Protective Control Function - Mitsubishi Heavy Industries SRK25ZJ-S Technical Manual
Inverter wall mounted type residential air-conditioners (split system, air to air heat pump type)
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Also See for SRK25ZJ-S:
- Technical manual (273 pages) ,
- Service manual (162 pages) ,
- Data book (60 pages)
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The unit checks the temperature every hour after the start of operation and, if the result of check is not same as the previous
(b)
operation mode, changes the operation mode.
When the unit is started again within one hour after the stop of automatic operation or when the automatic operation is selected
(c)
during heating, cooling or dehumidifying operation, the unit is operated in the previous operation mode.
Setting temperature can be adjusted within the following range. There is the relationship as shown below between the signals
(d)
of the wireless remote controller and the setting temperature.
Cooling
Setting
Dehumidifying
temperature
Heating
(12) Protective control function
Frost prevention control (During cooling or dehumidifying)
(a)
1)
Operating conditions
a)
Indoor heat exchanger temperature (Th2) is lower than 5ºC.
b)
5 minutes after reaching the compressor command speed except 0 rps.
2)
Detail of anti-frost operation
Indoor heat exchanger
Item
Lower limit of compressor command speed
Indoor fan
Outdoor fan
4-way valve
Notes (1) When the indoor heat exchanger temperature is in the range of 2.5~5ºC, the speed is reduced by 4 rps at each 20 seconds.
(2) When the temperature is lower than 2.5ºC, the compressor is stopped.
(3) When the indoor heat exchanger temperature is in the range of 5~8ºC, the compressor command speed is been maintained.
Reset conditions: When either of the following condition is satisfied.
3)
a)
The indoor heat exchanger temperature (Th2) is 8ºC or higher.
b)
The compressor command speed is 0 rps.
(b)
Cooling overload protective control
Operating conditions: When the outdoor air temperature (TH2) has become continuously for 30 seconds at 41ºC or
1)
2)
Detail of operation
a)
The outdoor fan is stepped up by 3 speed step. (Upper limit 7th speed.)
b)
The lower limit of compressor command speed is set to 30 or 40 rps and even if the calculated result becomes lower
than that after fuzzy calculation, the speed is kept to 30 or 40 rps. However, when the thermo becomes OFF, the
speed is reduced to 0 rps.
Reset conditions: When either of the following condition is satisfied.
3)
a)
The outdoor air temperature is lower than 40ºC or 46ºC.
b)
The compressor command speed is 0 rps.
–6
–5
–4
18
19
20
19
20
21
20
21
22
temperature
5°C or lower
22 rps
Depends on operation mode
Depends on command speed
OFF
more, or 47ºC or more with the compressor running, the lower limit speed of compressor is
brought up.
Item
Outdoor air temperature
Lower limit speed
Signals of wireless remote controller (Display)
±0
–3
–2
–1
21
22
23
24
22
23
24
25
23
24
25
26
2.5°C or lower
0 rps
Protects the fan tap just before
frost prevention control
Depends on stop mode
Model
SRK20~35ZJX-S
41°C or more
30 rps
63
-
-
'10 • SRK-T-098
+1
+2
+3
+4
25
26
27
28
26
27
28
29
27
28
29
30
compressor
command
speed
Lower
limit
speed
0 rps
2.5
5
Indoor heat exchanger
temperature (ºC)
47°C or more
40 rps
Unit : ºC
+5
+6
29
30
30
31
31
32
8
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