Trane RT-PRC010-EN Manual page 102

102
Mechanical
Specifications
Outside Air
General
Three outside air options: 100 percent
return air, 0 to 25 percent manually
controlled outside air, and 0-100 percent
fully modulating economizer.
Manual outside air option
Manually controlled outside air damper
shall provide up to 25 percent outside air.
Manual outside air damper shall be set
at desired position at unit start-up.
0-100 percent modulating economizer
option
Operated through the primary
temperature controls to automatically
utilize OA for "free" cooling.
Automatically modulated return and OA
dampers shall maintain proper
temperature in the conditioned space.
Economizer shall be equipped with an
automatic lockout when the outdoor
high ambient temperature is too high for
proper cooling. Minimum position
control shall be standard and adjustable
at the Human Interface Panel or with a
remote potentiometer or through the
building management system. A spring
return motor shall ensure closure of OA
dampers during unit shutdown or power
interruption. Mechanical cooling shall be
available to aid the economizer mode at
any ambient. Low leak economizer
dampers shall be standard with a
leakage rate of 2.5 percent of nominal
airflow (400 CFM/ton) at 1 inch wg. static
pressure.
Ultra low-leak economizer dampers
option
Standard low leak dampers shall be
provided with chlorinated polyvinyl
chloride gasketing added to the damper
blades and rolled stainless steel jamb
seals to the sides of the damper
assembly. Ultra low-leak economizer
dampers shall have a leakage rate of one
percent based on testing data completed
in accordance with AMCA Standard 575
at AMCA Laboratories.
Economizer Control with Comparative
Enthalpy
Used with the fresh air economizer, two
enthalpy sensors are provided to
compare total heat content of the indoor
air and outdoor air to determine the
most efficient air source when
economizing.
Economizer Control with Reference
Enthalpy
Used with the fresh air economizer, an
outdoor enthalpy sensor is provided to
compare the total heat content of
outdoor air to a locally adjustable
setpoint. The setpoint is programmed at
the human interface , or remote human
interface, to determine if the outdoor
enthalpy condition is suitable for
economizer operation.
Economizer Control with Dry Bulb
Used with the fresh air economizer, an
outdoor temperature sensor is included
for comparing the outdoor dry bulb
temperature to a locally adjustable
temperature setpoint. The setpoint is
programmed at the human interface, or
remote human interface, to determine if
outdoor air temperature is suitable for
economizer operation.
RT -PRC010-EN