7-2-5. Control at HEAT Start-up
If HEAT operation is started when the outdoor air temperature is 15
°
C or below, the unit operates at the HEAT start-up
frequency (70 Hz or above).
Reset conditions
The compressor frequency exceeds the start-up frequency of (70 Hz).
The compressor thermostat is OFF.
Frequency reduction for indoor high-load control has occurred.
The outdoor air temperature is above 15
°
C.
The main-unit switch on one or more indoor units is set to TEST run.
(1)
(2)
(3)
(4)
(5)
(110)
(106)
(100)
Trip
5Hz every 30 sec. reduction
2Hz every 30 sec. reduction
No control
Increase
prohibit range
(Hz reduction)
(
°
C)
Compressor discharge temperature
(90)
Within the increase-prohibit range, the range changes
to the Hz reduction range (2 Hz every 30 seconds) if
the compressor temperature rises by 2
°
C.
*
Operation starts at (8 Hz), and the start current is less than the normal operating current. This prevents the flickering
of fluorescent lights or television screens that occurs when ordinary A/C units start.
7-2-3. Low Start Current
To protect the compressor coil from overheating, the operating frequency is controlled based on the compressor
discharge temperature.
7-2-4. Compressor Temperature Control
40
