Step 12 - Route Vav Static Pressure Sensors; Vav Duct Pressure Transducer; Vav Building Pressure Transducer; Step 13 - Install All Accessories - Carrier WeatherMaker 48A020 Installation Instructions Manual

Step 12 — Route VAV Static Pressure Sensors
VAV DUCT PRESSURE TRANSDUCER — The VAV duct
pressure transducer (VAV inverter pressure transducer) is locat-
ed behind the filter access door on the lower inner panel. See
Fig. 44. A section of field-supplied
be run from the high pressure tap on the differential pressure
switch and connected to a field-supplied tap in the supply-air
duct. The tap is usually located
supply duct. Remove plug button in panel to route tubing.
VAV BUILDING PRESSURE TRANSDUCER —
VAV building pressure transducer (modulating power ex-
haust pressure transducer) is located behind the filter ac-
cess door on the lower inner panel. See Fig. 44. A section
of field-supplied / -in. plastic tubing must be run from the
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high pressure tap on the differential pressure switch to the
conditioned space. The pressure tube must be terminated in
the conditioned space where a constant pressure is re-
quired. This location is usually in an entrance lobby so that
the building exterior doors will open and close properly.
Remove plug button in panel to route tubing.
The low pressure tap is factory-routed to the atmosphere. For a
positive-pressure building, route the high tap to building air
and low tap to atmosphere. For a negative-pressure building,
route the high tap to atmosphere and the low tap to building air.
Step 13 — Install All Accessories —
factory-installed options have been adjusted, install all field-in-
stalled accessories. Refer to the accessory installation instruc-
tions included with each accessory.
The 48A Series units have a large number of factory-installed
options which were previously available only as accessories.
Some of the available options can also be installed in the field
if needed. In most cases the units have been pre-wired so that
the accessories can be easily installed. Instructions are shipped
with each accessory. Configuration of the controls for these
accessories as well as the factory-installed options can be
found in the Controls, Start-up, Operation, Service and Trou-
bleshooting book. The following is a list of some of the com-
mon accessories:
• Thermostats and space temperature sensors
• LP (liquid propane) conversion kit
• Accessory barometric relief damper
• Accessory power exhaust
• Non-modulating to modulating power exhaust
• Condenser coil hail guards
• Outdoor humidity sensor (used for economizer enthalpy
changeover)
• Return air humidity sensors (used for economizer differ-
ential enthalpy changeover, factory-installed with
Humidi-MiZer option)
• Return air smoke detector
• Controls expansion module (used for interface to building
management systems, not typically needed on system
with the Carrier Comfort Network
• Plugged filter sensor
• Motormaster ® V low ambient head pressure control
1 / -in. plastic tubing must
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/ of the way out on the main
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3
The
After all the
® [CCN] system)

FIELD-FABRICATED WIND BAFFLES

IMPORTANT: Carrier recommends the installation of
field-fabricated wind baffles on all vertically oriented
condenser coils when operating in environments with
prevailing winds of more than 5 mph and where tem-
peratures drop below 32°F. See the Motormaster
accessory installation guide for instructions.
To avoid the possibility of electrical shock, open all discon-
nects before installing or servicing this accessory.
In areas with prevailing winds of more than 5 mph and where
temperatures drop below 32°F, wind baffles must be field fab-
ricated to ensure proper cooling cycle operation at low-ambi-
ent temperatures with Motormaster V controls. Baffles are not
needed on size 060 units with MCHX (microchannel heat
exchangers). See Fig. 45 for baffle details. Use 20-gage galva-
nized sheet metal, or similar corrosion-resistant material for the
baffles. Use field-supplied screws to attach baffles to unit.
Screws should be 1 / -in. diameter or larger. Screws should not
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be more than 1 / inch in length. Drill required screw holes for
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mounting baffles.
To avoid damage to refrigerant coils, electrical compo-
nents, and wiring use extreme care when drilling screw
holes and screwing in fasteners.
AUXILIARY PRESSURE TRANSDUCERS
(INSIDE OF PANEL)
CONTROL BOX
Fig. 44 — Pressure Transducer Locations
31
WARNING
CAUTION
a48-6976