Main Protection - Midea MSV1-12HRDN1-MQ0W Service Manual

9.3 Main Protection

9.3.1 Three Minutes Delay at restart for
compressor
1 minute delay for the 1
minutes delay for others.
9.3.2 Temperature protection of compressor
top
The unit will stop working when the compressor
top temp. protector cut off, and will restart after
the compressor top temp. protector restart.
9.3.3 Temperature protection of compressor
discharge
When the compressor discharge temp. is
getting higher, the running frequency will be
limited as below rules:
---Compressor discharge temp. T5>115℃ for
5s, compressor stops.
---108<T5<115℃, decrease the frequency to
the lower level every 3 minutes.
---90<T5<105℃, keep running at the current
frequency.
----T5<90℃, no limit for frequency.
9.3.4 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
9.3.5 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.
9.3.6 Indoor fan delayed open function
When the unit starts up, the louver will be active
immediately and the indoor fan will open 10s
later.
If the unit runs in heating mode, the indoor fan
will be also controlled by anti-cold wind
function.
9.3.7 Compressor preheating functions
Preheating permitting condition:
If T4(outdoor ambient temperature)＜3℃ and
the machine connects to power supply newly or
if T4＜3℃ and compressor has stopped for
over 3 hours, the compressor heating cable will
work.
st
time stand-up and 3
Preheating mode:
A weak current flow through the coil of
compressor from the wiring terminal of the
compressor, then the compressor is heated
without operation.
Preheating release condition:
If T4＞5℃ or the compressor starts running,
the preheating function will stop.
9.3.8 Zero crossing detection error
protection
If AC detects time interval is not correct for
continuous 240s, the unit will stop and the LED
will display the failure. The correct zero
crossing signal time interval should be between
6-13ms.
9.4.2.9 Condenser temperature protection
---55℃<T3<60℃, the compressor frequency
will decrease to the lower level until to F1 and
then runs at F1.If T3<54℃, the compressor will
keep running at the current frequency.
---T3<52℃, the compressor will not limit the
frequency and resume to the former frequency.
---T3>60℃ for 5 seconds, the compressor will
stop until T3<52℃.
9.4.2.10 Evaporator temperature protection
---T2<0℃, the compressor will stop and restart
>=
when T2 5℃.
---0℃≦T2<4℃, the compressor frequency will
be limited and decreased to the lower level
---4℃≤T2≤7℃, the compressor will keep the
current frequency.
---T2>7℃, the compressor frequency will not be
limited.
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