24
INSTALLATION
The round barometric bypass damper can be installed in any position.
This damper is factory set for horizontal installation and can be field
modified for vertical installation. Do not run speed screws into damper
housing. Screws may interfere with damper travel. Make sure counter
weight is not obstructed in any way.
a)
Install the bypass damper between the supply and return
plenums of the unit. It must be the first tap off the supply plenum.
b)
Be sure the air flows through the damper in the proper direc-
tion as indicated by the arrow on the damper. Airflow is always
from supply to return plenum. Be certain the damper shaft
is horizontal.
c) Loosen counter weight with allen wrench.
d)
Loosen lever arm from damper shaft and allow to hang straight
down.
e)
Fully close damper by grabbing damper shaft on side attached
to lever arm and turning clockwise until it stops.
f)
While holding the damper fully closed, rotate the lever arm a
little to the right (facing the damper) and then screw in to
tighten to the damper shaft. Then tighten lock nut.
g)
Be sure the damper is being held closed by the counter weight.
Proceed to set up.
BAROMETRIC BYPASS SETUP
a)
Turn off all thermostats.
b)
Turn on Switching Center/Controller and set fan switch to “ON”
position. Allow fan to run for 5 minutes to equalize pressure.
Then make sure all dampers are open by checking for air flow
out of each damper.
c)
By moving counter weight up or down the lever arm, adjust it
so that the damper just wants to start opening.
d)
If the damper cannot be held closed with the counter weight all
the way at the bottom of the lever arm, then hold the damper
shaft, loosen the lever arm from the damper shaft, and rotate
the lever arm further to the right and retighten. Repeat Step C.
e)
The barometric bypass damper is now calibrated.
BAROMETRIC BYPASS STARTUP TEST
a)
Have at least half of the zones call for either heating or cooling.
b)
Check to be sure the calling zone dampers are open, (air is
flowing).
c)
Verify the bypass damper is open. Note, the damper may not
fully open.
d)
If the open zones are not noisy, the bypass damper is set.
BYPASS DAMPERS – BAROMETRIC
AIRFLOW
AIRFLOW
RETURN
BAROMETRIC
BYPASS
HORIZONTAL APPLICATION
SHEET METAL
PIPE
SUPPLY
PLENUM
A/C UNIT
OR
FURNACE
A/C UNIT
OR
FURNACE
RETURN
AIR
PLATFORM
BAROMETRIC
BYPASS
RETURN AIR GRILLE
AIRFLOW
SUPPLY
PLENUM
VERTICAL APPLICATION
ROOF TOP INSTALLATION
Down Discharge Application
A/C UNIT
OR
FURNACE
BAROMETRIC
BYPASS
AIRFLOW
SHEET METAL
PIPE
RETURN
PLENUM
SUPPLY
PLENUM
ROOF LINE
OPEN RETURN PLENUM BYPASS APPLICATION
RETURN AIR
GRILLE
AIR CONDITIONING
UNIT
SUPPLY
DUCT
BYPASS DAMPER
To prevent bypass air from
flowing out the return grill,
use a short open ended
return air plenum to
connect the bypass
damper to the unit.
