"Cool" Position For Outdoor Air Unit; "Heat" Position For Outdoor Air Unit - Fujitsu Airstage VR-II Series Service Manual

3-2-5 "COOL" Position for Outdoor air unit

When using the cooling mode, set the temperature to a value lower than the discharge airflow temperature, otherwise
the outdoor air unit will not start the cooling operation and only the fan will rotate.
An example for COOLING TEMPERATURE CONTROL time chart (Manual setting)
Outdoor temp.
Discharge airflow
Ts
Temperature
Ts - 9°F
(Ts - 5°C)
Refrigerant
ON
flow OFF
100%
Opening of
0%
EEV
ON
Outdoor air unit
OFF
fan
Ts : Corrected setting temperature

3-2-6 "HEAT" Position for Outdoor air unit

(1) When using the heating mode, set the temperature to a value higher than the discharge airflow temperature, otherwise
the outdoor air unit will not start the heating operation.
During defrosting, the OPERATION indicator lamp flashes 6 sec. ON and 2 sec. OFF, and repeat. The heating operation
(2)
will be temporarily interrupted.
An example for HEATING TEMPERATURE CONTROL time chart (Manual setting)
Ts +9°F
(Ts +5°C)
Discharge airflow
Temperature
Ts
Outdoor temp.
Refrigerant
ON
flow
OFF
100%
Opening of
0%
EEV
ON
Outdoor air unit
OFF
fan
Ts : Corrected setting temperature
Excess capacity area
Thermistor ON Thermistor OFF
(6 minutes) (3 minutes)
Thermistor ON
Thermistor OFF
(6 minutes)
(3 minutes)
5 minutes has passed
at excess capacity area
Thermistor ON
(6 minutes)
Ts + 1°F (Ts + 0.5°C) : The thres hold temperature of start of refrigerant flow
Ts - 9°F (Ts - 5°C) : The thres hold temperature of stop of refrigerant flow
Excess capacity area
Thermistor ON
(6 minutes)
Ts - 1°F (Ts - 0.5°C) : The thres hold temperature of start of refrigerant flow
Ts + 9°F (Ts + 5°C) for 5 minutes or more
: The thres hold temperature of stop of refrigerant flow
+1
03-07
5 minutes has passed
at excess capacity area