Packaged Rooftop Air Conditioners Manual

RT-PRC010-EN96
Options
A full range of factory-installed modular
options are available on standard ship
cycles, allowing your rooftop design to
best suit each individual application.
Cooling Only/Heating Casings
• Cooling Only — Two casing choices are
available, one designed for high airside
efficiency and one for sound sensitive
applications. The 90 to 130 tons are
extended casing only.
• Electric Heat — Nickel-chromium
electric heating elements in
individually fused circuits of 48 amps
or less and with all necessary safeties.
A full range of sizing options is
available.
• Natural Gas Heat -- Two Stage and
Limited Modulation — Two-pass
stainless steel tubular free floating heat
exchanger has industrial type burner
and combustion blower. Available with
high or low fire and UL or CSA
approval.
• Natural Gas Heat - Full Modulation —
The heat exchanger drum, tubes and
front and rear headers are constructed
of the most corrosion resistant
austenitic stainless steel alloys
available.
• Steam Heat — ARI certified type NS
coil with non-freeze steam distribution.
Coils are pitched for drainage and are
provided with steam modulating valve
with actuator. High and low heat
options are available.
• Hot Water Heat — ARI certified type W
coil mounted for drainage and
provided with hot water modulating
valve with actuator. High and low heat
options are available.
Power Supplies
Rooftops are available with 200, 230, 460
and 575 voltage power supplies.
Exhaust
• No Exhaust — Rooftops can be built
for makeup air applications with no
exhaust. Relief opening is sealed
watertight.
• Barometric Relief — Gravity dampers
are provided that open to relieve
positive pressure.
• 50 Percent Exhaust Fan — One double
inlet forward-curved fan can exhaust
up to 50 percent of supply air. Control
is on/off based on economizer damper
position. Barometric dampers at fan
outlet prevent air backdraft.
• 100 Percent Modulating Exhaust Fan —
Two double inlet forward-curved fans
can exhaust up to 100 percent supply
air. Fans operate when economizer
damper is open greater than minimum
position. Discharge dampers at fan
outlet modulate in response to
economizer damper position on
CV rooftops.
• 100 Percent Modulating Exhaust with
Statitrac™ Control — For both CV and
VAV rooftops, the 100 percent
modulating exhaust discharge
dampers are modulated in response to
building pressure. A differential
pressure control system, called
Statitrac™, uses a differential pressure
transducer to compare indoor building
pressure to atmospheric pressure. The
FC exhaust fan is turned on when
required to lower building static
pressure to setpoint. The Statitrac
control system then modulates the
discharge dampers to control the
building pressure to within the
adjustable, specified dead band that is
set at the Human Interface Panel.
Filters
• No Filters (two inch throwaway filter
rack only) — complete set of two-inch
thick filter racks, without the filter
media to accommodate applications
which require field supplied filters.
• No Filters (bag/cartridge with prefilter
filter rack) — long-lasting galvanized
steel frame without the filter media to
accommodate applications which
require field supplied filters.
• Throwaway — Two-inch, 30 percent
efficient throwaway filters, includes
rack as standard.
• Cleanable Wire Mesh — Two-inch
permanent washable wire mesh filters
are provided with metal frame.
• High-Efficiency Throwaway — Two inch
throwaway filters include rack and
have an average arrestance in excess
of 90 percent when tested in
accordance with ASHRAE 52-76.
• 90-95 Percent Bag Filter (with prefilter)
— Glass fiber extended media bag
filter is mounted in a galvanized steel
frame. 90-95 percent dust spot
efficiency. Two-inch throwaway
prefilters are included with this option.
• 90-95 Percent Cartridge Filter (with
prefilter) — These twelve-inch deep
cartridge filters are mounted in a
galvanized steel frame. They are Class 1
listed by Underwriters Laboratories
and have a 90-95 percent dust spot
efficiency per ASHRAE 52-76. To ensure
maximum cartridge filter life, two-inch
prefilters are included.
Fresh Air
• 0 To 25 Percent Manual Outside Air —
Includes outside air opening with
moisture eliminator and manually
positioned damper for drawing up to
25 percent outside air. (20-75 tons only)
• Economizer — Includes the primary
temperature controls necessary to
automatically use outdoor air for free
cooling. Option includes modulating
return and outside air dampers, high
ambient temperature lockout,
minimum position control and spring
return motor. Standard low leak
outside air dampers are provided with
a leakage rate of 2.5 percent of
nominal airflow at one inch W.C. static
pressure. The 0 to 100% fresh air
economizer has three optional
economizer controls available:
comparative enthalpy, reference
enthalpy, or dry bulb control.
System Control
• Constant Volume — Provided with all
the necessary controls to operate
rooftop from a zone sensor, including
CV microprocessor unit control
module, a microprocessor compressor
controller and a unit mounted Human
Interface Panel.
• VAV Supply Air Temperature control
without inlet guide vanes — Provided
with all the necessary controls to
operate a VAV rooftop from the
discharge air temperature, including
discharge air microprocessor controller
and discharge air sensor. The
microprocessor controller coordinates
the economizer control and the stages
of cooling with zone or outdoor air
reset capabilities and an adjustable
control band to fine-tune the control to
specific applications.
Options