Current Safe; Current Cut; Outdoor Unit Failure; Rotor Lock - Mitsubishi Heavy Industries FDT Series Technical Manual

(4) Lower limit speed
Model
Lower Limit Speed
2) If the temperature of 115ºC is detected by the sensor on the discharge pipe, then the compressor will stop immediately.
When the discharge pipe temperature drops and the time delay of 3 minutes is over, the unit starts again within 1
hour but there is no start at the third time.
(9)

Current safe

(a) Purpose: Current is controlled not to exceed the upper limit of the setting operation current.
(b) Detail of operation:

(10) Current cut

(a) Purpose: Inverter is protected from overcurrent.
(b) Detail of operation: Output current from the inverter is monitored with a shunt resistor and, if the current exceeds the

(11) Outdoor unit failure

This is a function for determining when there is trouble with the outdoor unit during air conditioning.
restarted.
(a) When the input current is measured at 1 A or less for 3 continuous minutes or more.
(b) 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.
(12) Serial signal transmission error protection
(a) Purpose: Prevents malfunction resulting from error on the indoor
(b) Detail of operation: If the compressor is operating and a serial signal cannot be received from the indoor control with

(13) 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.
(14) Outdoor fan motor protection
If the outdoor fan motor has operated at 75 rpm or under for more than 30 seconds, the compressor and fan motor are stopped.
(15) Outdoor fan control at low outdoor temperature
(a) Cooling
Operating conditions: When the outdoor air temperature (TH2) is 22ºC or lower continues for 30 seconds while the
1)
Detail of operation: After the outdoor fan operates at A speed for 60 seconds; the corresponding outdoor heat exchanger
2)
Item
Cooling Heating
25 rps 32 rps
board of the outdoor unit and, if the operation current value reaches the limiting current value, the
compressor command speed is reduced.
If the mechanism is actuated when the compressor command speed is less than 30 rps, the compres-
sor is stopped immediately. Operation starts again after a delay time of 3 minutes.
setting value, the compressor is stopped immediately. Operation starts again after a delay time of
3 minutes.
outdoor control having serial signals continues for 7 minute 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.
compressor command speed is other than 0 rps.
temperature shall implement the following controls.
Value of A
Outdoor temperature > 10˚C
Outdoor temperature < = 10˚C
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outdoor signals.
Outdoor fan
2nd speed
1st speed
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