Carrier Omnizone 50BVC Installation, Start-Up, Service And Controls Operation And Troubleshooting page 3

product. Refer to the individual instructions packaged with the kits
or accessories when installing.
WARNING
Before performing service or maintenance operations on unit,
turn off main power switch to unit and open all disconnects.
More than one disconnect switch may be required to de-ener-
gize this equipment. Electric shock hazard can cause injury or
death.
CAUTION
Use care in handling, rigging, and setting bulky equipment.
WARNING
DO NOT USE TORCH to remove any component. System
contains oil and refrigerant under pressure.
To remove a component, wear protective gloves and goggles
and proceed as follows:
a. Shut off electrical power to unit.
b. Recover refrigerant to relieve all pressure from system
using both high-pressure and low pressure ports.
c. Traces of vapor should be displaced with nitrogen and
the work area should be well ventilated. Refrigerant in
contact with an open flame produces toxic gases.
d. Cut component connection tubing with tubing cutter and
remove component from unit. Use a pan to catch any oil
that may come out of the lines and as a gage for how
much oil to add to the system.
e. Carefully un-sweat remaining tubing stubs when neces-
sary. Oil can ignite when exposed to torch flame.
Failure to follow these procedures may result in personal inju-
ry or death.
CAUTION
DO NOT re-use compressor oil or any oil that has been ex-
posed to the atmosphere. Dispose of oil per local codes and
regulations. DO NOT leave refrigerant system open to air any
longer than the actual time required to service the equipment.
Seal circuits being serviced and charge with dry nitrogen to
prevent oil contamination when timely repairs cannot be com-
pleted. Failure to follow these procedures may result in dam-
age to equipment.
GENERAL
Omnizone™ 50BV Indoor Packaged units are very flexible for a
variety of applications. These self-contained units are available as
water source cooling only and heat pump units. The 50BV units
are available with either constant volume (CV) or variable air vol-
ume (VAV) controls. Finally, Omnizone 50BV units are available
in two cabinet styles. Unit sizes 020-034 are constructed in a
single-piece, unpainted galvanized cabinet. Unit sizes 034-064 are
available as modular units, and can be taken apart for easier instal-
lation. Modular units are built using an unpainted, galvanized steel
cabinet with steel framework, and can be easily disassembled
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 expansion valve),
individual evaporator coils, and all interconnecting piping. Water
source units are shipped fully charged with Puron
refrigerant.
Each unit is equipped with one or two forward-curved centrifugal
blowers, to ensure quiet air delivery to the conditioned space.
Constant volume units are equipped with a non-inverter rated sup-
ply fan motor and operate at a single fan speed. Single piece units
include adjustable sheave that can be field adjusted to change the
airflow rate. Modular units include a fixed sheave. For VAV appli-
cations, the unit is supplied with an inverter duty motor with vari-
able frequency drive(s) (VFD) that automatically adjusts blower
speed to maintain a constant, adjustable duct static pressure.
Constant volume units can be controlled by a field provided two-
stage cooling only (50BVC,T) or two-stage heat pump
(50BVQ,V) thermostat or field provided digital controller.
VAV units include a digital VAV controller that provides compres-
sor staging (two or four stages) based on return air temperature
and supply air temperature set points for multi-zone VAV opera-
tion.
All 50BV units have removable access panels for easy servicing.
These panels allow access to controls, compressors, condensers,
VFD(s) (if applicable), evaporator motors, blowers, belts, pulleys,
and refrigeration components.
MAJOR CONTROL COMPONENTS
Constant Volume (CV) Units
UNIT PROTECTION MODULE (UPM)
The UPM for the 50BVC, Q, T, and V units provides both equip-
ment safety and diagnostics capability 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 auto-
matically 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.
• 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 or quad compressor mod-
els are completely independent. If either stage has a fault condition
the remaining stage will continue to operate without interruption.
A freeze or condensate overflow lockout will shut down all refrig-
erant circuits.
• LEDs are provided for diagnostic purposes.
• Freeze protection will shut down the compressor circuit if
the refrigerant liquid temperature to the water to refriger-
ant heat exchanger falls below 26°F for 30 seconds contin-
uous. This trip point can be lowered to 15°F for geother-
mal applications employing antifreeze by cutting the JP1
and JP2 jumpers on the board.
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® (R-410A)