General Control Scheme Flowchart - Midea VRF Series Service Manual

V6R VRF 50/60Hz

1 General Control Scheme Flowchart

Sections 3-2 to 3-8 on the following pages detail when each of the controls in the flowchart below is activated.
Stop operation
 Abnormal shutdown
 System stops
 A unit stops when the load demanded decreases
Standby control
 Crankcase heater control
Startup control
 Compressor startup delay control
 Startup control for cooling only/main cooling
operation
 Startup control for heating only/main heating
operation
Normal operation control
 Component control during normal operation
 Compressor control
 Heat exchanger control
 Electronic expansion valve control
 Outdoor fan control
Protection control
 High pressure protection control
 Low pressure protection control
 Discharge temperature protection control
 Over-current protection control
 Ambient temperature out of range protection
control
 Inverter module temperature protection control
 Wet compression protection control
 High pressure ratio protection control
26
Thermo on
Legend
Numbers in the top right-hand corners
of boxes indicate the relevant section
of text on the following pages.
2
3
Special control
4
Thermo on
5
Conditions met
for oil return
Conditions met
for defrosting
6
 Outdoor unit duty cycling
 Oil return operation
 Defrosting operation
Other control
 Overload control
 Pump-down control
 Snow-blowing control
 Auto mode and Dual set
points
 Low noise mode
 Power limitation mode
7
8