General Control Scheme Flowchart - Trane 4TVH0086FE000AA Service Manual

1 General Control Scheme Flowchart

Sections 3-2 to 3-7 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 operation
 Startup control for heating operation
Normal operation control
 Component control during normal operation
 Compressor output control
 Compressor step control
 Operation priority and rotation of compressors
 Electronic expansion valve control
 Outdoor fan control
Protection control
 High pressure protection control
 Low pressure protection control
 Discharge temperature protection control
 Compressor and inverter module protection
control
 Disable heating control
Thermo on
2
3
4
Thermo on
5
Conditions met
for oil return
Conditions met
for defrosting
6
Legend
40
Special control
 Oil return operation
 Defrosting operation
Numbers in the top right-hand
corners of boxes indicate the
relevant section of text on the
following pages.
7