Operation Control Function By The Outdoor Control; Defrost Operation; Cooling Overload Protective Control - Mitsubishi Heavy Industries FDTC40ZSXVH Service Manual

*It can be set the indoor fan motor off or the heating thermostat OFF with connecting a wired remote control.
In the case, indoor air temperature is detected by sensor on the wired remote control.
(b) Details of control at each operation mode (pattern)
(i) Fuzzy operation
(ii) Hot keep operation
During the heating operation, the indoor fan speed can be controlled based on the temperature of the indoor heat

1.4 Operation control function by the outdoor control

exchanger (Th2) to prevent blowing out of cold air.

(1) Defrost operation

Fan speed
(i)
(ii)
(iii)
(ii) Hot keep operation
(vi)
During the heating operation, the indoor fan speed can be controlled based on the temperature of the indoor heat
exchanger (Th2) to prevent blowing out of cold air.
(1) Defrost operation
0
(i)
(v)
In case satisfied all of following conditions.
• Connect compressor speed 0 rps 10 times or more.
(ii)
• Satisfy 1), 2) and 3) conditions above.
• Outdoor air temperature is 3°C or less.
(iii)
Defrost operation
start
(i)
(vi)
(ii)
-20 -15 -10 -5
(b) Frost prevention control
Outdoor air temperature (℃)
(i) Operating conditions
1)
(v)
2)
In case satisfied all of following conditions.
• Connect compressor speed 0 rps 10 times or more.
(ii) Detail of anti-frost operation
• Satisfy 1), 2) and 3) conditions above.
• Outdoor air temperature is 3°C or less.
(i)
(ii)
(iii) Reset conditions
1)
2)

(2) Cooling overload protective control

(a) Operating conditions
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
Lower limit speed
(b) Detail of operation
(i) The outdoor fan is stepped up by 3 speed step. [Upper limit 8 th speed.]
(ii) The lower limit of compressor speed is set to 30 or 40 rps.
However, when the thermo OFF, the speed is reduced to 0 rps.
(c) Reset conditions
4-way valve
12-42rps
LO
12-30rps
ULO
12-42rps
ECO
Model
SRK20ZSX-S
Auto
HI
MED
LO
ULO
ECO
Models SRK50, 60
0
-5
-10
-15
-20
0 5 10 -20
Indoor heat exchanger
temperature
Item
Lower limit of compressor command speed
Indoor fan
Outdoor fan
4-way valve
Defrost operation
Heating operation
Depends on an operation condition, the time can be longer than 7 minutes.
ON1
OFF
37 38
Outdoor air temperature (°C)
ON ON
12-50rps
12-30rps
12-50rps
SRK25ZSX-S
12-78rps 12-86rps
12-78rps 12-86rps
12-78rps 12-86rps
12-42rps 12-50rps
12-30rps 12-30rps
12-50rps
12-42rps
Defrost operation
start
-15 -10 -5 0
Outdoor air temperature (℃)
5°C or lower
(models SRK50, 60 : 25 rps)
Keep the fan speed before
frost prevention control
Depends on compressor speed
2.5–5
5–8
Max. 18 minutes.
ON3
ON2
40 41 46 47
26
- -
(3 minutes ON)
12-66rps
12-30rps
12-66rps
SRK35ZSX-S SRK50ZSX-S
12-98rps
12-98rps
12-98rps
12-66rps
12-30rps
12-66rps
5 10
compressor
speed
Lower
limit
2.5°C or lower
speed
0 rps
2-7 minutes
Hot keep operation
ON1
OFF
40 41
Outdoor air temperature (°C)
12-78rps 12-90rps
12-38rps 12-38rps
12-78rps 12-90rps
'18 • PAC-SM-297
SRK60ZSX-S
12-106rps 12-120rps
12-106rps 12-120rps
12-106rps 12-120rps
12-78rps 12-90rps
12-38rps 12-38rps
12-78rps 12-90rps
'09•SRK-DB-087D
2.5 5 8
Indoor heat exchanger
temperature (°C)
ON2
46 47