
continues for 30 seconds, it closes the expansion valve which corresponds to the room which can not be communicated. If all
indoor units can not communicate with the outdoor unit, the compressor is stopped.
6. THERMISTOR OPEN OR SHORT
When compressor, heat exchanger, outdoor thermistor, suction thermistor (CN8A) are in OPEN or SHORT condition, even if they are
in the condition which an operation signal is transmitted from indoors, the compressor will not start. If any suction thermistors (CN8M)
become OPEN or SHORT resistance, the protective procedure will work only for the cycle corresponding to the malfunctioning suction
thermistor.
7. MISWIRING CHECK
“Mis-wiring check” is conducted by detecting the indoor heat exchanger temp. For example, when the expansion valve for only room
A is open, and the wiring is correct, the indoor heat exchanger temp for room A will reduce. If the wiring is incorrect, the indoor heat
exchanger temp for a different room will reduce.
8. SAFETY TIME
When the unit is operated by the remote control after the breaker is turned on, the safety device of the compressor will work and the
compressor will not operate for 90 seconds.
9. PUMP DOWN SWITCH
When the PUMP DOWN SWITCH (SW1) is pressed for 5 seconds or more, the total A/C system will start its PUMP DOWN
automatically and the compressor frequency will be 40 Hz.
10. CONTROL OF COMPRESSOR AND EXPANSION VALVE
For 90 seconds after turning on the AC power, the compressor will not be activated even if indoor units request the compressor to
do so. If the compressor receives a request from one or more indoor units after 90 seconds have passed, it will be turned on and the
expansion valve corresponding to the requesting indoor unit will be opened. When the indoor unit of a room requests for the cooling
operation to the outdoor unit and it runs responding to the request, requests for the heating can’t be accepted if the indoor units in
other rooms send individual requests. If the indoor unit in another room sends a request for the heating operation, the operation lamp
and timer lamp of the indoor unit in that room start flashing in turn to inform that the unit is in the standby mode. If the operation in
one room is stopped while the indoor unit in another room is in the stand-by mode, the operation mode requested by the indoor unit
which is now in the stand-by mode will be accepted. At this time, the compressor will be temporarily stopped to switch the four- way
valve and restart after 90 seconds. During the cooling or dry operation, the expansion valve corresponding to the indoor unit that is not
running is closed. Therefore, the refrigerant will not flow into those units. However,if the heating operation is in progress, it is possible
that it flows into indoor units which are out of operation depending on the cycle conditions. As a result, the indoor exchanger may be
heated up even if it is not activated. This is not abnormal. When the operations in all rooms are stopped, the compressor is off and the
expansion valves in all rooms are fully opened.
11. DEFROST OPERATION
1) Overview
Defrosting begins during heating if the conditions for compressor
operation time and outdoor heat exchanger temperature are
met. When defrosting begins, the indoor and outdoor fans stop.
Defrosting stops when the temperature of the outdoor heat
exchanger goes above approximately 59°F (15°C) or defrosting
time exceeds 10 minutes.
Defrost
mask time
Defrost
mask time
Defrost
mask time
Heating
begins
Defrosting
Max. 10 min.
Defrosting
Max. 10 min.
2) Defrosting
If the compressor operation time is more than 20 minutes in
the heating mode and the outdoor air temperature and outdoor
heat exchange temperature satisfy the defrosting conditions, the
defrosting operation is started. When the defrosting operation
is started, the indoor fan s tarts to run intermittently. When the
outdoor heat exchanger temperature reaches approx. 59°F (15°C)
or above or when the defrosting time exceeds 10 minutes, the
defrosting operation is quit.
More than
20 min.
More than
20 min.
Defrosting
Max. 10 min.
Heating
operation
start
Defrosting
Max. 10 min.
More than
20 min.