Midea MGB-D65W/RN1

Air-cooled modular chiller unit 50Hz MCAC-ATSM-2011-12
106
11.2 Troubles and Solutions
Troubles Possible reasons Solutions
Over high air
discharge pressure
(Cooling operation)
Air or other non-condensing gas still
in the system
Discharge gas from refrigerant charging inlet.
Re-vacuum the system if necessary.
Fins in the condenser are dirty or foreign
substance blocking fins
Clean condenser fins
Insufficient chilling air volume or condenser
fan error
Check and repair the condenser fan, recover the
normal operation
Excessive high air suction pressure See “Excessive high air suction pressure”
Excessive refrigerant charging volume Discharge the excessive refrigerant
Over high ambient temperature Check ambient temperature
Over low air
discharge pressure
(Cooling operation)
Surrounding Temp. is lower Measure the surrounding Temp
Refrigerant leak or insufficient Leak-hunting or recharging
Low suction pressure Refer to the “low suction pressure”
Over high air
suction pressure
(Cooling operation)
Refrigerant over-charged Discharge the additional refrigerant
High Temp. of the inlet chilled-water Check the heat insulation of water pipeline
Over low air
suction pressure
(Cooling operation)
Insufficient water flow
Measure the Temp difference between inlet and outlet
water, adjust the water flow
Low Temp. of inlet chilled-water Check installation
Refrigerant leak or insufficient Leak-hunting or recharging
Scaling in the evaporator Descaling
Over high air
discharge pressure
(Heating operation)
Insufficient water flow
Check temperature difference at water inlet and outlet,
and adjust the water flow volume
Air or other non-condensing gas still in the
system
Discharge gas from refrigerant charging inlet.
Re-vacuum the system if necessary
Scaling in water side of heat exchanger Descaling
Over high temperature in chilling water inlet Check water temperature
Excessive high air suction pressure See “Excessive high air suction pressure”
Over low air
discharge pressure
(Heating operation)
Over low temperature of chilling water Check chilling water temperature
Refrigerant leakage or insufficient
refrigerant volume
Test leakage or charge sufficient refrigerant to the
system
Excessive low air suction pressure See “Excessive low air suction pressure”
Over high air
suction pressure
(Heating operation)
Over heat air in the side of air heat exchanger Check ambient temperature around it
Excessive refrigerant charging volume Discharge the excessive refrigerant
Over low air
suction pressure
(Heating operation)
Insufficient refrigerant charging volume Charge sufficient refrigerant to the system
Insufficient air flow volume Check fan rotating direction
Air loop short-circuit Reason about remove air short-circuit
Insufficient frost-removal operation
Error comes out from 4-way valve or thermal resistor.
Replace a new one if necessary
Compressor stops
because of
freeze-proof
protection
(Cooling operation)
Insufficient chilling water flow volume
Error comes from pump or flow-type water volume
control. Check and
repair or replace a new one.
Gas still in water loop Discharge air
Thermal resistor error
Upon error have been confirmed, please replace a
new one
Compressor stops
because
of Hi-pressure
protection
Over high air expelling pressure See “Over high air expelling pressure”
Hi-pressure switch error
Upon error have been confirmed, please replace a
new one
Compressor stops
because of motor
Overload.
Over high air expelling pressure and air
suction pressure
See “Over high air expelling pressure” and “Over high
air suction pressure”
Hi-voltage or Lo-voltage, signal phase or
phase unbalance
Confirm voltage not higher or lower than the rated
voltage 20V
Short circuit comes out from motor or
connecting interface
Confirm resistors at motor are connected
corresponding to terminals
Overload assembly error Replace a new one