Installation and Maintenance Manual

Unit Shutdown
180 RLC-SVX09H-EN
Seasonal Unit Shutdown
1. Perform normal unit stop sequence using <Stop> key.
Note: Do not open starter disconnect switch. It must
remain closed to provide power from control
power transformer to the oil heaters.
2. Verify chilled water and condenser water pumps are
off. If desired, open disconnect switches to pumps.
3. Drain condenser piping and cooling tower, if desired.
4. Remove drain and vent plugs from condenser headers
to drain the condenser.
5. Verify that the oil heaters are working.
6. Once unit is secured, perform maintenance identified
in the following sections.
Figure 82. RTUD Normal shutdown
RTUD Sequence of Operation: Normal Commanded Shutdown to Stopped or Run Inhibit
Running
Local Stop
Chiller Level Diagnostic – Normal Shutdown Latched
Chiller Level Diagnostic – Normal Shutdown Nonlatched
Tracer Stop
External Auto-Stop
Stopped
or
Run Inhibit
Shutting Down
Energize Unload
Solenoid Both
Compressors
Shutting Down
Circuit Submodes:
Operational Pumpdown
De-Energize both
Compressors and Energize Oil Heaters
Brief Run-Unload, both
Compressors (5 Seconds)
Leave Both Cprsr’s Unload Solenoids
Energized for 60 mins
Time out Evap
Pump Off Delay
(adj 0-30 minutes)
De-Energize Evaporator Water Pump Relay
1 sec
De-Energize Oil Return
Fill and Drain Solenoids
of Both Circuits
DeEnergize Step Load Solenoid Both
Compressors
Turn off both Circuits’
Condenser Fans
Leave EXVs Closed or Close EXV for Circuits’ Off Cycle
Close EXV’s and Perform Operational Pumpdown (if
regd*) for both Circuits
Shutting Down
Circuit Submodes:
AUTO
Check for Normal
Pumpdown Termination
Criteria Met**
Normal Pumpdown Termination
Criteria Met for both Circuits
Confirm No
Compressor Currents
Stopped
Circuit Submodes:
AUTO
*Operational Pumpdown is required if the Outdoor Air Temperature
is less than 50F, or if it is less than the Entering Evaporator Water
Temperature plus 5F. **Operational pumpdown is terminated normally when:
The Evaporator liquid level for the circuit is -36 mm or lower
and
The Evaporator saturation temperature for the circuit is below either 32 F or
LRTC set point + 4F, whichever is lower
.
The maxim
um allowed time for Operational Pumpdown is 2 minutes.
Operational Pumpdown 2 minutes max