Panasonic U-72MF2U9 Service Manual page 30

5. Outdoor Fan Control
5-2. 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 ambient temperature and the outdoor unit horsepower.
If the outdoor unit horsepower changes dramatically, the initial mode may be recalculated and may be again fixed
for 30 seconds.
5-3. Operation after Fixed Initial Fan Mode
After the fixed initial fan mode, the fan mode is increased or decreased according to the operating conditions.
5-3-1. Cooling mode at all indoor units, or else mixed heating/cooling operation when outdoor unit is functioning
as condenser
(1) Fan mode is increased when the pressure sensor temperature is high, and is decreased when the pressure
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sensor temperature is low.
* The fan mode is always increased when the pressure sensor temperature is 114.8°F (46°C) or higher (in the
case of all cooling mode).
* The fan mode is always increased when the pressure sensor temperature is 123.8°F (51°C) or higher (in the
case of mixed cooling/heating operation).
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* The fan mode is always increased when Maximum discharge temperature of inverter compressor in whole
system < High pressure sensor temperature +18deg F (+10deg C).
5-3-2. Heating mode at all indoor units, or else mixed heating/cooling operation when outdoor unit is functioning
as evaporator
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(1) If the condensation temperature is low, the fan mode is increased at regular intervals.
(2) If the condensation temperature is high, the fan mode is decreased in order to prevent excessive loads.
(3) The fan mode may be increased when the outdoor liquid temperature drops to 44.6°F (7°C) or below.
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3WAY VRF SYSTEM
Control Functions