Trane SCXG-SVX01B-EN manual Installation startup, Unit Startup Procedures, Compressor Damage

Installation startup

Unit Startup Procedures

￿WARNING

Hazardous Voltage w/Capaci- tors!

Disconnect all electric power, including remote disconnects before servicing. Follow proper lockout/tagout proce- dures to ensure the power cannot be inadvertently energized. For variable frequency drives or other energy storing components provided byTrane 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 regard- ing the safe discharge of capacitors, see PROD-SVB06A-EN or PROD-SVB06A-FR.

Pre-Startup Checklist

1.Verify electrical connections are tight.

2.Water-cooled: Access the liquid line service valves.Verify the liquid line service valve is open at startup.

Note: Each compressor suction line contains a low pressure sensor that will shut the compressor down in low pressure situations. See Table O-SO-2.

3.Ensure system components are properly set and installed.

4.Inspect all ductwork and connections.

5.Remove compressor and fan assembly tie down bolts. On 20 - 38 ton units, do not remove the fan assembly shipping blocks.Tie down bolts if the fan speed is 750 rpm or less.

6.Ensure fan rotation is in the direction of the arrow on the fan housing. If it is incorrect, verify the incoming power phasing is correct. Switch wires on the fan contact to properly phase fan if necessary.

7.Check the fan belt condition and tension. Adjust the tension if belts are floppy or squeal continually. Replace worn or

fraying belts in matched sets.

Startup

￿WARNING

Live Electrical Components!

During installation, testing, servicing and troubleshooting of this product, it may be necessary to work with live electrical components. Have a qualified licensed electrician or other individual who has been properly trained in handling live electrical components perform these tasks. Failure to follow all electrical safety precautions when exposed to live electrical components could result in death or serious injury.

NOTICE

Compressor Damage!

Never manually or automatically pump down system below 7 psig.This will cause the compressor to operate in a vacuum and result in compressor damage.

To start the unit, complete the following steps in order.

1.Apply power to the unit. Close the unit disconnect switch option.

2.Make sure the liquid line service valves are open on water cooled units.

3.Adjust setpoints at the HI.

Note: A sufficient cooling load must be visible to refrigerant circuit controls for mechanical refrigeration to operate. If necessary, temporarily reduce the dis- charge air setpoint to verify the refrigeration cycle operation.

4.Check voltage at all compressor terminals to ensure it is within 10% of nameplate voltage.

5.Check voltage imbalance from these three voltage readings at each compressor. Maximum allowable voltage imbalance, phase to phase is 2%.

6.Check amp draw at compressor terminals. RLA and LRA is on the unit nameplate.

7.Measure amp draw at evaporator fan motor terminals. FLA data is on the motor nameplate.

8.After the system has stabilized (15 to 30 minutes), check and record operating pressures and temperatures for all circuits.

Using the startup log on the following pages, establish nominal conditions for consistent measurements as follows:

•Leaving air greater than 60°F

•Entering air temperature = 70 to 90°F

•Entering water temperature > 60°F

•Inlet guide vanes at least halfway open

With all compressors running at full load:

1.Compute superheat from the suction line pressure and temperature at the compressor on each circuit. Adjust the thermal expansion valve settings if necessary. Superheat should be between 12 and 17°F.

2.Inspect refrigerant flow in the liquid line sight glass. Flow should be smooth and even, with no bubbles once the system has stabilized.

Normal startup will occur provided that Tracer Summit is not controlling the module outputs or the generic BAS is not keeping the unit off.To preventTracer Summit from affecting unit operation, removeTracer wiring and make required changes to setpoint and sensor sources.

Operating & Programming Instructions Reference the IntelliPak Self-Contained Programming Guide, PKG-SVP01B-EN,for available unit operating setpoints and instructions. A copy ships with each unit. For units with the VFD option, reference the installer guide that ships with each VFD.

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