Mitsubishi Heavy Industries SRK20ZG-S Tech Manual page 23

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(a) Operating conditions: When the outdoor air temperature sensor (Th5) is 22ºC or lower continues for 30 seconds while
(b) Detail of operation:
1 The lower limit of inverter command speed is set to C(D)rps and even if the speed becomes lower than C(D)rps, the
speed is kept to C(D)rps. However, when the thermo becomes OFF, the speed is reduced to 0rps.
2 The upper limit of control speed is set to A(B)rps and even if the calculated result becomes higher than that after fuzzy
calculation, the speed is kept to A(B)rps.
Upper limit Arps
ON
Lower limit Crps
0
(c) Reset conditions: When the either of the following condition is satisfied
1
When the outdoor air temperature sensor (Th5) becomes 25ºC or higher.
2
When the inverter command speed is 0rps.
(4) High pressure control
(a) Purpose: Prevents anomalous high pressure operation during heating.
(b) Detector: Indoor unit heat exchanger sensor (Th2)
(c) Detail of operation:
(Example) Fuzzy
Notes (1) When the indoor unit heat exchanger temperature is in the range of B~C ºC, the speed is reduced by 4 rps at each 20 seconds.
(2) When the indoor unit heat exchanger temperature is in the range of C~D ºC, the speed is reduced by 8 rps at each 20 seconds. When the temperature is D
ºC or over for 1 minute continuously, the inverter is stopped.
(3) When the indoor unit heat exchanger temperature is in the range of A~B ºC, if the inverter command speed is been maintained and the operation has
continued for more than 20 seconds at the same speed, it returns to the normal heating operation.
(4) Indoor blower retains the fan tap when it enters in the high pressure control. Outdoor blower is operated in accordance with the speed.
¡ Temperature list
RPSmin < 40(88)
40(88) < = RPSmin < 50(108)
50(108) < = RPSmin
Notes (1) RPSmin: The lower one between the outdoor unit speed and the command speed
Note (2) Values in ( ) are for Type 50.
outdoor speed is other than 0rps.
ON
Upper limit Brps
Lower limit Drps
3 22 25
Outdoor air temp.(°C)
After lapse of 20 sec. or over
After lapse of 20 sec. or over
After lapse of 20 sec. or over
A
Indoor unit heat exchanger temperature(˚C)
A
48 (48.5) 53 (55)
48 (44) 53 (50.5)
48.5 (39) 56 (45.5)
¡ Values of A, B, C, D
OFF
20, 25, 35 type
50 type
(3) (1)
4rps
(3)
lower limit
(3)
speed 20(35) rps
B
B C
55 (58)
55 (53)
58 (48)
20
- -
Upper limit
A B
40 60
50 60
(2)
8rps
(1) (2)
4rps 8rps
0rps
C D
Unit : ºC
D
58 (61)
58 (56.5)
61 (51.5)
Lower limit
C D
30 30
44 30