Control System
The Controls supplied and installed on this Project shall be capable of meeting the requirements specified and functions required of them.HVAC Control
All Controls, except those supplied as `Original Equipment' by the equipment manufacturer, shall be the standard product of one control manufacturer.This Sub-Contractor shall be responsible for the correct operating ranges of all controls and the correct setting and adjustments to meet the designed conditions.
The Controls offered shall be either electric, or electronic type and the tenderers shall indicate the type being offered complete with all technical details and catalogues along with the tender.
Controls
Water Cooled Packaged Units
All the Water Cooled Packaged Units shall have individual switchboards at each Plantroom with facilities to switch on/off manually from the individual switchboard in the respective plantrooms.The room temperature control shall be as scheduled below:
a) Systems with Terminal Units
The Air Distribution System with Terminal Units for Control of Temperature of individual zones as shown in the drawings shall be provided with zone Thermostats as shown on the drawings to control individual Terminal Units.
Automatic Zone Control shall be obtained by changing the air volume supplied to the various spaces to be conditioned in direct proportion to the cooling load requirements. When a room thermostat becomes satisfied bypassed room air is relieved to the ceiling return air plenum. Air quantity and static pressure in the entire air distribution system shall remain constant at all times regardless of the volume of air being supplied to individual zones.
b) Compressor Control
The Control of the Compressor automatic on/off of the Water Cooled Packaged Unit shall be achieved by means of a remote setting thermostat located at the main return air entry point to the Plantroom. The units with multiple compressors shall be provided with a thermometers of sufficient steps.
c) Electrical/ Electronic Control Assembly
i) Electrical/Electronic Control Assembly shall contain low voltage control circuit transformer, compressor phase protection fuse or contactor, fan control and a compressor phase protection fuse or contactor, fan control and a compressor motor time circuit. Timer circuit for compressor motor shall prohibit restarting of compressor motor more than once every five minutes. Compressor protection devices shall be automatic reset type.
ii) All other controls and interlock shall be as per schematic drawings and/or performance required of them.
Air Cooled Packaged Units
All the Air Cooled Packaged Units shall have an individual switchboard for each and they shall be switched on/off manually from the individual switchboard in the respective plantrooms. In addition each unit shall be provided indication of run/trip lights for each compressor in the Main Control Room.The room temperature shall be controlled by means of a remote temperature sensing bulb located at the return air point of entry to the plant room. The temperature selection shall be by means of selector switch graduated in degree fahrenheit located in a accessible location in the plantroom.
Electrical/ Electronic control assembly shall contain a low voltage control circuit transformer, compressor phase protection fuse or contactor, fan control and a compressor motor timer circuit. Timer circuit for compressor motor shall prohibit restarting of compressor motor more than once very five minutes. Compressor protection devices shall be automatic reset type.
All other controls and interlock shall be as per schematic drawings, and/or performance required of them.
Condenser Water System
The Cooling Tower(s) and pump(s) shall operate automatically when any of the floor packaged units are switched on.The Condenser Water Pump Operation shall be controlled by means of a flow switch, located at the discharge of the pump only one pump need to operate.
Switchboards
Air Conditioning Switchboards
The Switchboards shall be installed as close to the units as possible as shown on the drawings.The Switchboards shall be provided with stop/start buttons and indicating lights.