Below is a standard method statement or procedure which can be used for installation of water chiller on its foundation after it is delivered on the sites. Before starting the activity of chiller installation following tools/equipment shall be arranged:
- Tool Box
- Lifting Equipment (Cranes)
- Electric Drill Machine
- Threading Machine
- Welding/ Brazing Machine (if required)
- Pipe Cutting Machine
- Grinding Machine
- Pressure Gauge
- Water Level Marker
- Mobile Scaffolds
- Staging Platforms
- All the materials received at site shall be as per the approved technical material submittal for Chillers to be inspected upon receipt & approved by the engineer prior in proceeding with the installation. Any discrepancies, damages etc., should be reported to the supplier for rectification or replacement& to be removed from site immediately.
- All construction preliminary inspection/testing works shall be carried out in accordance with the specifications & to be done by qualified Mechanical Engineers and shall be checked and approved by MEP Subcontractor Construction Manager along with QA/QC Engineer.
- Chillers are normally shipped & dispatched from factory as a hermetically assembled package, factory piped, wired and tested. All openings except for the water box vent & drain holes are covered or plugged to prevent contamination during shipment & handling.
- Special care must be taken to ensure that units are offloaded from containers. Rough handling can result in damage to the unit.
- Use appropriate type of vehicles in transporting the units and that they are protected against mechanical & weather damage.
- As soon as the units arrived at site, raise immediate inspection to the consultant & inspect thoroughly for damage. Hence, in case of transit damage, supplier/ manufacturer must be informed immediately.
- Ensure that the units have been inspected & accepted by the consultant as per the approved material submittal prior to offloading & site storage.
Receiving and Storage on Site
- Ensure that the storage location of the units has solid foundation, vibration free, dry, & temperature range shall be -40°F to 158°F.
- It is much recommended not to remove the plastic coverings or packaging materials during the delivery to avoid any corrosion & deterioration.
- Avoid any mechanical shocks and strokes during handling operations. All packages for the equipment reaching the site shall be identified as per package list.
Preliminary Checks Before Chiller Installation
Before commencement of chiller installation activity, the supervisor/ engineer must ensure that:
All Installations & Pressure Testing of Pipe/ Duct works have been completed & approved by the consultant. Determine whether the units occur damages during the storage & shifting of location.
Permission to start or Civil Clearances prior to installation has been given by the main contractor. All relevant Approved Shop drawings for the installation of the equipment shall be available & approved by the consultant.
Installation activities shall only commence when all associated works by the Civil has been completed. Safe access shall be provided by the Main Contractor thru Work Permit in coordination with the Safety in charge at site.
Check the Chiller foundation and ensure it is as per approved drawings. Check the area around the foundation and ensure access to the Chiller from all sides as applicable. Place the anti vibration mount of correct thickness as per approved drawings/submittals.
Ensure that sufficient space between chillers to prevent short cycling of air between the condenser fans of the two chillers. Ensure that electrical isolators are located closed to the chiller for emergency stop/ maintenance. Comply with the civil defense or any other legal requirements.
Ensure that flow switch is provided in the water circuits and interlocked with the chiller. Ensure that isolating valves are provided at the inlet and outlet of the chiller for maintenance. Ensure that a double regulating valve is provided at the chilled water circuit with a flow measuring port to facilitate proper balancing of the water flow.
Safety Requirements for installation of water chiller
The entire assembly of the Water Cooled Centrifugal Chillers will be rigged from store to place of installation i.e. roof etc. Refer to Manufacturer’s Instruction Manual for rigging instructions for the Chiller.
All site safety rules & regulations shall be complied. Supervisors will deliver tool box talks, relevant to these activities to all operatives involved in the installation and shall be recorded. All operatives will be equipped with minimum personnel protective equipment; hard hat, coveralls, safety boots, safety glasses.
The persons using cleaning fluid, solvent cement& any other forms of chemicals have to wear hand gloves. Ensure only qualified personnel shall install, test & commissioned the equipment. During installation, display warning sign boards to be provided and barricade the area whenever necessary. Close monitoring by the site engineers during installation is much highly recommended.
Only competent, experienced & trained personnel shall perform all the required activities stated in this method statement. Ensure that all operatives fully understand the method of these activities.
Sequence of installation for water chiller
Prior to moving the chillers at site, ensure that the foundation requirements have been done. Foundation details & requirements for the chillers shall be as per approved shop drawings or as recommended by the manufacturer as follows:
Rigid non-warping mounting pads or a concrete foundation is available prior to shifting chillers at site. Ensure that the foundation will be able to support the chiller at its full operating weight.
For proper unit operation, the chiller must be level within 1.6 mm over its length & width when set into place on the mounting surface. After ensuring that the foundations for the chillers are satisfactory, shift the chillers by means of cranes to its exact location.
Ensure that the lifting cables are capable of supporting the entire weight of the chiller. Failure to properly lift the unit could result to serious injuries & damage of the unit.
Ensure isolator pads or spring isolators are available in the chiller feet/ legs prior to lowering the unit to its foundation.
Mechanical Connections to Chiller
Ensure that all piping connected to the chiller must be properly isolated & supported so that it does not place any stress on the unit.
It is much recommended to avoid piping from 3 feet minimum to the equipment to allow proper fit-up upon arrival of the unit at job site.
Pipe the evaporator into the chilled water circuit. Pipe the condenser into the cooling tower water circuit. Locate pressure gauge taps in a straight length of pipe. Place tap a minimum of one pipe diameter downstream of any elbow, orifice, etc.
Install air vents & drain valves on the water boxes. Each water box is provided with 3/4” NPTF (National Pipe Thread Female) vent & drain connection. Plastic plugs are factory installed in both openings. Remove & discard the same before installing the water box vents & drain valves.
Install pressure relief valves in the condenser & evaporator water circuits to avoid water box damage due to hydro-static expansion. Whenever are applicable, install pressure relief valves at the drain connections on the evaporator and condenser water boxes. Install a strainer in the entering side of each piping circuit to avoid possible tube plugging in the chiller with debris.
Install flow sensing device. Use either flow switches or differential pressure switches in conjunction with the pump interlocks to verify evaporator and condenser water flows. Install by pass valve system to avoid circulating water through the auxiliary shell when the unit is shut down.
Pipe the evaporator & condenser as per the approved shop drawings. Ensure that the correct pipe sizes are to be connected to the evaporator & condenser circuit. Ensure that the evaporator water piping is clear; check if the chilled water pump is operated but before initial chiller start-up. If any partial blockages exists removed the same to prevent for possible tube damage resulting from evaporator freeze-up or erosion.
For condenser & large evaporator connections, arrange the water piping so that the water supply enters the shell at the lower connection, and exists from the top connection.
Units shall use grooved- pipe connections and flanged connections for 300 psi water boxes, use welded flanges. Piping joined using grooved type couplings, like all types of piping systems; require proper support system to carry out the weight of the pipes & equipment.
Ensure that system refrigerant differential pressure must be maintained above 21 kpa at all times. Failure to do so could result in operating problems. Ensure that the discharge piping that allows pressure relief devices to safely vent refrigerant to the atmosphere if over pressure occurs.
Make sure that the minimum pipe size for the vent must be equals the size of the discharge connections on the pressure relief device. When connecting the vent line to the chiller do not apply threading torque to the outside pipe.
If the unit is not factory insulated, install insulation around the evaporator bulb wells and ensure that the bulb wells and connections for the water box drains and vents are still accessible after insulation is applied. Ensure that the sensor modules and interconnecting four wire cables must be raised up above the field –installed insulation. Do not insulate over the wiring or sensor device. Insulation shall be as per approved material submittal.
Install the controller hardware/ equipment which are used to interface with the internal chiller data & functions provide by the controls. Note that there are four connections on the controller that support the communication interface.
Install the control panel & ensure low voltage & high voltage areas are in proper route & field wiring.
Installation Method of display
The display is boxed and shrink-wrapped behind the control panel during the shipment. Follow the procedure for installation of display as follows:
- Unwrap control panel & display arm.
- Plug the power cable and the Ethernet cable into the bottom of the display.
- Adjust the display support arm so the base plate that attaches to the display is horizontal.
- Position the display with the LCD screen facing up, on top of the display support arm base plate.
- Align the four holes in the display support arm base plate.
- Attach the display to the display support arm base plate.
Electrical Wiring Procedure
Ensure that all wires & cables are of the correct sizes as voltage/ampere requirements of the units. Check the isolator selection/ capacity for the chillers. Check the cable sizing which should be adequate to take the loads.
Check the control wiring scheme for proper interlocking. Cable tray / routing to be checked and coordinated with other services. Details of control scheme, controls, to be given to the control panel supplier and ensure proper arrangement are provided to suit requirement.
Ensure all Electrical requirements have been wired & connected as follows:
- Power supply wiring to the starter
- Starter to motor wiring
- Starter to control panel wiring
- System Control Circuit wiring
- Water pump interlock circuits & flow switches & other devices.
- Temperature Sensor circuits
- Other unit control options present
- Any field supplied control devices
System evacuation, dehydration and charging with refrigerant shall be carried out by skilled & experienced personnel only. After installation of the chillers, raise inspection to the consultant for acceptance prior to proceeding with testing & commissioning.