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or steam/hot water). The conditioned outdoor air is discharged
from the supply fan through a vertical or horizontal supply open
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ing. There is no return air opening on 62X Series units with supply
only configurations.
For 62X units without the energy recovery system, the outdoor air
passes through a filtration device and is conditioned using either
direct expansion (DX) cooling (with optional liquid subcooling
and/or hot gas reheat) or optional heating (electric, gas, or steam/
hot water). The conditioned outdoor air is discharged from the
supply fan through a vertical or horizontal supply opening. Air can
be returned to the unit through an optional vertical return air open
-
ing and can be exhausted from the unit by an optional exhaust fan.
There is no recirculation of return air to the space.
For 62X units with the energy recovery ventilator, the outdoor air
passes through a filtration device and enters the energy recovery
device. The outdoor air is preconditioned by the energy recovery
device by transferring energy to or from the return air. The outdoor
air is then conditioned using direct expansion (DX) cooling (with
optional liquid subcooling and/or hot gas reheat) or optional heat
-
ing (electric, gas, or steam/hot water). The conditioned outdoor air
is discharged from the supply fan through a vertical or horizontal
supply opening. Air is returned to the unit through a vertical return
air opening and passes through a filtration device (if equipped).
The return air passes through the energy recovery wheel, where
heat is transferred to or from the supply air, and is exhausted from
the unit. There is no recirculation of return air to the space.
Refrigeration System
All Carrier dedicated outdoor air units utilize highly efficient
scroll compressors that have been optimally designed for use with
Puron
®
refrigerant (R-410A). All 62X units will have a variable
capacity compressor on the lead circuit, either digital (3-18 tons)
or inverter driven (20+ tons). Digital compressors shall be capable
of modulating from 20-100% of nominal compressor capacity. In
-
verter driven compressors shall be capable of modulating from 58-
100% of nominal compressor capacity. All circuits with inverter
compressors shall be equipped with minimum load control valve.
Digital scroll type compressors utilize an external control board to
provide compressor safeties and control compressor modulation.
An onboard solenoid is used to unload the compressor. When the
solenoid is closed, the compressor is loaded. When the solenoid is
open, the compressor is unloaded.
A TXV (thermostatic expansion valve) metering device is used on
all systems.
The refrigeration system includes a hot gas bypass valve with all
standard scroll compressors and with inverter driven compressors.
EVAPORATOR
The 62X Series units utilize a 6-row aluminum/copper evaporator
coil, with 12 fins per inch. Evaporator coils are available with op
-
tional harsh environment coating.
CONDENSER
The 62X Series units utilize a microchannel condenser coil, with
12 fins per inch. Condenser coils are available with optional harsh
environment coating. Condenser fans will be variable speed and
will utilize a variable frequency drive (VFD) to modulate speed
based on head pressure.
REHEAT SYSTEM
The 62X Series units are standard with modulating hot gas reheat
(HGRH) with an optional liquid subcooling. The HGRH system
consists of a full faced coil that is fed hot refrigerant gas by lead
circuit or by all circuits. The HGRH is a modulating type control.
The liquid subcooling and HGRH system features two full faced
coils. The first coil is used for liquid subcooling, and is fed warm
liquid gas by all available circuits. The liquid subcooling coil
uses cycling (on/off) type control. The second coil is used for
HGRH, and is fed hot refrigerant gas by the lead circuit. The
HGRH is a modulating type control. Liquid subcooling or
HGRH coils are available with optional harsh environment
coating.
Heating System
The 62X Series units are available with optional electric, gas, hot
water, or steam heating (special order).
GAS HEAT
The optional gas heating system consists of a factory-installed nat
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ural gas or liquefied petroleum (LP) heat insert with tubular, stain
-
less steel heat exchangers and in-shot burners. All heaters are 80%
efficient (at sea level) and are available in multiple input ratings,
ranging from 75 to 1200 MBtuh. The heater can utilize either a 2-
stage, 4-stage, or modulating gas control valve. Modulating valves
can be 5:1 (20 to 100%) or 10:1 (10 to 100%) turndown. Heat ex
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changers are available with optional harsh environment coating.
The gas heater is natural gas or can have LP factory-installed.
ELECTRIC HEAT
The optional electric heating system consists of a factory-installed
electric heat insert with low watt density coiled heating elements
and stainless steel terminals. The electric heater is available in
multiple output ratings, ranging from 5 to 120 kW (at 230/460V).
The heater control is accomplished by staging (1, 2, or 4 stages) or
by modulation silicon controlled rectifier (SCR).
HOT WATER HEAT
The optional hot water heating system consists of a factory-
installed, four-row hot water coil. The hot water control valve
must be field provided and installed. The hot water coil is avail
-
able with optional harsh environmental coating.