Mitsubishi Heavy Industries SRK25GZ-L1 Handbook page 24

SRK-GZ
S Model SRK502Z-L
1) Starting conditions (Defrosting operation can be started only when all of the following conditions are met.)
After start of heating operation → When it elapsed 60 minutes. (Accumulated operation time)
1
After end of defrosting operation → When it elapsed 60 minutes. (Accumulated compressor operation time)
2
Outdoor unit heat exchanger thermistor (Th5) temperature → When the temperature has been below –2ºC
3
for 3 minutes continuously.
4
When outdoor air temperature thermistor (Th6) – outdoor heat exchanger liquid piping thermistor tempera-
ture (Th5)
A value: Th6
5
During continuous compressor operation
In addition, when the speed command from the indoor controller of the indoor unit during heating operation
has counted 0 rps 10 times or more and all conditions of 1, 2 and 3 above are satisfied (note that when the
temperature for Th5 is 62 rps or more: -2 ˚C or less, less than 62: - 1 ˚C), defrost operation is started.
2) Operation of functional components during defrosting operation
Indoor unit
Indoor fan
Operation lamp
Outdoor unit
Inverter command
frequency
Outdoor fan
4-way valve
3) Ending conditions (Operation returns to the heating cycle when either one of the following is met.)
1
Outdoor heat exchanger thermistor (Th5) temperature: 9˚C higher.
Continued operation time of defrosting → For more than 10 min.
2
(vi) Hot standby (Excepted SRK502 model)
1) Conditions (Hot standby occurs when all of the following conditions are met.)
1
When it lapsed 2 hours continuously after the command frequency turned to 0 Hz during heating operation.
2 When the temperature detected with the external temperature sensor is below –2ºC.
2) Detail
Low voltage is applied to the compressor from the inverter so as to preheat the compressor in which refrigerant
melted in the refrigeration oil is vaporized, circulated smoothly at the start of heating operation and, as a result, the
startup of heating operation is speeded up.
3) Hot standby is reset when the external temperature turns to 0ºC or when the unit has not been operated for more
than 24 hours continuously.
(vii) Heating "HI POWER" operation (HI POWER button on remote controller: ON)
Operation is maintained for 15 minutes with a higher blow out air temperature.
¡
Detail of operation
Item
Inverter command frequency
Indoor fan
Outdoor fan
22
> =
0.44 x outdoor air temperature thermistor (Th6) + A ˚C or more.
> =
< =
-2 ˚C · 4 Th6 -2 ˚C · 6
Hot keep
Corresponding
to speed
OFF
ON
Flashing
(Hot keep)
Fuzzy calculated
value
0
Corresponding
to speed
OFF
ON
OFF
Defrost operation 80 minute
preparation
Defrost operation
(Th5 – 9˚C or 10 minutes)
Defrost control
Model
SRK25GZ-L1 SRK35GZ-L1
112Hz 110Hz
Hot keep M mode
Depends on frequency
Hot keep
80rps
Operation starts 1 to 2
seconds after start of
compressor.
60 seconds Final defrost operation
Normal heating operation restored
Defrost end
Notes (1) When the hot keep fan speed and the fan speed
SRK502Z-L
126rps
(2) Room temperature is not adjusted during the
(3) Protective functions will actuate with prior-
corresponding to the frequency command are
not matched, the fan is operated with the fan
speed whichever lower.
HI POWER operation.
ity even during the HI POWER operation.