Function Of Soft Start Relay - Mitsubishi Electric MSC-CA20VB Service Technical Manual

2 When the temperature difference
RT13 in the indoor unit is 2: or more for a fixed time at cool or dry operation, the target discharge temperature is
changed. After the temperature is changed, when temperature difference
is changed again. The LEV opening is controlled based on the changed target discharge temperature and the temper-
ature difference
Ta (:)
more than Tb+10
Tb+5 to Tb+10
Tb+2 to Tb+5
Tb-2 to Tb+2
Tb-5 to Tb-2
Tb-10 to Tb-5
less than Tb-10
NOTE : Discharge temperature : Ta, Target discharge temperature : Tb
The target discharge temperature (Tb) is set according to the operation mode or the unit status as follows.
COOL (Normal)
COOL ( RT is less than 2:, or
COOL ( RT is 3 :or more.)
NOTE : Target discharge temperature : Tb
NOTE : When the discharge temperature (Ta) is 50: or less on the cool operation LEV opening is set in 54 pulse.
When this state continues for 20 minutes, the compressor is stopped and restarts in 3 minutes.
When the compressor is stopped, the indoor unit indicates the abnormality of refrigerant system and stops.
(OPERATION INDICATOR lamp is 10-time flashing on and off.)
(2) LEV time chart
Opening
Power ON
completely
Open
Remote
controller
ON
Initial opening
Positioning
Close
NOTE : Opening increases and decreases to be in the target discharge temperature during operation.

2-10. FUNCTION OF SOFT START RELAY

Soft start relay will chop some starting current.
Starting current is reduced as shown in the following figures.
RT between indoor coil thermistor (main) RT12 and indoor coil thermistor (sub)
RT.
less than 2:
20
10
2
0
-2
-5
-10
Operation mode
RT is 2:or more and less than 3:.)
Thermostat
Operation OFF
Standard opening Thermostat
ON
Opening in stop
(A)
WITHOUT SOFT START RELAY
WITH SOFT START RELAY
2: or more and less than 3:
Remote
controller
Operation
OFF
Standard opening
Initial opening
Opening in stop
(Second)
25
RT is 3: or more, the target temperature
RT
3: or more
60
20
2
0
-2
-5
-10
Tb (:)
80
70
65
Remote
Opening
controller
completely
ON
Standard opening
Initial opening
Positioning
60
20
2
0
-2
-5
-10
Operation
Time