Daily Unit Shut-Down; Seasonal Unit Shut-Down; Earthwise Purge; Sequence Of Operations - Trane CVHH CenTraVac Installation, Operation And Maintenance Manual

S S t t a a r r t t - - u u p p a a n n d d S S h h u u t t - - d d o o w w n n
all air is removed from the system (including each
pass), close the vent valves in the evaporator
waterboxes.
6. Lubricate the external vane control linkage as
needed.
7. Check the adjustment and operation of each safety
and operating control.
8. Close all disconnect switches.
9. Perform instructions listed in
up," p. 95.

Daily Unit Shut-down

N N o o t t e e : : Also refer to the figure (satisfied setpoint) in
"Start-up Sequence of Operation—Wye-delta," p.
87.
1. Press STOP.
2. After compressor and water pumps shut down, the
operator may turn Pump Contactors to OFF or open
pump disconnects.

Seasonal Unit Shut-down

I I m m p p o o r r t t a a n n t t : : Control power disconnect switch must
remain closed to allow oil sump heater
operation. Failure to do this will allow
refrigerant to condense in the oil pump.
1. Open all disconnect switches except the control
power disconnect switch.
2. Drain the condenser piping and cooling tower, if
used. Rinse with clean water.
3. Remove the drain and vent plugs from the
condenser headers to drain the condenser. Air-dry
bundle of residual water.
4. Once the unit is secured for the season, the
maintenance procedures described in
Operation," p. 106 (tables for recommended
maintenance of standard and optional features)
should be performed by qualified Trane service
technicians.
N N o o t t e e : : During extended shut-down periods, be sure to
operate the purge unit for a two-hour period
every two weeks. This will prevent the
accumulation of air and non-condensables in the
machine. To start the purge, change the purge
mode to ON in the unit control "Settings Purge"
menu. Remember to turn the purge mode to
"Adaptive" after the two-hour run time.

EarthWise Purge

Sequence of Operations

A Tracer® UC800 controller that is configured to
control a purge system uses the operational sequences
described in this section.
96
"Daily Unit Start-
"Normal
Purge Operating Modes
Purge operating mode options are as follows:
• S S t t o o p p . . The purge condensing unit does not run in
this mode.
• O O n n . . The purge condensing unit runs continuously
in this mode, regardless of the chiller's operational
status.
• A A u u t t o o . . The purge condensing unit runs in this mode
if the main compressor of the chiller is operating.
• A A d d a a p p t t i i v v e e . . The purge condensing unit operation
depends on past purge activity.
Adaptive Mode
The objectives of operating the unit in the Adaptive
mode are to:
• Enable purge system operation.
• Enable the refrigeration circuit to effectively
accumulate non-condensables whether or not the
chiller is running.
• Provide information to an operator regarding
whether leakage is on the high-pressure or low-
pressure side of the chiller.
• Decrease energy usage by running the purge
refrigeration circuit only when needed to remove
non-condensables, rather than running it
continuously.
The Adaptive mode requires historical operating data
so that the controller can make optimal decisions
regarding how to run the purge refrigeration circuit in
the future. On initial start-up of a chiller that is in
Adaptive mode, the purge refrigeration circuit runs
continuously for 168 hours (7 days). The chiller
compressor may or may not be running during this
period.
Following the initial data collection period, the
Adaptive mode customizes the purge refrigeration
circuit operation during two distinct chiller operating
conditions:
• Chiller compressor On
• Chiller compressor Off
Adaptive Mode Process—Chiller Compressor On
The following figure illustrates the process described in
this subsection.
When the chiller compressor starts, the purge
refrigeration circuit starts. The purge refrigeration
circuit continues to run until 60 consecutive minutes of
running occur without any pump-out of non-
condensables. The Pumpout Time is the greater of the
following two values that the controller has been
tracking:
• The pump-out time with the chiller On, over the last
24 hours
CVHH-SVX001G-EN