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JOHNSON CONTROLS
25
SECTION 2 - START-UP AND OPERATION
FORM 102.20-OM2
ISSUE DATE: 6/01/2015
2
Ductwork Inlet Requirements
When connecting the ductwork to a mixing box with
an AMS-60 damper, a minimum of one (1) equivalent
duct diameter of straight duct is required before enter-
ing the AMS-60 damper.
1 equivalent duct diameter = d
D
W
H
Mixing Box
FIGURE 14 -
DUCTWORK INLET REQUIREMENTS
LD17215
If one equivalent duct diameter cannot be achieved
during installation, the rectangular elbow may be sub-
stituted with a radius elbow. The outside radius must
have a R/W ratio of 0.75 or more.
Mixing Box
R
W
FIGURE 15 -
DUCTWORK RADIUS
LD17243
Damper Linkage Arrangements
The AMS-60 mixing box will ship with independent
return air and outside air damper actuators if selected
in the MB or FM segments.
Louver/Damper Combination
Outdoor AHU economizer and mixing box sections
will utilize an integral rain resistant, airflow sensing
louver/damper combination with operation and set-up
similar to the AMS-60. The indoor and outdoor AHU
designs have the same possible damper configurations.
Damper Configurations
There are 3 possible damper configurations, 25% Sens-
ing option (Min./Max.), 25%/75% Sensing option, and
100% Sensing option.
•
25% Sensing Option (Min./Max.)
FIGURE 16 -
25% SENSING OPTION
LD17244
The 25% Sensing (Min./Max.) option arrangement is a
dual damper design and used for measuring the mini-
mum outside air requirement. In this arrangement, the
25% damper would be for monitoring airflow through
the first 25% down to 3.75% nominal flow and the
75% damper would have a separate actuator and used
for economizer control only.
This option would be the best low cost option for areas
in which economizer cycles are not often seen, such as
the southeast, and are required to constantly operate in
at the minimum outside air position.
•
25/75% Sensing Option
FIGURE 17 -
25%/75% SENSING OPTION
LD17245