CyberChiller Series Installation, Operation & Maintenance Manual

3.0START-UP/COMMISSIONING

3.1Operation

For new installations, ensure the unit is ready to operate by going through the Checklist for Completed Installation, located in Appendix A, prior to start-up.

NOTE

A Warranty Registration and Start-Up Checklist is provided with the unit data package. It should be completed during start-up and sent to SATS. This checklist should be used as a guideline for items that need to be confirmed during start-up.

Start-up must be performed by a journeyman, refrigeration mechanic or an air conditioning technician.

3.2Step by Step Start-Up Instructions

1.Replace all equipment removed prior to performing start-up checks.

2.Apply power to start the CyberChiller system at the main power disconnect switch.

NOTE

The compressor(s) may have a time delay on start-up.

Both refrigeration circuits must be tested at start-up. There are several ways to force the second circuit into operation. Refer to the separate controller operation instructions sent with your unit in the data pack- age.

3.Test cooling operation by adjusting the leaving fluid temperature setpoint. The compressor should come on and the chilled water supply should gradually drop in temperature.

3.2.1Operational Description

3.2.1.2Compressor

1.Compressor starts.

2.The compressor takes low pressure, low tempera- ture gas and compresses it to a high temperature, high pressure gas.

3.The refrigerant then flows to the condenser coil. The high temperature, high-pressure gas from the compressor is cooled by the flow of water/glycol/ air through the condenser coil and is changed into a low temperature, high-pressure liquid.

4.The low temperature, high-pressure liquid refriger- ant then flows to the receiver. The receiver acts as a storage tank for the liquid refrigerant that is not in circulation.

5.The refrigerant drier/strainer removes any moisture (water vapor) or impurities that may be carried by the liquid refrigerant.

6.The refrigerant then flows through the liquid sight glass. This device indicates the presence of moisture and state of refrigerant in the system.

7.The liquid line solenoid valve controls the flow of refrigerant before going to expansion valve, which controls the amount of liquid refrigerant to the heat exchanger. The expansion valve senses the temperature and pressure of the refrigerant as it leaves the heat exchanger. By use of a sensing bulb and an external equalizer line the valve constantly adjusts the flow of liquid refrigerant to the heat exchanger.

8.As the liquid refrigerant leaves the expansion valve it enters the heat exchanger. The evaporation of the liquid refrigerant within the heat exchanger removes heat from the water coolant.

9.The refrigerant gas is then drawn back to the compressor and the cycle is repeated.

10.Hot gas from the compressor discharge line is injected into the inlet of the heat exchanger by the hot gas bypass regulator valves. The system controller signals the hot gas regulator valves to proportionally vary the rate of hot gas being injected into the inlet of the heat exchanger as a function of the supply coolant temperature sensed. The hot gas will mix with the refrigerant from the expansion valve. The expansion valve will meter the flow of liquid refrigerant as needed to maintain super heat to approximately 9° - 11°F.

11.The hot gas valve(s) act together with the expan- sion valve(s) to control the temperature of the supply coolant.

3.2.1.3Coolant System

The water coolant system is a closed loop re-circulating system. The pressurized supply coolant flows through the electronics equipment removing heat and then is returned to the expansion tank inside the CyberChiller. The fluid is pumped from the expansion tank through the system heat exchanger where heat is removed from the fluid. After cooling, the fluid is re-

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(©October, 2006)