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LGH/LCH036, 048, 060, 072, 074
D-Adjusting Unit CFM - Ultra High Efficiency Direct
Drive Blowers
The supply CFM can be adjusted by changing Unit
Controller settings. Refer to table 7 for menu paths and
default settings. Record any CFM changes on the
parameter settings label located on the inside of the
compressor access panel.
CAUTION
The BLOWER CALIBRATION process starts the in
door blower at operational speeds and moves the
economizer damper blades. Before starting this pro
cess, replace any access panels and close all unit
doors except compressor compartment door.
Blower calibration is required only on units that are newly
installed or if there is a change in the duct work or air filters
after installation. After the new CFM values are entered,
use the down and up arrow buttons to select START
CALIBRATION. Push SAVE to start calibration. The
blower calibration status is displayed as a % complete.
Upon successful completion, the Unit Controller will
display CALIBRATION SUCCESS and go back to the
blower calibration screen. Press the MAIN MENU button
to go to the main menu and press the BACK button to go
to the status screen.
If only the CFM values are updated, use the down and up
arrow buttons to select “CALIBRATION DONE”. Push
SAVE to enter the updated values. This selection will not
initiate calibration, resulting in less setup time. Press the
MAIN MENU button to go to the main menu and press the
BACK button to go to the status screen.
IMPORTANT - On ultra high efficiency units, the default
value for Cooling Low CFM is lower than a traditional
singe- or two-speed unit. If operating the unit with a 2- or
3-stage controller (2- or 3-stage thermostat, DDC
controller, etc.), it is recommended to increase the
Cooling Low CFM default value to a suitable level for
part load cooling (typically 60% of full load CFM).
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