Mitsubishi Heavy Industries SRK25GZ-L1 Handbook page 1044

FDC-HKXR
(19) Devices related to unit protection and maintenance
(a) Test Run Mode
The test run mode can be set from the outside by using the switch SW3-4,5 on the outdoor unit control circuit board
(i) Switch function
Switch
ON
SW3-4
OFF
ON
SW3-5
OFF
(ii) The maximum frequency of outdoor unit in test run operation (At the time of rated capacity)
Model
Maximum operation frequency (Hz)
Remarks : Fuzzy control is not performed in test run operation.
(Operation is executed.) Other controls are effective.
(b) Expansion Valve Control for oil Return
After the compressor operated for 10 hours, and when the compressor is turned, stop the compressor to collect refrigerant
oil, turn off the thermostat, and fully open indoor unit expansion valves of FAN and adnormally stopped units one by one.
(Open expansion valves in the sequence that addresses were registered to outdoor units and not of the address number.
(c) High Pressure Control in Heating Operation
When (63H2) [2.84 close/2.26 open MPa (29.0 close/23.0 open kgf/cm
Hz, and outdoor unit fan stops preventing pressure increase. Frequency control is canceled after 6 minutes from reset of
63H2, then the compressor returns to the normal operation.
Note (1) Detail of Frequency Control Canceling Operation
When a high pressure control is canceled, the frequency increases 5 Hz, and the frequency is retained for 3 minutes. The
frequency increases 5 Hz every 3 minutes to the normal operation.
(d) Discharge gas Temperature Control (All Operation Modes)
When the discharge gas temperature (discharge gas thermistor : Th
with Th ) is controlled by opening and closing the liquid bypass solenoid valve (SV1) and by lowering the frequency.
O-D
Note (1) Th > 115°C .......SV
O-D
The expansion valve of operating indoor unit open 5% approx.
Th > 120°C .......The frequency is lowered 10Hz each time at intervals of 2 minutes (Lower Limit: 35 Hz of the
O-D
full load or a hot gas bypass.) (Th
Th > 130°C.......abnormal stop
O-D
[The operation can be resumed at a temperature bellow 90°C]
(e) Compressor Control at the during of startup
(i) Inrush Current the compressor with 5Hz to the starting.
Also, at the time of startup, fully open the expansion valve of the indoor unit in the operator cab for 4 minutes.
(ii) Protective Start of Compressor
When the inverter starts, the compressor start under protection.
Operate with hot gas bypass up to 35 Hz after the start, operate with full loads of 60 Hz for 15 seconds, then operate
with the decision frequency. When the frequency is higher than 65 Hz, they operate with 65 Hz for one minute 45
seconds after the start. But when the compressor starts first time after the power is turned on, and when the compressor
starts after stop for more than 6 hours, it increases the frequency 5 Hz each minute for 13 minutes.
1042
• To operate all connected indoor units.
• Indoor units demands the maximum frequency and outdoor units are operated with the maximum frequency
according to request from the indoor unit.
• Normal operation
• When SW3-4 is set to ON: Cooling operation
• When SW3-4 is set to ON: Heating operation
-Open [Th < 108°C Closes]
1 O-D
= < 115°C are canceled)
O-D
Function
FDCP2001,2501 type
95
2
)] operates, the compressor revolution decrease 10
D) increases above the set point, the temperature (detected
O-