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Chiller Connections, Finalizing and Testing


Installing Chiller Systems: Chapter 3


Chiller Connections


By the end of this module, you should be able to: Describe the water-side connection of a chiller,

Describe how to install Victaulic coupling, and

Describe the electrical connections of a chiller. Skip to quiz!


Water-Side Connections


The chiller involves a series of connections for the evaporator, condenser, and electrical connections. The chiller connections are made by a certified and experienced technician using schematic drawings. We will discuss the water-side connections, which are the basic in all types of chillers.


The standard connections are:

  • Flexible connector (Bellows),

  • Flow switch,

  • Strainer,

  • Balancing valve,

  • Temperature sensor,

  • Pressure gauge,

  • Drain valve,

  • Gate valve, and

  • Vent plug.


Flexible connector: It is made up of neoprene rubber, and it’s the first connection made to any chiller, and it is also known as bellows. The main purpose is to prevent the vibrations from distributing from the chiller to the pipeline. Pipe joints may get cracked, or even connections might fail if the flexible connector is not used.


Flexible connectors are available in various sizes depending on the pipe connecting to a chiller. Flexible connectors are used to:

  • Isolate the transfer of noise,

  • Isolate the transfer of vibrations,

  • Compensate for any misalignment, and

  • Reduce stress on the pipe network.


A flow switch is included in chilled water systems to ensure the proper amount of water flow to the evaporator before the unit starts or shuts down. A factory-included thermal dispersion flow switch will be installed on packaged models.


A flow switch may be separately field-provided or optionally shipped loose for field installation on remote evaporator models. Installation should be done as per the manufacturer’s instructions included with the switch. Flow switches should be calibrated to shut off the unit when operated below the minimum flow rate for the unit.


The extension pipe is located adjacent to the evaporator with the strainer then mounted to it. The strainer must be mounted per manufacturer’s instruction with the arrows in the flow direction; inlet and outlet are noted with the help of arrows.


Use one grooved clamp to mount the extension pipe to the evaporator and the second to mount the strainer to the pipe. The clamps to mount the field piping to the strainer are field supplied. The piping and strainer must be supported to prevent any stress on the evaporator nozzle.


The balancing valve or double regulating valve controls the water flow in the chilled water pipeline system. Balancing of heating and cooling systems is performed to ensure that the correct amount of water is present at all consumption points.


Balancing is carried out by building balancing valves into the system, thereby adding adjustable resistance. The pressure losses across the balancing valves should be kept as low as possible, so the pressure loss at the most distant valve is close to zero.


Doing this will help minimize unnecessary power consumption for pump operation during the system’s lifetime. There are two types of balancing valves available static and dynamic. The inlet pressure for a dynamic balancing valve needs to be higher than a certain limit to operate correctly.


Temperature sensor: It is used to sense the temperature of the chilled water flowing in the system. Pressure gauge: It is used to measure the pressure in the system, and according to the pressure created by the pumps, water is distributed in the chilled water pipelines.


Drain valve: It helps to remove the water from the chiller during maintenance and cleaning. It is usually installed in the return water line to provide complete clearance. Gate valve: The gate valve regulates the flow of water in the chiller by opening or closing the supply line.



Pipe Fittings


The chiller water-pipe connections are made using victaulic coupling. Victaulic coupling is a grooved coupling pipe joining system that uses a roll grooving technique to join pipes and pipe joining components. Victaulic pipe couplings are used to connect pipes of various pipe materials and sizes.


A groove is formed on the outside of the pipes near the ends to be joined. Each groove receives a gasket, and these ends are placed inside the coupling housing. The gasket creates a pressure seal on the outside diameter of the pipe.


The gasket sealing is enhanced as the coupling housing is tightened with bolts onto the pipe ends. The grooved method has three benefits:

  • A gasket creates a leak-tight seal,

  • Couplings that hold the pipe together, and

  • Fasteners secure the couplings.


First, the gasket is lubricated and then placed on the connecting pipes. Next, the coupling housing is placed on the gasket and tightened with the bolts provided. Finally, the required torque is applied to the bolts using a torque wrench as per the manufacturer's guidelines.



Electrical Connections


Electrical connections are made to the chiller control system using the prescribed wire as per the manufacturer with all safety precautions. The control system of the chiller is mounted on it or typically supplied by others and integrated into the space provided on it.


Chillers are furnished with many features and factory wired only the mains supply is provided. Electrical connections to the following are required:

• L1, L2, L3 motor starter connectors (three-phase), and

• L1, L2 control circuit connectors. (single-phase).


These connections are made on the terminal blocks located inside the chiller control panel. The manufacturer technician makes control panel internal connections if it is not factory connected. An electrical technician installs disconnect switches or circuit breakers in the distribution panel or board.


The best procedure is:

  • Lockout and Tagout the main distribution board before proceeding with chiller connections,

  • Connect the lugs or rings to both ends of the wires,

  • Connect the wire from the main distribution board to the chiller, and

  • Switch on the mains and check for the voltage and current using a multimeter.


Field wiring is required from the electrical source to disconnect switch or circuit breakers and the terminal blocks in the chiller. As per manuals, the electrical contractor will provide all field wirings with prescribed cable types like copper, aluminum, XPLE (cross-linked polyethylene cable), or armored cables.


The chiller involves a series of connections for the evaporator, condenser, and electrical connections. The chiller water-side connections are made using Victaulic coupling. Electrical connections are made using the prescribed wires or cables and as per manuals with all safety precautions.


 

Finalizing & Testing


By the end of this module, you should be able to:

Describe the evacuation and refrigerant charging of a chiller, Explain post-installation testing, and Describe the insulation on chiller connections. Skip to quiz!


Evacuation Process


Refrigeration systems operate best when the only refrigerant is present in the system. Before charging it with refrigerant, steps must be taken to remove all air, water vapor, and all other noncondensable from the chiller unit. Non-condensables are gases that will not condense into a liquid within the operating temperatures, such as air and nitrogen.


Various operating issues are encountered if air, water vapor, or non-condensables are left in the system. Water will decrease the capacity of the evaporator and cause the formation of ice in the openings, causing restriction or complete shutoff of refrigerant flow.


Air and non-condensables will get collected in the condenser, decreasing the space for condensing liquid and causing pressure rise, thus reducing the capacity. If properly evacuated, the system will be oxygen-free dry, and no non-condensables will cause problems later.


The evacuation should not be done unless the room temperature is 60° F or higher (to allow for proper moisture boil-off). If possible, the piping should not be insulated before the evacuation process is started. Use a high vacuum pump capable of attaining a blanked-off pressure of 10 microns or less.


It is not possible to read high vacuums or low absolute pressures with a pressure gauge or mercury manometer. Use the proper micron gauge manufactured by McLeod, Stokes, Airserco, or some other standard manufacturer. These gauges read in the range of 20 to 20,000 microns.


Evacuation procedure:

1. The vacuum pump is connected to the system and turned on.

2. Allow the pump to operate for five (5) or six (6) hours, as it reduces the system pressure as low as the pump is able to bring it.

3. Stop the system and allow it to stand for approximately twelve (12) hours at low pressure.

4. Break the vacuum with the oil-free dry nitrogen.

5. Allow the pressure in the system to come up to slightly above zero (0) pounds with nitrogen before repeating the evacuation.

6. Evacuate the system below the 500-micron figure and charge with the refrigerant being used for the system.


A single system evacuation is not satisfactory to remove all of the air, water, and non-condensables present. The triple evacuation method is recommended. Repeat the procedure until the pressure is below 500 microns.


Refrigerant Charging


Each unit is shipped with a holding charge to keep the system dry during shipment or storage. If the holding charge is not present in the system at the time of delivery or installation, notify the factory before proceeding. There might be a leak in the system, which must be identified first and then added refrigerant.

All piping in the chiller is 304L stainless steel, and optional 316L piping is also available. Pipes handling refrigerants are provided using copper pipes. Refrigerant connections are provided on the right side of the chiller for standard installation, but they can be reversed as per site requirements.


Standard refrigerant connections are butt weld, but sometimes it is threaded connections. Threaded connections are not recommended but can be supplied if specified. For threaded connections on piping for refrigerants, use Teflon thread sealing tape.


Before adding refrigerant or placing the unit in operation, evacuate the entire system to ensure a completely dry system. Whenever refrigerant is added to any chiller system, extreme care should be taken while charging refrigerant into the system. There are many types of refrigerant, but only prescribed refrigerant is added as per the nameplate.


The chiller should be in operation, and the liquid level observed during the first five minutes of operation and every hour after that until the oil level is stable. With the head pressure (varies with manufacturer) between 180 PSIG and 213 PSIG, additional refrigerant, if required, should be slowly charged into the compressor’s suction as a gas-only (never as a liquid).


Be sure that all charging lines are clean and properly purged of air. Air is purged from the charging line by allowing some refrigerant to escape while attaching the hose to the charging port. When the liquid level in the refrigerant drum or receiver (depending on the system’s configuration) is stable, the unit is fully charged.


The chiller data nameplate lists the unit model, refrigerant type, and refrigerant charge of the evaporator only. Always monitor and record how much refrigerant is added, and additional refrigerant will be required for field piping or other components added to the systems.


Never exceed the refrigerant charge specified by the system supplier. Do not overcharge the refrigerant circuit because this induces high discharge pressures. Be sure the correct type of refrigerant is added to chiller systems.


Testing System


Every chiller has different testing requirements based upon the manufacturer’s guidelines. The standard ones are as follows:

  • Water-side checks,

  • Unit side checks, and

  • Electrical checks.


The water-side checks can be summarized as:


  • All water pipelines should be clean, correctly connected, and with the proper water flow direction,

  • Check inlet or outlet water pipe connections,

  • Ensure the startup water valves are operated,

  • Startup pump before chiller,

  • Check for leakage on the connection joints,

  • Open-air exhaust valve to drain system internal air then close it,

  • Inspect chilled water side pressure losses and check whether the water flow rate is correct, and

  • Inspect whether the inlet and outlet water temperature in the control cabinet is equal to thermometer temp.

Let’s now check the unit.


The basic checks on the unit are:

  • Check whether all safety control equipment like a thermometer, pressure gauge, and actuators are in the initial state, and its setting is correct,

  • Check whether the unit valves are in the correct position,

  • Check whether there is a refrigeration leakage sound,

  • Check whether there is phase loss (phase-ground voltage is 220V),

  • Check whether all local setting set by the control panel is strictly according to requirement,

  • Check whether the compressor oil heater is normal and whether it meets open conditions.

Let’s now check the electrical connections are good.


Electrical connections are checked because if any loose contact is present, it may damage or short circuit the system. The standard checks are:

  • Switch off the main power switch and check all startup circuits and control circuits in the cabinet,

  • The power phase sequence should be equal to the unit nameplate,

  • Check whether the power supply is equal to the unit nameplate to ensure the voltage variation range is not exceeding 10%, and phase voltage unbalance is not exceeding 2%,

  • Check whether compressor resistance is normal (phase resistance, phase-earth resistance),

  • Check whether there is enough electricity supply capacity to meet unit full load running,

  • Check whether the unit is connected to earthing or ground,

  • Check whether the capacity of cable and protector is equal to the unit running demand, and the complete interlock control connection is according to the electrical control diagram, and

  • Check all relays, contactors, and control equipment are in good condition.

Let’s now run the chiller!


If a building is under construction, it requires permission from the local municipality office and must follow the guidelines and codes according to the local codebook. The inspection is required to run the machine safely without any hazards. It will follow specific guidelines that will inspect the complete chiller similar to the manufacturer’s checks.


Post Installation Checks


A trial run is required for every chiller before operating on its full load. Some of the chillers require 6-12 hours of run without any working load. The post-installation checklist is followed before the first run using the manual provided or with the manufacturer technician.


Some of the general steps are:


  • Connect the manifold gauge with the unit and lay the temperature probe, then startup one compressor,

  • Inspect whether the compressor transformer is normal and the voltage of each contactor,

  • Check compressor current usage (amperage),

  • Check whether the rotation direction of each fan is correct and whether running is normal, then inspect the running current (in air-cooled chillers),

  • Inspect whether the oil level is normal and whether capacity adjusting solenoid valve is rightly operated (this can be checked by using any tool to touch the valve and judge if there has magnetism),

  • Let the compressor run at least 20 min then check all parameters and inspect whether suction or discharge pressure is normal,

  • Inspect the opening of the electrical expansion valve according to suction temperature and judge whether it is in the normal range,

  • Inspect whether the suction superheats degree is within 5 - 7℃ and whether the discharge superheats degree and condensation superheat degree is in the normal range,

  • Shut down the unit and check whether the compressor oil level is in the normal range,

  • Enough air conditioning load is needed to keep the unit running and make sure that all air conditioning appliances are on,

  • After the trial run, check all valve bonnets and fasten them,

  • Clean the unit, oil, and dirt in all joints, and

  • Prepare a report of test results with date and time.

Now we are ready to use the chiller!


Chiller piping and equipment operate at temperatures lower than the ambient air, so moisture in the air can condense on the cold surface. Insulation prevents condensation and heat loss to the environment. Insulating chilled water systems require special attention and with prescribed methods as per manufacturer only.


Pipe insulation is designed to do one or more of the following:

  • Conserve energy and help reduce the building,

  • operating cost,

  • Control condensation,

  • Stabilize process performance (process control),

  • Protect personnel by reducing surface temperatures,

  • Reduce emissions, and

  • Reduce noise.


If not, the insulation system can become wet, which can lead to several issues such as:

  • Degradation of the insulation system service life and performance,

  • Corrosion of pipes, valves, and fittings contained within the insulation system, and

  • The potential for mold growth and water-related damage to surrounding materials.


The refrigerant is added to chillers after multiple evacuations and using proper micron gauges. Post-installation check or inspection is required before starting any chiller for water-side, unit side, and electrical connections. Chillers are run first without any load initially for testing and insulated post-testing.


 

Question #1: Which device is used to prevent vibrations from transferring from a chiller to the pipeline?

  1. Gasket

  2. Coupling

  3. Balancing valve

  4. Flexible connection

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Answer: Flexible connection

Flexible connections are used to prevent the vibrations from distributing from the chiller to the pipeline.


Question #2: Which device is used to ensure the proper amount of water flow to the evaporator in chilled water systems before the unit can start or shut down?

  1. Thermometer

  2. Flow switch

  3. Gate valve

  4. Pressure meter

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Answer: Flow switch

The flow switch is included in chilled water systems to ensure the proper amount of water flow to the evaporator before the unit starts or shuts down.


Question #3: Which device is used to control the water flowing in the chilled water pipeline system?

  1. Balancing valve

  2. Panelboard

  3. Expansion valve

  4. Control switch

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Answer: Balancing valve

The balancing valve or double regulatingvalve controls the water flow in the chilled water pipeline system.


Question #4: Which drawings have to be followed during the chiller pipe connections?

  1. Site drawings

  2. Plan view

  3. Schematic drawings

  4. Overall drawings

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Answer: Schematic drawings

Schematic drawings are used during the chiller pipe connections.


Question #5: Which type of coupling is used in water-pipe connections?

  1. PVC coupling

  2. Wire coupling

  3. Y-type coupling

  4. Victaulic coupling

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Answer: Victaulic coupling

The chiller water-pipe connections are made using victaulic coupling.


Question #6: During a victaulic coupling installation, the gasket is _____ first and then placed on the connecting pipes.

  1. Lubricated

  2. Tightened with bolts

  3. Removed

  4. Grooved

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Answer: Lubricated

During a victaulic coupling installation, the gasket is lubricated first and then placed on the connecting pipes.


Question #7: Which common electrical phases are used on a chiller system? (Select all that apply)

  1. No phase

  2. Single-phase

  3. Two-phase

  4. Three-phase

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Answer: Single-phase

Three-phase

Electrical connections to chillers are made by providing:

• L1, L2, L3 motor starter connectors (three-phase), and

• L1, L2 control circuit connectors. (single-phase).


Question #8: Arrange the steps in order.

  1. Connect the wire from the main distribution board to the chiller

  2. Lockout and Tagout the main distribution board before proceeding with chiller connections

  3. Connect the lugs or rings to both ends of the wires

  4. Switch on the mains and check for the voltage and current using a multimeter

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Sequence of order: 2,3,1,4

  • Lockout and Tagout the main distribution board before proceeding with chiller connections,

  • Connect the lugs or rings to both ends of the wires,

  • Connect the wire from the main distribution board to the chiller, and

  • Switch on the mains and check for the voltage and current using a multimeter.


Question #9: Select the tools required during the evacuation process of a chiller. (Select all that apply)

  1. Vacuum pump

  2. Refrigerant cylinder

  3. Motor starter

  4. Micron gauge

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Answer: Vacuum pump

Micron gauge

The evacuation process of a chiller is carried out using a vacuum pump and micron gauge.


Question #10: Before adding refrigerant, ______ entire system to ensure a completely dry system.

  1. Fill with water

  2. Evacuate

  3. Insulate

  4. Power on the chiller

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Answer: Evacuate

Before adding refrigerant, evacuate the entire system to ensure a completely dry system.


Question #11: What will one technician first do soon after installing equipment?

  1. Inspection

  2. Turn unit on

  3. Connect wire connections

  4. Run the pump

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Answer: Inspection

Inspection has to be done soon after installation.


Question #12: What are the chiller testing requirements based upon the manufacturer’s guidelines? (Select all that apply)

  1. Air test

  2. Water-side test

  3. Unit test

  4. Base test

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Answer: Water-side test

Unit test

The basic chiller testing requirements based upon the manufacturer’s guidelines are:

  • Water-side,

  • Unit side, and

  • Electrical connections.


Question #13: During the first run, some of the chillers require how many hours run without any working load?

  1. 1-2 hours

  2. 6-12 hours

  3. 48 hours

  4. 100 hours

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Answer: 6-12 hours

During the first run, some of the chillers require 6-12 hours of run without any working load.


Question #14: What prevents condensation and heat loss to the environment?

  1. Plastic cover

  2. PVC pipe

  3. Valves

  4. Insulation

















Answer: Insulation

Insulation prevents condensation and heat loss to the environment.

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