2WAY VRF SYSTEM
Control Functions
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5. Outdoor Unit Fan Control
2WAY VRF SYSTEM
Control Functions
5. Outdoor Unit Fan Control
(2) Fixed Initial Fan Mode
For the first 30 seconds after operation starts, the mode is fixed at the initial mode which was calculated from the
relationship between the outdoor air temperature and the outdoor unit horsepower.
If the outdoor unit horsepower (compressor capacity) changes dramatically, the initial mode may be recalculated
and may be again fixed for 30 seconds.
(3) Operation after Fixed Initial Fan Mode
After the fixed initial fan mode, the fan mode is increased or decreased according to the operating conditions.
3-1. Cooling operation
* The fan mode is always increased when the detected high pressure sensor temperature is 114.8°F (46°C) or
higher.
Fan mode is increased when the detected high pressure saturated temperature is high, and is decreased when
the high pressure saturated temperature is low.
The fan mode may be decreased when the system detects refrigerant shortage at an indoor unit.
During cooling operation, if the fan mode becomes “0” and this condition maintains for 3 minutes, the fan mode is
changed to “1”.
3-2. When all indoor units are operating in heating mode
If the pressure sensor temperature is low, the fan mode is increased at regular intervals.
If the pressure sensor temperature is high, the fan mode is decreased in order to prevent excessive loads.
The fan mode may be increased when the liquid temperature of outdoor unit heat exchanger drops to
1.8deg F (1deg C) or below.
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18/06/19 18:55:32
