Guide Specifications
7
3.0
G
UIDE
S
PECIFICATIONS
3.1
General
Each condenser shall consist of housing, condenser coil, propeller fans direct-driven by individual fan
motors, fan guards, electrical controls and mounting legs. The air-cooled condenser shall have a
_____volt, 3-phase, _____ Hz power supply.
3.2
Coil
Liebert manufactured coil shall be constructed of copper tubes in a staggered tube pattern. Tubes are
expanded into continuous, corrugated aluminum fins. The fins have full depth fin collars completely
covering the copper tubes, which are connected to heavy wall Type "L" headers. Inlet coil connector
tubes pass through relieved holes in the tube sheet for maximum resistance to piping strain and
vibration. Coils are factory leak-tested at a minimum of 300 psig (2068kPag), dehydrated, then filled
with a nitrogen holding charge and sealed for shipment.
3.3
Fans
Fans shall have aluminum blades secured to corrosion protected steel hubs. Fans shall be secured to
the fan shaft by means of a heavy-duty keyed hub and dual setscrews. Fan diameter shall be 26"
(660mm) or less. Fans shall be factory balanced and run before shipment. Fan guards shall be heavy
gauge, close-meshed steel wire with corrosion resistant PVC finish that shall be rated to pass a
675-hour salt spray test.
3.4
Fan Motors
The variable speed fan motor shall be an inverter duty motor with permanently lubricated ceramic
bearings. The Liebert variable frequency drive control system shall provide overload protection for
the variable speed motor. Each ambient-temperature-controlled fan motor shall have built-in over-
load protection. All motors shall have rain slingers, permanently lubricated bearings and shall be rig-
idly mounted on die-formed galvanized steel supports.
3.5
Head Pressure Control
The Liebert VFD Condenser control system shall include a variable frequency drive, inverter duty fan
motor operating from 0% to 100% motor RPM based on head pressure, refrigerant pressure transduc-
ers, ambient-temperature thermostat(s), motor overload protection and electrical control circuit, fac-
tory-wired in the control panel. VFD control shall be furnished on the fan adjacent to the connection
end of the condenser, which runs continuously with the compressors. Other condenser fans shall be
controlled by ambient thermostats and are either On or Off. This system permits operation at temper-
atures as low as -20°F (-28.9°C).
3.6
Housing
The condenser housing shall be constructed of bright aluminum sheet and divided into individual fan
sections by full width baffles. Structural support members, including coil support frame, motor and
drive support, are galvanized steel for strength and corrosion resistance. Aluminum legs are provided
with rigging holes for hoisting the unit into position.
3.7
TVSS and Unit Disconnect Switch
Transient Voltage Surge Suppression and locking disconnect shall be factory-installed and wired in
the enclosed condenser electrical panel section.
3.8
Alarm Contacts
Normally open, dry contacts shall be provided for indication of VFD and TVSS alarm condition.
3.9
Electrical Controls
All electrical connections and controls shall be provided in a weatherproof enclosure. The enclosure
shall be integral with the condenser for pleasing appearance as well as functional protection.
