Lennox GCS16-823

Page 49
Optional differential enthalpy control may be added to any
economizer to monitor both indoor and outdoor air condi
tions. With differential enthalpy installed, the economizer
selects the lowest of the two enthalpy conditions to satisfy
cooling demand.
1-REMD16M Downflow Economizer
(all units)
The REMD16M economizer is designed for standard
(downflow) use with units. In 15 ton and larger units, the
economizer can also be adapted to horizontal discharge. In
12.5 ton and smaller units, the REMD16M cannot be con
verted to horizontal discharge and a separate horizontal
economizer (EMDH16M) is used for horizontal applica
tions. Both applications are shown in figure 51. The econo
mizer monitors outdoor air conditions and opens the out
door air dampers to allow 0 to 100 percent outdoor air to be
used for cooling when outdoor humidity and temperature
are acceptable. Damper position continually adjusts to out
door conditions. Additional (second stage) cooling demand
is shifted to the first stage compressor while the dampers
remain open to provide first stage cooling. If outdoor air be
comes unacceptable, the outdoor air dampers close to a
predetermined minimum position while the compressor
cooling circuit cycles as needed. First stage cooling is
shifted back to the first stage compressor and second stage
cooling is directed to the second stage compressor.
FIGURE 49
REMD16M DOWNFLOW ECONOMIZER
ONEPIECE DESIGN FOR
12.5TON AND SMALLER
UNITS
OPTIONAL GED16
GRAVITY EXHAUST DAMPER
Refer to the REMD16M installation instruction for specific
installation details. Refer to the operation sequence (in back
of this manual) for detailed economizer operation. Operation
sequence flowcharts also describe how the economizer in
teracts with the GCS16 and the control system being used.
FIGURE 50
TYPICAL REMD16M ECONOMIZER
FOR 12.5 TON AND SMALLER UNITS
SHOWN INSTALLED
Unit
REMD16M
FIGURE 51
REMD16M-185
(horizontal application)
CHA16-1853
OUTDOOR AIR
DAMPERS
AIR FILTERS
GRAVITY EXHAUST
DAMPERS
REMD16M-185
(downflow application)
OUTDOOR AIR
DAMPERS
AIR FILTERS
GRAVITY EXHAUST
DAMPERS
CHA16-183