Trane CVHH Installation, Operation And Maintenance Manual page 77

Now that the com pressor m otor is running in the " Delta"
configuration, the inlet guide vanes w ill m odulate,
opening and closing to the chiller load variation by
operation of the stepper vane m otor actuator to satisfy
chilled water setpoint. The chiller continues to run in its
appropriate m ode of operation: Norm al, Softload, Lim it
M ode, and so on (see Figure
rises above the oil cooler setpoint w hile the com pressor is
running, the oil cooler solenoid valve shall be energized to
cool the oil.
If the chilled water tem perature drops below the chilled
water set point by an am ount set as the " differential to
stop" setpoint, a norm al chiller stop sequence is initiated
as follow s:
Figure 43. Sequence of operation: running
Starter
Status is
"Running"
Starting
Chiller Is Running
Compressor
Modulate IGV/AFD
for LWT control
Enforce All Running Mode Diagnostics
Note: If the Oil Tank Temperature rises above the Oil Cooler Control Setpoint whilte the
compressor is running, the Oil Cooler Solenoid Valve shall be energized to cool the unit.
Figure 44. Sequence of operation: satisfied setpoint
Satisfied Setpoint
Running
Preparing Shutdown
Close IGV (0–50 sec)
Command IGV Closed
Enforce All Running Mode Diagnostics
CVHH-SVX001A-EN
43). If the oil tank tem perature
Limit Mode
Chiller Is Running—Limit
Modulate IGV/AFD
for Limit control
Shutting Down
Postlube 3 min
De-Energize
Compressor
Confirm No Compressor Currents
Within 0–30 sec
Hold position of Oil Vent Line Valve
De-Energize Condenser
Water Pump Relay
1. The inlet guide vanes are driven closed (up to
50 seconds).
2. After the inlet guide vanes are closed, the stop relay
and the condenser water pum p relays open to turn off.
The oil and refrigerant pum p m otor w ill continue to run
for 3 m inutes post-lube w hile the com pressor coasts to
a stop. The oil vent line valve w ill then open. The chilled
water pum p w ill continue to run w hile the m ain
processor m odule m onitors leaving chilled water
tem perature preparing for the next com pressor m otor
start based on the " differential to start" setpoint.
Figure 44, p. 77 illustrates this sequence.
Exit
Limit Mode
Chiller Is Running
Modulate IGV/AFD
for LWT control
Shutting Down
De-Energize Oil Pump
Confirm No Oil Pressure*
5 min after oil pump is de-energized
Open Oil Vent Line Valve
*Note: No oil pressure is less than 20.7 kPad (3 psid)
Start-up and Shut-dow n
Chiller
Is
Running
Auto
77