94
CDHH-SVX003C-EN
evaporator and condenser headers.
2. Service the auxiliary equipment according to the start-
up and maintenance instructions provided by the
respective equipment manufacturers.
3. Fill and vent the cooling tower, if used, as well as the
condenser and piping. At this point, all air must be
removed from the system (including each pass). Then,
close the vents in the condenser waterboxes.
4. Open all of the valves in the evaporator chilled water
circuit.
5. If the evaporator was previously drained, fill and vent
the evaporator and chilled water circuit. After 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 “Daily Unit Start-up,” p.
93.
Daily Unit Shutdown
Note: 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 shutdown, the
operator may turn Pump Contactors to OFF or open
pump disconnects.
Seasonal Unit Shutdown
Important: 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 “Normal
Operation,” p. 104 (tables for recommended
maintenance of standard and optional features) should
be performed by qualified Trane service technicians.
Note: During extended shutdown 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 Symbio™ 800 controller that is configured to control a
purge system uses the operational sequences described in
this section.
Purge Operating Modes
Purge operating mode options are as follows:
• Stop. The purge condensing unit does not run in this
mode.
• On. The purge condensing unit runs continuously in
this mode, regardless of the chiller’s operational status.
• Auto. The purge condensing unit runs in this mode if
the main compressor of the chiller is operating.
• Adaptive. 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
Start-up and Shutdown
To Next Page
Loading...
