Mitsubishi Heavy Industries FDTCVA SERIES Technical Manual page 181

(iii) Current safe control
1) If the inverter primary current (CT current) becomes higher than the
following set value, the compressor speed is reduced. If the current
is still above the set value after the speed is reduced, the speed is
reduced again.
2) If the current value drops to the cancellation value continuously for 3 minutes, this control is ended and the speed
protection cancel operation is started.
(iv) High pressure control
1) Compressor speed control during heating
If the indoor heat exchanger temperature (ThI-R1, 2, whichever higher) exceeds the set value and if the compressor
speed is faster than the set value mentioned in the following table, compressor speed is reduced to drop the high
pressure.
Item
Compressor rotational speed (rps)
Indoor heat exchanger temp (˚C)
2) Compressor speed control during cooling
If the outdoor heat exchanger temperature (Tho-R1, R2, whichever higher) exceeds the set value and if the compres-
sor speed is faster than the set value mentioned in the following table, compressor speed is reduced to drop the high
pressure.
Item
Compressor rotational speed (rps)
Outdoor heat exchanger temp (˚C)
3) Operation stop control according to indoor heat exchanger temperature
If an indoor heat exchanger temperature (detected by ThI-R1, R2) of 65°C or higher is detected continuously for 2
seconds during compressor operation in the heating mode, the compressor's speed is controlled. If the indoor heat
exchanger's temperature drops to 47°C or lower, this control ends.
4) Control according to the outdoor heat exchanger temperature
a) If an outdoor heat exchanger temperature (detected by Tho-R1, R2) that is higher than the set value is detected,
during compressor operation in the cooling mode, the compressor is stopped. When the temperature drops to
or below the set value, compressor operation resumes automatically.
b) If the outdoor heat exchanger temperature exceeds the set value 5 times within a period of 60 minutes or con-
tinuously for 60 minutes even when the compressor is stopped, an anomalous stop, (E35) occurs.
Note (1) If an outdoor heat exchanger temperature anomalous stop occurs and the temperature does not drop to 51ºC or lower for 3 minutes
continuously, operation cannot be resumed.
5) Anomalous detected by the high pressure switch (63H1)
If the pressure rises and the high pressure switch (4.15 open/3.15 closed MPa) operates (opens) 5 times within 60
minutes or operates (remains open) continuously for 60 minutes even when the compressor is stopped, an anomalous
stop (E40) occurs.
(v) Low pressure control [LPT]
1) Compressor speed protective control
a) If all the following conditions are satisfi ed 5 minutes or more after the compressor starts or after a defrost reset,
the compressor speed is lowered.
If the low pressure is 0.15 MPa or lower continuously for 10 seconds.
If the compressor speed is 20 rps or higher (for model 302), 40 rps or higher (for models 402 ~ 602) or 30
rps or higher (for models 802, 1002).
b) The low pressure is detected again 30 seconds later, and if it is lower than 0.15 MPa, the compressor speed is
lowered again.
c) If the low pressure becomes 0.189 MPa or higher, this control ends.
Model
302
20
52 ~ 58
Model
302
20
52 ~ 58
Compressor operation
51
Outdoor heat exchanger temperature (˚C)
180
- -
Model
302
402, 502, 602
802
1002
402 ~ 602
40
52 ~ 58
402 ~ 602
40
52 ~ 58
Compressor stops
65
Set value (A)
15
23
17
20
802, 1002
30
52 ~ 58
802, 1002
30
54 ~ 60