2.02 CHILLER DESCRIPTION A. The contractor shall furnish and install air-cooled water chiller with screw compressors as shown as scheduled on the contract documents. The chillers shall be installed in accordance with this specification and perform at the specified conditions as scheduled. 2.03 CHILLER OPERATION A. Wide ambient operation; Chiller shall be able to start and operate in ambient conditions from 0⁰F (-18⁰C) to 125⁰F (52⁰C). Wide ambient operation is accomplished with factory installed and tested protection. If field installed wide ambient solution is used, this shall be purchased and installed at contractor expense. B. Chiller shall be capable of operating with a leaving solution temperature range 40⁰F to 68⁰F (4.4 to 20⁰C) without glycol. C. Chiller shall be capable of starting up with 95⁰F (35⁰C) entering fluid temperature to the evaporator. Maximum water temperature that can be circulated with the Chiller not operating is 108⁰F (52⁰C) D. Chiller shall provide evaporator freeze protection and low limit control to avoid low evaporator refrigerant temperature trip-outs during critical periods of chiller operation. Whenever this control is in effect, the controller shall indicate that the chiller is in adaptive mode. If the condition exists for more than 30 seconds, a limit warning alarm relay shall energize. E. Rapid Restartô after power restoration. The Chiller shall be capable of starting in 45 seconds. 2.04 COMPRESSORS A. Construct chiller using semi-hermetic, variable speed drive, helical rotary screw compressor per circuit. B. Provide compressor motor that is suction gas cooled with robust construction and system design protection. C. Provide oil lubrication system with oil charging valve and oil filter to ensure adequate lubrication during starting, stopping, and normal operation. D. Provide compressor heater to evaporate refrigerant returning to compressor during shut down. Energize heater when compressor is not operating. E. Provide compressor with automatic capacity reduction equipment consisting of capacity control via variable speed drive and/or slide valve. Compressor must start unloaded for soft start on motors. F. Chiller shall be capable of operation down to 25% load without hot gas bypass.
