Midea MSV1-09HRDN1-QC2, Service Manual

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9.3 Protection
9.3.1 Three Minutes Delay at restart for compressor.
9.3.2 Temperature protection of compressor top.
9.3.3 If the temperature of compressor top is too high(higher than 115
℃
and the Over-load Protector is cut, the units
stop. When the Over-load Protector restore and close(lower than 100
℃
), the compressor will restart( in this
case the compressor is restricted by Three Minutes Delay protection.
9.3.4 Temperature protection of compressor exhaust. If the exhaust temp. of compressor is higher than 115
℃
and
lasts for 5 seconds, the compressor stops and does not resume until the exhaust temp. is lower than 90
℃.
9.3.5 Inverter module Protection, Inverter module Protection itself has a protection function against current, voltage
and temperature. If these protections happened, the corresponding code will display on indoor unit LED.
9.3.6 Sensor protection at open circuit and breaking disconnection
9.3.7 Fan Speed is out of control. When Indoor Fan Speed is too low (lower than 300RPM for 60 seconds), the unit
stops and LED displays failure information and can’t return to normal operation automatically.
9.3.8 Cross Zero signal error warning. If there are 20 alternations of Cross Zero signals are incorrect, the unit stops
and LED displays failure information. After resuming, the motor rotates again. The spacing of Cross Zero signal
is 6-13ms.
9.3.9 Indoor fan delayed open function
9.3.10 For all modes, when the units are turned on, the indoor fan can operate 10 seconds after the action of louver.
9.3.11 Compressor preheating function.
1) 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.
2) Preheating mode:
A weak current flows through the coil of compressor from the wiring terminal of compressor, then the
compressor is heated without operation.
3) Preheating release condition:
If T4
＞
5
℃
or user turns on the machine and compressor runs, preheating function will stop.
9.3.12 Compressor heating cable
If outdoor temperature(sensed by outdoor thermostat) is lower than 5
℃
, the thermostat closes and compressor
heating cable begins to work. If outdoor temperature is higher than 15
℃
, the thermostat opens and compressor
heating cable stopping working.
9.4 Fan-Only Mode
9.4.1 Temperature setting function is disabled, and no setting temperature display.
9.4.2 In this mode, the action of louver is the same as in cooling mode.
9.4.3 The action of auto fan in fan-only mode is the same as auto fan in cooling mode with 24
℃
setting temperature.
T
1
–
2
4
medium
3.5
3.0
1.5
1.0
℃
high
low