Mitsubishi Heavy Industries SRK20ZJ-S Technical Manual page 175

Reset conditions: When either of the following condition is satisfied
3)
a) The outdoor air temperature (TH2) is D ˚C or higher.
b) The compressor command speed is 0 rps.
(e) Heating high pressure control
Purpose: Prevents anomalous high pressure operation during heating.
1)
Detector: Indoor heat exchanger sensor (THI-R)
2)
3) Detail of operation:
(Example) Fuzzy
Notes (1) When the indoor 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 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 higher continues for 1 minute, the compressor is stopped.
(3) When the indoor heat exchanger temperature is in the range of A~B ºC, if the compressor 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 < 50
50 < = RPSmin < 95
95 < = RPSmin < 97
97 < = RPSmin < 104
104 < = RPSmin < 115
115 < = RPSmin
Note (1) RPSmin: The lower one between the outdoor speed and the compressor command speed
(f) Heating overload protective control
Operating conditions: When the outdoor air temperature (TH2) is 22ºC or higher continues for 30 seconds while the
1)
2) Detail of operation:
a) Taking the upper limit of compressor command speed range at 60 rps, if the output speed obtained with the fuzzy
calculation exceeds the upper limit, the upper limit value is maintained.
b) The lower limit of compressor command speed is set to 40 rps and even if the calculated result becomes lower than
that after fuzzy calculation, the speed is kept to 40 rps. However, when the thermo becomes OFF, the speed is re-
duced to 0 prs.
c) Inching prevention control is activated and inching prevention control is carried out with the minimum speed set at
40 rps.
d) The outdoor fan is set on 2nd speed.
e) The indoor fan is stepped up by 1 speed step.
Reset conditions: The outdoor air temperature (TH2) is lower than 21ºC.
3)
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 B
48 53
48.5 56
48.5 56 ~ 55.5
48.5 55.5 ~ 51.5
48.5 ~ 42.1 51.5 ~ 44
42.1 44
compressor command speed other than 0 rps.
4rps (1)
(3)
4rps
(3)
lower limit
(3)
speed 30 rps
B
C D
55 58
58 61
58 61
58 ~ 53.5 61
53.5 ~ 47.3 61
47.3 61
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8rps (2)
(1) 8rps (2)
0rps
C D
Unit : ºC