48VLU-E, 48VLU-F Ultra Low NOx: Product Data
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
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Guide Specifications
Packaged Gas Heating/Electric Cooling Units
Constant Volume Application
HVAC Guide Specifications
Size Range:
2 to 5 Tons, Nominal Cooling
60,000 to 90,000 Btuh,
Nominal Heating Input
General
SYSTEM DESCRIPTION
Outdoor rooftop mounted, gas heating/electric cooling unit utilizing a
hermetic scroll compressor for cooling duty. Unit shall discharge supply
air vertically or horizontally as shown on contract drawings. Condenser
fan/coil section shall have a draw-thru design with vertical discharge for
minimum sound levels.
QUALITY ASSURANCE
– Unit shall be rated in accordance with AHRI Standards 210/240 and
270-1995.
– Unit shall be designed in accordance with UL Standard 1995 and
ANSI Z 21.47.
– Unit shall be manufactured in a facility registered to ISO 9001
manufacturing quality standard.
– Unit shall be UL listed and c-UL certified as a total package for
safety requirements.
– Roof curb shall be designed to conform to NRCA Standards.
– Insulation and adhesives shall meet NFPA 90.1 requirements for
flame spread and smoke generation.
– Cabinet insulation shall meet ASHRAE Standard 62.2.
DELIVERY, STORAGE AND HANDLING
– Unit shall be stored and handled per manufacturer’s
recommendations.
Products
EQUIPMENT
General
:
Factory-assembled, single-piece, heating and cooling unit. Contained
within the enclosure shall be all factory wiring, piping, controls,
refrigerant charge with R-410A refrigerant, and special features required
prior to field start-up.
Unit Cabinet:
– Unit cabinet shall be constructed of phosphated, zinc-coated,
pre-painted steel capable of with-standing 500 hours in salt spray.
– Normal service shall be through 3 removable cabinet panels.
– The unit shall be constructed on a rust proof unit base that has an
externally trapped, integrated sloped drain.
– Evaporator fan compartment top surface shall be insulated with a
minimum 1/2-in. (12.7 mm) thick, flexible fiberglass insulation,
coated on the air side and retained by adhesive and mechanical
means. The evaporator wall sections will be insulated with a
minimum semi-rigid foil-faced board capable of being wiped clean.
Aluminum foil-faced fiberglass insulation shall be used in the entire
indoor air cavity section.
– Unit shall have a field-supplied condensate trap.
Fans:
– The evaporator fan shall be a multi-speed, direct-drive, as shown on
equipment drawings.
– Fan wheel shall be made from steel, be double-inlet type with
forward curved blades with corrosion resistant finish. Fan wheel
shall be dynamically balanced.
– Condenser fan shall be direct drive propeller type with aluminum
blades riveted to corrosion resistant steel spiders, be dynamically
balanced, and discharge air vertically.
Compressor:
– Fully hermetic compressors with factory-installed vibration
isolation.
Coils:
Evaporator and condenser coils shall have aluminum plate fins
mechanically bonded to seamless copper tubes with all joints brazed.
Tube sheet openings shall be belled to prevent tube wear.
Heating Section:
– Induced-draft combustion type with energy saving direct spark
ignition system and redundant main gas valve.
– Induced-draft motors shall provide adequate airflow for
combustion.
– The heat exchangers shall be constructed of aluminized steel for
corrosion resistance.
– Pre-mixed burners shall be stainless steel and other alloys.
– All gas piping and electric power shall enter the unit cabinet at a
single location.
Refrigerant Components:
Refrigerant expansion device shall be of the TXV (thermostatic
expansion valve) or fixed orifice type.
Filters:
Filter section shall consist of field-installed, throwaway, 1-in. (25 mm)
thick fiberglass filters of commercially available sizes.
Controls and Safeties:
– Unit controls shall be complete with a self-contained low voltage
control circuit.
– Compressors shall incorporate a solid-state compressor protector
that provides reset capability.
Operating Characteristics:
– Unit shall be capable of starting and running at 125
_
F (51
_
C)
ambient outdoor temperature per maximum load criteria of AHRI
Standard 210.
– Compressor with standard controls shall be capable of operation
down to 40
_
F (4
_
C) ambient outdoor temperature.
– Units shall be provided with fan time delay to prevent cold air
delivery before the heat exchanger warms up.
– Unit shall be provided with 60-second fan time delay (single phase
models) after the thermostat is satisfied.
Electrical Requirements:
All unit power wiring shall enter the unit cabinet at a single location.
Motors:
– Compressor motors shall be of the refrigerant-cooled type with
line-break thermal and current overload protection.
– All fan motors shall have permanently lubricated bearings, and
inherent, automatic reset, thermal overload protection.
– Condenser fan motor shall be totally enclosed.
– Evaporator Fan Motor to be ECM Motor.
Compressor Protection:
Solid-state control shall protect compressor by preventing “short
cycling.”
