Mitsubishi Heavy Industries FDT28KXE6A Service Manual page 16

(6) Compressor pre-start control (Master unit/slave unit)
(a) The following control is performed when the compressor ON conditions are established.
(i) Pre-start control when the operation mode is same as previous operation mode:
1) In case of "Cooling /Dehumidifying" mode, 4-way valve is turned OFF. In case of "Heating" mode, 4-way valve
is turned ON.
However if the operation mode is same as previous operation mode and 4-way valve is retaing prescribed condi-
tion, the control status of 4-way valve is unchanged.
2) Solenoide valve SV6 and SV7 are turned ON.
3) The opening degree of EEVH1, 2 for heating and EEVSC for subcooling coil are set to the initial opening degree
mentioned in following table. The expansion valves EEVH1, 2 are operated first, and after those operations are
completed, the expansion valve EEVSC will be operated.
Note (1) Expansion valves of master unit and slave unit are operated respectively.
�Cooling � Heating
4) Fan motors FMo1, FMo2 and compressor start 15 seconds after the compressor ON conditions are satisfied.
Item Operation mode
Cooling
Name
EEVH1, 2 470
32
EEVSC
Cooling
FM 1,2
O
20S OFF
SV6
3 minutes
EEVH1,2 470
Full-close or 100
pulse
EEVSC Opening degree control
CM1 ON
OFF
CM2 ON
OFF
Min. of 3 minutes
Compressor stop
Starting conditions are satisfied
(Unit: Pulse)
Heating
10
0
Heating
OFF
ON
Initial opening degree
Full-close
15 seconds 6 seconds
Compressor start
14
- -
ON
ON
3 minutes
Open/close control
Opening degree control