FORM 145.05-EG2 (618)
JOHNSON CONTROLS
79
expansion valves.
Head Pressure Control with Two Two-Way Valves
When the entering condenser water temperature is below 55 ºF and/or the use of waterside
economizer is not available, two factory installed and controlled modulating head pres-
sure control two-way valves shall be provided. Valve actuators shall be controlled through
the factory installed main unit control system to maintain refrigerant head pressure by
reducing the water flow as necessary through to allow proper functioning of thermostatic
expansion valves. The second two valve shall open to divert condenser water to the unit
outlet, minimizing the fluctuations in total water flow.
Condenser Water Flow Switch
When unit is the mechanical cooling mode, compressors shall be enabled when the con-
denser water switch is made. Mechanical cooling shall be disabled when the condenser
water flow switch opens during the operation for longer than 10 seconds, and all compres-
sors shall be turned off.
Dirty Filter Switch
A factory installed and wired pressure switch senses the air pressure differential across
the filters. When the differential pressure exceeds 1.0 iwg (adjustable), the normally open
contacts close. This signals the unit controller that the filters are loaded and are in need
of a change.
Duct High Pressure Limit Switch
Factory installed and wired pressure switch senses the air pressure differential between
the unit inlet and fan outlet. When the differential exceeds the set point for safe operation
of the duct system and the unit, the unit is shut off and an alarm is generated.
Duct Static Pressure Sensor
Factory installed and wired pressure switch senses the air pressure differential between
static pressure inside the duct and outside the duct at the same location. Two pneumatic
tubes from the inside and outside of the duct are to be field installed. The duct static pres-
sure sensor will then control optional VFD speed. Additional duct static pressure sensor
will be available with accompanying logic if the duct static pressures at two different loca-
tions are to be monitored and used to control the VFD speed.
FACTORY TEST
Each unit shall undergo a rigorous factory-run test prior to shipment and factory test
sheets shall be available upon request. The factory test shall include dynamic balancing of
the completed fan assembly, a compressor run check, a complete run test of all electrical
components and safeties, a leak check of all refrigerant circuits, a leak check of all water
circuits, and a final unit inspection.
AGENCY LISTING
The unit shall have ETL US/Canada listed by Intertek Testing Services, Inc.
SERVICE CLEARANCE REQUIREMENTS
Service Clearance requirements on all four sides shall be indicated clearly on the submit-
tal drawings. Optionally, Unit shall require NO MORE THAN 3 inches of clearance on
two sides so that the unit may be placed in a corner.
Содержание L-Series
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Страница 33: ...FORM 145 05 EG2 618 JOHNSON CONTROLS 33 Dimensional Data OVERVIEW OF COMBINED UNIT LSWU025 040 MODELS ...
Страница 34: ...FORM 145 05 EG2 618 34 JOHNSON CONTROLS Dimensional Data Cont d OVERVIEW OF SPLIT SHIPMENT LSWU025 040 MODELS ...
Страница 35: ...FORM 145 05 EG2 618 JOHNSON CONTROLS 35 OVERVIEW OF SERVICE CLEARANCES LSWU025 040 MODELS ...
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