Panasonic U-4LE2E5 Service Manual & Test Run Service Manual page 23

4. Outdoor Unit Fan Control
5. Outdoor Unit Fan Control
(4) Fixed Initial Fan Step
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.
(5) Operation after Fixed Initial Fan Step
After the fixed initial fan step, the fan step is increased or decreased according to the operating conditions.
5-1. Cooling operation
Fan step is increased when the detected high pressure saturated temperature is high, and is decreased when
the high pressure saturated temperature is low.
* The fan step is always increased when the detected high pressure sensor temperature is 46°C or higher.
The fan step may be decreased when the system detects refrigerant shortage at an indoor unit.
During cooling operation, if the fan step becomes "0" and this condition maintains for 3 minutes, the fan step
is changed to "1".
5-2. When all indoor units are operating in heating mode
If the pressure sensor temperature is low, the fan step is increased at regular intervals.
If the pressure sensor temperature is high, the fan step is decreased in order to prevent excessive loads.
The fan step may be increased when the liquid temperature of outdoor unit heat exchanger drops to 1 degrees
Celsius or below.
(6) Silent Mode
Selecting the silent mode results in operation that gives priority to reducing noise at the outdoor unit.
When the setting is in silent mode, the outdoor fan step and the maximum frequency is limited.
So the capacity will be decreased. However, the frequency is not limited during the special controls.
Maximum fan step & maximum frequency in silent mode
Type of outdoor unit
Silent effect
Fan step
-1.5dB mode
Compressor frequency (Hz)
Fan step
-3dB mode
Compressor frequency (Hz)
Fan step
-5dB mode
Compressor frequency (Hz)
Fan step
-7dB mode
Compressor frequency (Hz)
4HP
Cooling Heating Cooling
9 11 10
63.0 63.0 79.0
8 10 8
43.8 48.6 51.8
7 8 6
43.8 48.6 51.8
6 7 6
43.8 43.8 48.6
1 - 13
2WAY VRF SYSTEM
Mini VRF SYSTEM
Control Functions
Control Functions - Outdoor unit
5HP 6HP
Heating Cooling
13 10
79.0 95.0
10 7
64.6 58.2
9 6
48.6 55.0
8 6
48.6 53.4
1
Heating
12
95.0
10
64.6
9
48.6
8
48.6