Mitsubishi Heavy Industries SRK60ZSX-W, Service Manual

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25
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'19 • SCM-SM-276
(18) Protective control function
(a) Dew prevention control [Cooling]
Prevents dewing on the indoor unit.
(i) Operating conditions
When the following conditions have been satisfied for more than 30 minutes after starting operation
1) Detected value of humidity is 68% or higher.
2) The compressor is ON.
(ii) Contents of operation
1) Air capacity control
Model
Item
SRK20, 25ZS-W SRK35ZS-W SRK50ZS-W
Indoor fan
LO, ULO
4th speed 5th speed 4th speed
AUTO, HI, MED
Adaptable to compressor speed
(Lower limit 4th speed)
Adaptable to compressor speed
(Lower limit 5th speed)
Adaptable to compressor speed
(Lower limit 4th speed)
2) When this control has continued for more than 30 minutes continuously,the following wind direction control is performed.
a) When the vertical wind direction is set at other than the vertical swing,the flaps change to the horizontal position.
b) When the horizontal wind direction is set at other than the horizontal swing,the louver changes to the vertical position.
(iii) Reset condition
When any of following is satisfied.
1) Detected value of humidity is less than 63%.
2) The compressor is OFF.
'09•SRK-DB-087D
(b) Frost prevention control
(iii) Reset conditions
Indoor heat exchanger
temperature (°C)
2.5 5 8
0 rps
(c) Cooling overload protective control
(i) Operating conditions
(ii) Detail of operation
Item
SRK20-35ZS-S SRK50ZS-S
Outdoor air temperature
Lower limit speed
Model
1)
2)
1)
2)
1)
2)
(iii) Reset conditions
47°C or more
35 rps
The lower limit of compressor speed is set to 30 or 40 (model SRK50 : 29 or 35) rps.
However, when the thermo OFF, the speed is reduced to 0 rps.
The outdoor fan is stepped up by 3 speed step. [Upper limit 7 (model SRK50 : 8) th speed.]
When the outdoor air temperature (TH2) has become continuously for 30 seconds at 41°C or more, or 47ºC or more
with the compressor running, the lower limit speed of compressor is brought up.
Outdoor air temperature (°C)
40 41 46 47
OFF
ON1
ON2
41°C or more
29 rps
(d) Cooling high pressure control
(i) Purpose
Prevents anomalous high pressure operation during cooling.
(ii) Detector
Outdoor heat exchanger sensor (TH1).
(iii) Detail of operation
P1
P2 P3
Outdoor heat exchanger temperature (°C)
6rps (1)
6rps (1)
0rps
After lapse of 30 sec. or over (3)
After lapse of 30 sec. or over (3)
After lapse of 30 sec. or ove
Notes (1) When the outdoor heat exchanger temperature is in the range of P2-P3
䉝
, the speed is reduced by 6 rps at each 30 seconds.
(2) When the temperature is P3
䉝㻌
or higher, the compressor is stopped.
(3) When the outdoor heat exchanger temperature is in the range of P1-P2
䉝
, if the compressor speed is been maintained and the operation has continued for
more than 30 seconds at the same speed, it returns to the normal cooling operation.
r (3)
lower limit
speed 30 (model SRK50 : 29) rps
(Example) Compressor speed
㻾㼍㼚㼓㼑㻌㻭
㻿㻾㻷㻞㻜㻘㻌㻞㻡
㻿㻾㻷㻟㻡㻘㻌㻡㻜
㻾㼍㼚㼓㼑㻌㻮
㻾㼍㼚㼓㼑㻌㻭
㻾㼍㼚㼓㼑㻌㻮
Range A
31 32
Range B
㻠㻤
㻡㻟
㻡㻝
㻡㻟 㻡㻝
㻡㻤
㻡㻠
㻡㻤 㻡㻟
㻼㻝 㻼㻞
㼀㻴㻝㻔 䉝 㻕
TH1(
䉝
)
㻼㻟
㻢㻟
㻡㻤
㻢㻟
Reduce
speed
(Command speed)
Compressor
speed
The compressor command speed is 0 rps.
Indoor heat exchanger
temperature
Item
5°C or lower 2.5°C or lower
Compressor command speed
Indoor fan
Outdoor fan
4-way valve Depends on compressor speed
Keep the fan speed before
frost prevention control
2.5–5
5–8
Reduced by 4 rps at each 20 seconds
(i) Operating conditions
(ii) Detail of anti-frost operation
1)
2)
'09•SRK-DB-087D
(i) Compressor overheat protection
(i) Purpose:
(ii) Detail of operation
1)
Discharge pipe temperature (˚C)
(Example) Fuzzy
90 100 110
2)
(j) Current safe
Purpose
Detail of operation
(k) Current cut
Purpose
Detail of operation
(l) Outdoor unit failure
(c) Indoor fan motor protection
Cooling Heating
Lower limit speed
Item
Model
(iii)
ࠉ
Reset conditions: When either of the following condition is satisfied.
1)
ࠉ
The outdoor air temperature (TH2) becomes 6ºC ~ 11ºC.
2)
ࠉ
The compressor command speed is 0 rps.
20 rps
24 rps
20 rps
24 rps
item (i), (ii) is satisfied. Once the unit is stopped by this function, it is not
min
-1
100 -110°C
90-100°C
90 -100°C
SRK20 - 35
SRK50
(i)
(ii)
(i)
(ii)
(i)
(ii)
air-conditioning.
has elapsed
air-conditioner