Major System Components; Constant Volume (Cv) Units; Variable Air Volume (Vav) Units; Installation - Carrier Omnizone 50BVC Installation, Start-Up, Service And Controls Operation And Troubleshooting

installation. Modular units are built using an unpainted, galva-
nized steel cabinet with steel framework, and can be easily dis-
assembled without breaking the refrigerant lines. See Table 1
for a model number reference by application.
Each unit contains multiple scroll compressors piped in
separate refrigerant circuits. Each water-cooled circuit includes
a coaxial (tube-in-tube) condenser, TXV (thermostatic expan-
sion valve), individual evaporator coils, and all interconnecting
piping. Water-cooled units are shipped fully charged with
refrigerant. Remote air-cooled units are shipped with a nitrogen
holding charge.
Each unit is equipped with one or two forward-curved cen-
trifugal blowers, to ensure quiet air delivery to the conditioned
space. Constant volume units operate at a single, adjustable fan
speed and provide zone temperature control using a standard
commercial thermostat. For VAV applications, the unit is sup-
plied with a variable frequency drive(s) (VFD) that automati-
cally adjusts blower speed to maintain a constant, adjustable
duct static pressure. Compressors are automatically staged to
provide supply air temperature control (VAV applications) or
zone temperature control using a two-stage commercial ther-
mostat (CV applications).
The 50BV units have removable access panels for easy
servicing. These panels allow access to controls, compressors,
condensers, VFD(s) (if applicable), evaporator motors, blow-
ers, belts, pulleys, and refrigeration components.

MAJOR SYSTEM COMPONENTS

Constant Volume (CV) Units

MAIN CONTROL BOARD (MCB) — The main control
board for the 50BVC, Q, T, and V units provides both controls
and diagnostics including:
• Condensate Overflow Protection prevents unit operation in
the event that the drain pan clogs.
• Random Start provides a programmable start with a range
of 30 to 60 seconds.
• Anti-short Cycle Timer provides a 5-minute delay to pre-
vent compressor short cycling.
• Low Pressure Bypass Timer bypasses the low-pressure
switch for 120 seconds to avoid nuisance trips during cold
start-up.
• Brownout/Surge/Power Interruption Protection will shut
down the main control board functions if the secondary
voltage falls below 18 volts or goes above 30 volts. A blink
code will flash while in fault mode. This will automatically
reset when the voltage returns to the valid range.
• Alarm Output contacts provide remote fault indication.
• Test/Service Pin is a jumper that reduces all time delay
settings to 6 seconds during troubleshooting or operation
verification.
• Reset occurs after a 5-minute delay when a fault condition
occurs. When the timer expires, the unit will restart. If the
same condition occurs a second time, the unit will be locked
out.
MODEL
50BVC Water-Cooled
50BVQ Water-Cooled Heat Pump
50BVJ Water-Cooled
50BVT Water-Cooled
50BVV Water-Cooled Heat Pump
50BVW Water-Cooled
LEGEND
CV — Constant Volume
VAV — Variable Air Volume
Table 1 — Model Number Reference By Application Type
TYPE*
• Lockout Reset requires that the unit power be cycled at the
unit controller via either the thermostat or unit disconnect.
NOTE: The refrigerant circuits on dual compressor models
are completely independent. If either stage has a fault condi-
tion the remaining stage will continue to operate without
interruption. A freeze or condensate overflow lockout will shut
down both refrigerant circuits.
• LEDs are provided for diagnostic purposes.
• Freeze protection will shut down the compressor circuit if
the refrigerant liquid temperature to the water to refrigerant
heat exchanger falls below 26 F for 30 seconds continuous.
This trip point can be lowered to 15 F for geothermal appli-
cations employing antifreeze by cutting the JP1 and JP2
jumpers on the board.
Variable Air Volume (VAV) Units —
W units come equipped with a Carrier I/O Flex 6126 controller
and a VFD.
NOTE: The VAV units utilize face split coils and should not
be operated below 50% of nominal airflow to prevent coil
freezing.
Omnizone™ 50BV units are intended for indoor installa-
tion only. Determine building alterations required to run piping,
wiring, and ductwork. Read all installation instructions before
installing the unit.
Step 1 — Complete Pre-Installation Checks
EXAMINE THE UNIT — Examine the unit for shipping
damage. File a claim with the transit company if damage is
found. Check the shipment for completeness. Verify that the
nameplate electrical requirements match the available power
supply.
UNIT STORAGE — The 50BV units are designed and pack-
aged for indoor storage and use only. If the equipment is not
needed for immediate installation upon its arrival at the job site,
it should be left in its shipping carton and stored in a clean, dry
area. Units must only be stored or moved in the normal upright
position, as indicated by the "UP" arrows on each carton, at all
times. DO NOT STACK UNITS.
MODULAR UNITS — The 50BVT, V, W units are shipped in
multiple sections for easy movement and installation. The sepa-
rate modules of the High Boy units will pass through a standard
36-in. steel framed door or service elevator. The modules of a
Low Boy unit will not. Circuit integrity is maintained because
none of the refrigerant piping requires disconnection. Water pip-
ing connections are made with the use of heavy-duty bronze-
bodied unions so no field welding or brazing is required.
NOTE: High-boy units ship as two pieces (air-conditioning/
filter section and blower section) and can be disassembled into
6 pieces. Low-boy units ship complete and will not fit through
a 36 in. door. The low-boy unit's filter section is integral to unit
and cannot be disassembled.
AVAILABLE CAPACITY
18 to 30 nominal tons
18 to 30 nominal tons
18 to 30 nominal tons
30 to 60 nominal tons
30 to 60 nominal tons
30 to 60 nominal tons
*All units are cooling only unless specified.
3
The 50BVJ and

INSTALLATION

CONSTRUCTION CONTROLS
Single-piece
Single-piece
Single-piece
Modular
Modular
Modular
CV
CV
VAV
CV
CV
VAV