Carrier WEATHERMASTER 50HJQ004-016 Product Data page 3

Standard 2-in. throwaway filters
are easily accessed through a remov-
able panel located above the air intake
hood. No tools are required to change
unit filters.
All 004-012 units are designed
with a single, continuous top
piece to eliminate leaking at the seams
or gasketing.
Belt-driven indoor-fan motors al-
low maximum on-site flexibility without
changing motors or drives.
Field-installed accessory electric
heaters are available in a wide range of
capacities. An available single-point
wiring kit makes installation simple.
Low voltage wiring connections
are easily made due to the large termi-
nal board which is located for quick,
convenient access.
In addition, color-coded wires permit
easy tracing and diagnostics.
Proven compressor reliability
Design techniques feature computer-
programmed balance between com-
pressor, condenser, and evaporator.
Carrier-specified hermetic compres-
sors are equipped with compressor
overcurrent and overtemperature pro-
tection to ensure dependability.
All units have Carrier's exclusive
Acutrol™ fixed orifice metering device
which precisely controls refrigerant
flow, preventing slugging and flood-
back, while maintaining optimum unit
performance. Refrigerant filter driers
are standard.
Standard low ambient cooling op-
eration to 25 F; optional head pres-
sure control kit available for outdoor
ambient conditions to –20 F.
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Integrated economizers and
outdoor-air dampers
Available as options or accessories,
economizers and manual outdoor-air
dampers introduce outdoor air which
mixes with the conditioned air, improv-
ing indoor-air quality and often reduc-
ing energy consumption.
During a first stage call for cooling, if
the outdoor-air temperature is below
the economizer control changeover set
point, the mixed-air sensor modulates
the economizer outdoor-air damper
open to take advantage of free cooling
provided by the outside air. When
second-stage cooling is called for, the
compressor is energized in addition to
the economizer. If the outdoor-air tem-
perature is above the changeover set
point, the first stage of compression is
activated and the economizer damper
stays at minimum position.
Accessory upgrade kits allow for
control by differential dry-bulb temper-
ature (outdoor vs return), outdoor air
enthalpy changeover, or more precise
differential enthalpy control.
Units can be equipped with different
economizer options to meet specific
controls applications. The factory-
installed or field-installed EconoMi$er
IV and EconoMi$er2 are available. The
EconoMi$er IV is used with the
standard rooftop unit controls and
includes an industry standard, stand-
alone, solid-state control. The control
can be used with a CO sensor for
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DCV (demand control ventilation) op-
eration. For direct digital control (DDC)
applications, the EconoMi$er2 can be
operated using PremierLink™ controls
or a third party controller. The Econo-
Mi$er2 includes 4 to 20 mA actuator
capability for demand control ventila-
tion applications.
All economizers incorporate a paral-
lel blade, gear driven damper system
for efficient air mixing and reliable con-
trol. In addition, the standard damper
actuator includes a spring return to
provide reliable closure on power loss.
The economizers for sizes 004-012
are equipped with up to 100% baro-
metric relief capability for high outdoor
airflow operations. Economizers for
unit sizes 004-014 are available,
factory-installed, for vertical return
only. Economizers for unit sizes 015-
028 are compatible for vertical or hori-
zontal return. An optional field-
installed barometric relief package is
available for 014 and 016 size units.
In addition, single-stage power
exhaust is available as a field-installed
accessory for EconoMi$er IV to help
maintain proper building pressure.
For units without economizer, year-
round ventilation is enhanced by a
manual outdoor-air damper. On size
004-012 units, a 25% or 50% manual
damper is available as a field-installed
accessory. Unit sizes 014 and 016 are
equipped with a manual 25% damper.
Service options
Servicing a rooftop unit has never been
easier with the new factory-installed
905
service options for these rooftop units.
These options include the following:
• Hinged access panels are provided
for the filter/indoor-fan motor,
compressors, indoor fan, and con-
trol box areas. Quick access to
major components is accomplished
by simply unlatching and swinging
open the various panels. Each
hinged panel is permanently
mounted to the unit, thereby elimi-
nating the concern of a dropped or
wind-blown panel puncturing deli-
cate roof materials. The 4 extended
access panels are also equipped
with ''tie back'' retaining devices to
hold the door in the open position
while servicing the unit.
• An external, covered, 115-v
Ground Fault Interrupt (GFI) recep-
tacle is provided as a convenient
power source for drills, lights, refrig-
erant recovery units, or other elec-
trical service tools. Simply connect
the outlet to a field-supplied and
properly fused branch circuit power
supply.
• An integral non-fused disconnect
switch within the rooftop unit
reduces installation time, labor and
material costs. Safety is assured
by an interlock which prevents
access to the control box unless
the switch is in the OFF position.
In addition, the externally mounted
handle incorporates power lockout
capability to further protect service
personnel.
Carrier PremierLink™ con-
trols add reliability, efficiency,
and simplification
The PremierLink direct digital controls
can be ordered as a factory-installed
option or as a field-installed accessory.
Designed and manufactured exclusively
by Carrier, the controls can be used to
actively monitor and control all modes
of operations, as well as monitor the
following diagnostics and features: unit
number, zone temperature, zone set
point, zone humidity set point, dis-
charge air temperatures, fan status,
stages of heating, stages of cooling,
damper position, outdoor-air tempera-
ture, outdoor humidity level, filter
status, fire shutdown status, IAQ
(indoor air quality) set point, enthalpy
status, differential enthalpy status,
heat/cool lockout, cfm set point,
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