Unit Start-Up And Shut-Down Procedures; Sequence Of Operation; Unit Startup - Trane RTXC-XE Series Installation, Operation And Maintenance Manual

Unit Start-up and Shut-down Procedures

Sequence of Operation

Unit Startup

RTXC-SVX003D-EN
Important: Initial unit commissioning start-up must be performed by Trane, or an agent of Trane
specifically authorized to perform start-up and warranty of Trane products. Contractor
shall provide Trane (or an agent of Trane specifically authorized to perform start-up)
with notice of the scheduled start-up at least two weeks prior to scheduled start-up.
This section will provide basic information on unit operation for common events. With
microelectronic controls, ladder diagrams cannot show today's complex logic, as the control
functions are much more involved than older pneumatic or solid-state controls.
Adaptive control algorithms can also complicate the exact sequence of operations. This section
illustrates common control sequences.
If the pre-start checkout, has been completed, the unit is ready to start.
1. Ensure the "STOP" key display on the TD7. As necessary, adjust the setpoint values on the
TD7 menus using TU and record in.
Any change of the protection setpoints might result the loss of related guaranteed rights
without the authorization or approval from Trane Company.
2. Close the fused-disconnect switch for the chilled water pump.
3. Check the service valves on the oil line and liquid line for each circuit. These valves must be
open before starting the compressors except the service of receiver.
Compressor Damage!
Catastrophic damage to the compressor will occur if the oil line shut off valve or the isolation
valves are left closed on unit start-up.
4. Power on the electrical heater of evaporator.
5. Ensure that the Uninterruptible Power Supply to the heaters of compressor oil sump and oil
separator has been operating properly for a minimum of 12 hours before starting. Failure to
do so may result in compressor damage.
6. Select the MODE and press the AUTO key on TD7. If the unit control calls for operation and all
safety interlocks are closed, the unit will start. The compressor(s) will load and unload in
response to the leaving chilled water temperature.
7. Once the system has been operating for approximately 30 minutes and has become
stabilized, complete the remaining start-up procedures, as follows:
1) Check the discharge pressure, suction pressure under Refrigerant Report on the TD7
display after compressor full loaded. The pressures are referenced to sea level (standard
atmospheric pressure is 101.35kPa/14.6960 psia). The approach temperature should be
within the range of
2) Check both suction and discharge superheat of the compressor. The discharge superheat
should be always above 10°C, while the suction superheat normally in the range of 2°C ~
6°C at heating mode.
3) Measure the system subcooling. Bubbles in the EXV sight glasses indicate either low
refrigerant charge or excessive pressure drop in the liquid line or a stuck open expansion
valve. A clear sight glass alone does not mean that the system is properly charged. Also
check system subcooling, liquid level control and unit operating pressures.
NOTICE
CAUTION
Table 7. Unit Operation Status.
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