Outdoor Unit Control - Mitsubishi Electric PCH-2GKHA Service Manual

3. OUTDOOR UNIT CONTROL

3-1 Outdoor fan control
The rotational frequency of outdoor fan is phase-controlled according to the outdoor coil temperature. This control allows the
cooling operation even with the low outside-air temperature and the heating operation even with the high outside-air
temperature.
3-2 Outdoor unit control
The outdoor unit turns ON/OFF the cooling/heating operation according to orders given from the indoor unit.
3-3 Protective functions
1 If an reversed-phase, an open phase, or an indoor controller abnormality is detected, the outdoor unit will stop operation
and the check mode will start. (For the check mode details, see page 52.)
2 If a protective function works, the compressor will stop running. Three minutes later, the compressor will restart. If the
protective function works again, the compressor will stop running and the check mode will start.
3 The protective function is memorized.
4 The memory is cleared when the POWER ON/OFF button on the remote controller is turned OFF. However, the check
mode dispaly continues until the outdoor unit receives the "operation ON" command from the indoor unit.
3-4 COOL/HEAT operation time chart
Operation starts by
P O W E R b u t t o n ON.
ON
Thermostat
OFF
ON
Compressor
OFF
Crankcase heater
ON
(with jumper wire
OFF
J3)
Crankcase heater
ON
(without jumper
OFF
wire J3)
ON
4-way valve
OFF
(COOL)
ON
4-way valve
(HEAT)
OFF
ON
Bypass valve
OFF
ON
Outdoor fan
OFF
Room temperature
becomes equal to set
temperature.
w1 If compressor restarts within 10 minutes, 4-way valve remains ON.
Room temperature
becomes different from
set temperature.
60 minutes
60 minutes 60 minutes 60 minutes 60 minutes 60 minutes
10 minutes
3 minutes
Operation stops by
P O W E R b u t t o n OFF.
60 minutes
Repeats 60-minute
ON/OFF
10 minutes 1
3 minutes
45