'20 • SRF-SM-311
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16
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(k) Current cut
(i) Purpose
Inverter is protected from overcurrent.
(ii) Detail of operation
Output current from the inverter is monitored with a shunt resistor and, if the current exceeds the setting value, the com-
pressor is stopped immediately. Operation starts again after a delay time of 3 minutes.
( l ) Outdoor unit failure
This is a function for determining when there is trouble with the outdoor unit during air-conditioning.
The compressor is stopped if any one of the following in item (i), (ii) is satisfied. Once the unit is stopped by this function, it is
not restarted.
(i) When the input current is measured at 1 A or less for 3 continuous minutes or more
(ii) If the outdoor unit sends a 0 rps signal to the indoor unit 3 times or more within 20 minutes of the power being turned on.
(m) Indoor fan motor protection
When the air-conditioner is operating and the indoor fan motor is turned ON, if the indoor fan motor has operated at 300 min
-1
or under for more than 30 seconds, the unit enters first in the stop mode and then stops the entire system.
(n) Serial signal transmission error protection
(i) Purpose
Prevents malfunction resulting from error on the indoor
↔
outdoor signals.
(ii) Detail of operation
If the compressor is operating and a serial signal cannot be received from the indoor control with outdoor control having
serial signals continues for 7 minutes and 35 seconds, the compressor is stopped.After the compressor has been stopped, it
will be restarted after the compressor start delay if a serial signal can be received again from the indoor control.
(o) Rotor lock
If the motor for the compressor does not turn after it has been started, it is determined that a compressor lock has occurred and
the compressor is stopped.
(p) Outdoor fan motor protection
If the outdoor fan motor has operated at 75 min
-1
or under for more than 30 seconds, the compressor and fan motor are stopped.
(q) Outdoor fan control at low outdoor air temperature
(i) Cooling
1) Operating conditions
When the outdoor air temperature (TH2) is 22ºC or lower continues for 30 seconds while the compressor command
speed is other than 0 rps
2) Detail of operation
After the outdoor fan operates at A speed for 60 seconds; the corresponding outdoor heat exchanger temperature shall
implement the following controls.
a) Outdoor heat exchanger temperature =< 21ºC
After the outdoor fan speed drops (down) to 1 speed for 60 seconds; if the outdoor heat exchanger temperature
is lower than 21ºC, gradually reduce the outdoor fan speed by 1 speed. (Lower limit 1st speed)
b) 21ºC < Outdoor heat exchanger temperature =< 38ºC
After the outdoor fan speed maintains at A speed for 20 seconds; if the outdoor heat exchanger temperature is
21ºC-38ºC, maintain outdoor fan speed.
c) Outdoor heat exchanger temperature > 38ºC
After the outdoor fan speed rises (up) to 1 speed for 60 seconds; if the outdoor heat exchanger temperature is
higher than 38ºC, gradually increase outdoor fan speed by 1 speed. (Upper limit 3rd speed)
Outdoor temperature > 10˚C
Outdoor temperature <= 10˚C
2nd speed
Outdoor fan
1st speed
¡
Value of A
