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Section 15 System operation and Troubleshooting
2. Sensor
●
T3(
Outdoor coil temperature
) and T4(ambient temperature, heat pump only) see TABLE A
●
T5(compressor discharge temperature) and Tf(IPM radiator temperature) see TABLE B.
●
Pressure Transducer see TABLE C.
1. Control logic description
● The variable speed system adopts the same control communication command as that of common heat pump
and air condition unit , it is the 24V control command .
● The speed of compressor is controlled by outdoor unit itself according to the pressure transducer. Usually , to
ensure stable and adequate capacity, the speed will change according to the evaporating pressure in cooling
and according to the condensing pressure in heating , another, the pressure target may adjust automatically
based on the compressor operating so that the capacity can better meet the needs. It can choose the target
setting according to dehumidification and high capacity demands by manually adjusting the code.
3. Sensor description
A working T3 Sensor is required for:
● Operating protection (high temp./low temp.)
● Outdoor fan control(cooling)
● Defrost (heat pump only)
● Ambient temp forecast (Cooling only)
A working T4 Sensor is required for(Heat pump only):
● Operating condition permission
● Defrosting condition determination
● Outdoor fan control(heating mode, Heat pump only)
A working T5 Sensor is required for:
● Protection(high temp./low temp.)
● Outside Electronic Expansion Valve control (Heat pump only)
A working Tf Sensor is required for:
● Module temp. protection(high temp.)
A working Pressure Transducer (PT) is required for:
● Operating speed control
● Outside Electronic Expansion Valve control (Heat pump only)
● High pressure protection(heating mode, Heat pump only)
● Low pressure protection(cooling mode)
ON
OFF
1 2
3 4
SW4
SW4-2
SW4-3
Not used
SW4-4
OFF
ON
Normally cooling/heatin g
OFF
ON
Accelerated cooling/heatin g
Adaptive capacity output disable
Adaptive capacity output enabl e
SW4-1
Not used
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