KAH Operation & Maintenance Guide
Page: 13 of 88
Krueger | 1401 N Plano Rd | Richardson, TX 75081 | 972.680.9136 | [email protected] | www.krueger-hvac.com
SECTION 2 - START-UP & OPERATION (CONTINUED)
Damper Configurations
There are 3 possible damper configurations, 25% Sensing
option (Min./Max.), 25% / 75% Sensing option, and 100%
Sensing option.
25% Sensing Option (Min./Max.)
The 25% Sensing (Min./Max.) option arrangement is a
dual damper design and used for measuring the minimum
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
The 25 / 75% Sensing option arrangement is similar to the
25% Sensing (Min./Max.) option, but also allows you to
measure airflow throughout the economizer cycle. In this
arrangement, the 25% damper would be for monitoring
nominal airflow through the first 25% down to 3.75% and
the 75% damper would be for monitoring the remaining
75%.
100% Sensing Option
The 100% sensing arrangement is a single damper design
used to measure airflow throughout the full range of the
outside air damper down to 15% of nominal airflow.
The 100% sensing option is the lowest cost option, but
should not be utilized when minimum airflow to be sensed
falls below 15% nominal flow. The 25% Sensing (Min./
Max.) and 100% Sensing option arrangements will be the
most prevalent.
The 100% Sensing arrangement with the outside and
return air dampers tied to a common actuator, will usually
be the most common configuration and cost-effective
solution. However, areas in which economizer cycles
are not often seen and operate primarily in minimum
outside air position, the 25% Sensing option should be the
preferred option for lowest airflow monitoring and a cost-
effective solution.
In each of the available configurations, the minimum
airflow across the sensing portion of the airflow monitoring
station is 300 FPM for the KAH unit.
FIGURE 10 - 25% SENSING OPTION
FIGURE 11 - 25% / 75% SENSING OPTION
FIGURE 12 - 25% / 75% SENSING OPTION