Emerson ITR manual Fan Speed Control FSC Head Pressure Control Standard, Design Pressure

Electrical Data

Fan Speed Control (FSC) Head Pressure Control (Standard)

The winter control system for the air-cooled condenser shall be Liebert Fan Speed Control (FSC). The variable speed motor shall turn on at 10% of the supply voltage and modulate in response to head pressure to a full speed of 1050 RPM. It shall be designed with ball bearings, permanent lubrication, and internal overload protection.

The control system shall be complete with transducers, thermostats and electrical control circuit, fac- tory prewired and tested in an integral control panel. The transducer shall automatically sense the head pressure of the compressor and control the variable speed fan on the air-cooled condenser to properly maintain the head pressure.

The fan speed control system shall provide positive start-up and operation in ambient temperature as low as -20°F (-29°C). Included with the fan speed control system shall be a solid state winter start kit as an integral feature of the electronic control panel.

Liebert Lee-Temp Head Pressure Control (Optional)

The winter control system for the air-cooled condenser shall be “Liebert Lee-Temp.” The Liebert Lee- Temp system shall allow startup and positive head pressure control with ambient temperatures as low as -30°F (-34.4°C). The Liebert Lee-Temp package shall include: insulated receiver, pressure relief valve for each circuit, head pressure three-way control valve, and rotalock valve for isolating the refrigerant charge. The Lee- Temp receiver shall be factory insulated and mounted ready for the field connection to the air-cooled condenser. The Liebert Lee-Temp heater shall be (150) (300) _____ Watt

and require a separate power supply of (115) (230) _____ Volt, single phase, _____ Hz.

Centrifugal Fan Condenser (Optional)

The system shall be supplied with a centrifugal fan condenser (LCC). The condenser shall be con- structed of galvanized steel with a copper tube, aluminum fin coil. The heavy duty fan shall be the centrifugal type, double width, double inlet. The 1750 RPM (1450 RPM @ 50 Hz) fan motor shall be mounted on an adjustable base, and equipped with an adjustable motor pulley. A Liebert Lee- Temp head pressure control system shall be field piped to the unit. Electrical controls shall be in a rain- tight enclosure.

The system shall be designed for _____ °F (°C) ambient. The air-cooled condenser shall have a _____

Volt, 3 phase, _____ Hz power supply.

2.2.2Water or Glycol-Cooled Self-Contained Systems

Indoor Unit Condenser

The water/glycol system shall be equipped with a coaxial condenser having a total pressure drop of

_____ ft. of water (kPa) and a flow rate of _____ GPM (l/s) with _____ °F (°C) entering water/glycol temperature.

Two-way Water Regulating Valve with Bypass (Standard)

The condenser circuit shall be pre-piped with a headpressure actuated two-way regulating valve with bypass.

Three-Way Water Regulating Valve (Optional)

The condenser circuit shall be pre-piped with a head pressure actuated three-way regulating valve.

Design Pressure

The condenser water/glycol circuit shall be designed for a pressure of [(150 PSI (1034 kPa)) (350 PSI (2413 kPa))].

Crankcase Heater (Optional)

A crankcase heater is provided to prevent the migration of refrigerant to the compressor during off cycles.

Hot Gas Reheat (Optional)

The complete hot gas reheat system shall include a copper tube, aluminum fin coil, three-way sole- noid valve, and refrigerant check valve. The capacity of the coil shall be _____ BTU/HR (kW).

70/30 Cu-Ni Econ-O-Coil

This coil replaces the standard copper tube coil to provide improved resistance to corrosion.

This option must be specified whenever a GLYCOOL or Dual Cooling Source system is applied to a cooling tower loop or other open water system.

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