Fujitsu FO20R Series Installation Instructions Manual page 39

as the operating conditions remain within the safe
operating range of the compressor and inverter.
1. High voltage input (L1 – Black; L2 – Yellow)
2. Ground connection
3. Choke Connection
4. High Pressure control connection (HPS) – with
automatic reset
5. Discharge line thermistor connection (Sensor)
6. Modbus communication connections (RS485)
7. Compressor connections (W-Black; V-Red;
U-Yellow)
7.16 Suction Pressure Transducer
20 SEER heat pumps are equipped with a suction pressure transducer for
the purpose of measuring the suction pressure between the reversing valve
and the accumulator. The output of this device is a 0.5 – 4.5VDC signal
that the VSODC converts to a pressure used in calculating the heating
mode suction superheat. The measured suction superheat is used for
controlling the position of the outdoor EXV to maintain the correct heating
mode superheat level. The VSODC communicates the suction pressure
and heating mode superheat level to the Digital Control Center where they
are displayed on outdoor unit status screen.
7.17 Suction Temperature Thermistor
20 SEER heat pumps are equipped with a suction
line thermistor for the purposes of measuring suction
gas temperature during the heating mode. The
measured temperature is paired with the saturated
suction temperature and used by the VSODC to
calculate superheat and adjust the outdoor EXV to
maintain the correct superheat level.
Thermister Location
7.0 COMPONENTS & CONTROLS
IMPORTANT:
line thermistor securely attaches to the tube between
the outdoor coil and reversing valve. The thermistor
must be located between the 10 and 2 o'clock
position with a corrosion resistant stainless steel
clip. Insulation is factory installed over the suction
line thermistor and suction line. This thermistor is
provided with the coil thermistor as a single harness.
10 O'CLOCK
SUCTION
TEMPERATURE
THERMISTOR
The clamp on the suction
2 O'CLOCK
SUCTION
TEMPERATURE
THERMISTOR
TUBE
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