Midea MOB31-12HFN1-QRD0GW, Service Manual

Page: 34 / 65

34
9.3 Main Protection
9.3.1 Three minutes delay at restart for
compressor
Less than 1 minute delay for the 1
st
time
start-up and 3 minutes delay for others.
9.3.2 Temperature protection of compressor
discharge
Compressor discharge temperature T5>115
℃
for 5s, compressor stops.
9.3.3 Fan speed is out of control
When indoor fan speed keeps too low
(300RPM) for certain time, the unit will stop and
the LED will display the failure
9.3.4 Inverter module protection
The Inverter module has a protection function
about current, voltage and temperature. If these
protections happen, the corresponding code
will display on indoor unit and the unit will stop
working.
9.3.5 Indoor fan delayed open function
When the unit starts up, the louver will be active
immediately and the indoor fan will open 7s
later.
If the unit runs in heating mode, the indoor fan
will be also controlled by anti-cold wind
function.
9.3.6 Compressor preheating functions
Preheating permitting condition:
When T4(outdoor ambient temperature)
＜
3°C,
the preheating function will be activated.
9.3.7 Sensor protection at open circuit and
breaking disconnection.
When there’s only one temperature sensor in
malfunction , the air conditioner will keep
working but show the error code, in case of any
emergency use.
When there’s more than one temperature
sensor in malfunction, the air conditioner will
stop working.
9.3.8 Refrigerant leakage detection
This function is only active in cooling mode. It
can better prevent the compressor being
damaged by refrigerant leakage or compressor
overload.
Open condition:
When compressor is active, the value of the
Coil temperature of evaporator T2 has no
change or very little change.