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FORM 145.05-EG2 (618)
JOHNSON CONTROLS
75
For units with less than four compressors, one modulating compressor with a minimum
of three stages shall be provided for proper operation at low loads. Unit shall have a mini-
mum of two compressors.
CONDENSERS
Water-Cooled condensers shall utilize high-efficiency, compact, mechanically cleanable
shell and tube design. The condenser shall have removable water heads to clean tubes.
The condenser shall be constructed of enhanced, heavy-walled 5/8-inch OD copper tubes.
The condenser shall have independent refrigerant circuits with a common water supply.
Condensers shall be rated for 560 psig refrigerant and 300 psig
[400 psig]
waterside
working pressure. Valve package shall be factory piped and completed condenser and
piping assembly shall be leak tested at the factory.
UNIT EFFICIENCY
Provide Water-Cooled Self-Contained units to meet the scheduled efficiency levels with
a minimum EER of 12.6.
CONTROLS
The unit shall be controlled by a stand-alone 32 bit microprocessor based controller. The
controller along with all applicable sensors, transducers, and end devices shall be factory
packaged, installed, and fully tested before shipment to insure reliable operation.
The control system shall include a keypad with 36 keys and 2 line x 40 character LCD
display to be used as operator interface. All text and messages displayed shall be in plain
English. The user interface shall provide, at a minimum, the following information:
Setpoints
• Supply Air Temperature
• Morning Warm up / Occupied Heating Temperature
• Unoccupied Heating Temperature
• Duct Pressure
• Supply Air Temperature Reset via Outside Air Temperature
• Supply Air Temperature Reset via Return Air Temperature
• Supply Air Temperature Reset via VFD Speed (variable air volume (VAV) only)
• Supply Air Temperature Reset Limits
Safeties
• Low Suction Pressure (1 per compressor)
• High Discharge Pressure (1 per compressor)
• Compressor Motor Overload (1 per compressor)
• Supply Fan Fail
• Low Entering Air Temperature
Summary of Contents for L-Series
Page 1: ...FORM 145 05 EG2 618 ENGINEERING GUIDE Water Cooled Self Contained Units L Series Vertical ...
Page 4: ...FORM 145 05 EG2 618 4 JOHNSON CONTROLS THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 14: ...FORM 145 05 EG2 618 14 JOHNSON CONTROLS THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 35: ...FORM 145 05 EG2 618 JOHNSON CONTROLS 35 OVERVIEW OF SERVICE CLEARANCES LSWU025 040 MODELS ...