Trane RTWA 70-125 TON - Manual (Page 36)

36 RLC-SVD03A-EN
Compressor Capacity
prevent a compressor from loading even if the chilled water setpoint is not
satisfied. Refer to the RTAA-IOM-4 for discussion on condenser, evaporator,
and current limiting functions and setpoints. Refer to the Mode display under
the Chiller Report on the CLD for an indication of the current running mode.
Checkout Procedure for the Slide Valve and Load/
Unload Solenoids
Make sure unit is off and there is no power in the control panel before
beginning this procedure.
Setup
1. Identify the MCSP Module associated with the compressor to be tested
(1U4 or 1U5). Disconnect the stake-on terminals for the Load and Unload
Solenoid Valves at the MCSP UCM (E7 and E8 respectively) but take care
to identify the wires so as to prevent crosswiring when reconnecting.
ƽ WARNING
Hazardous Voltage w/Capacitors!
Disconnect all electric power, including remote disconnects
before servicing. Follow proper lockout/tagout procedures to
ensure the power cannot be inadvertently energized. For variable
frequency drives or other energy storing components provided by
Trane or others, refer to the appropriate manufacturer’s literature
for allowable waiting periods for discharge of capacitors. Verify
with an appropriate voltmeter that all capacitors have discharged.
Failure to disconnect power and discharge capacitors before
servicing could result in death or serious injury.
Note: For additional information regarding the safe discharge of
capacitors, see PROD-SVB06A-EN or PROD-SVB06A-FR
2. Install a toggle switch between Control Power HOT (1TB3-8 or 9) and the
Load and Unload Solenoid Valve leads (previously connected to E7 and
E8). Initially make sure that the Load toggle switch is open and the
Unload toggle switch is closed.
3. Install a pressure gauge with a refrigerant hose (hose should be long
enough to read the gauge from the control panel) to the slide valve pis-
ton/cylinder cavity Schrader valve located near the load/unload solenoids.
4. Reapply power to the unit and place the chiller in the “Stop” mode. Using
the CLD, select and enable the “Compressor Test” (in the Service Tests
Menu) for the compressor that is to be run. Additionally, to prevent the
opposite refrigeration circuit from running, if desired, the circuit can be
locked out through the CIRCUIT LOCKOUT display in the Service Tests
Menu for the appropriate circuit. Next place the Chiller into the “Auto“
mode and provide all necessary interlocks and a load (or adjust chilled
water setpoint) to start the chiller. The selected compressor will be the
first to stage on (after the restart inhibit timer has expired).