Aprilaire 1150 Humidifier User Manual


 
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CHOOSING A DISTRIBUTION TUBE LOCATION
When installing a steam humidifier on a packaged rooftop unit application, there are two locations that can be
used to mount the steam distribution tube: supply plenum/duct (Location A) or the return plenum/duct (Location B).
Note: Wherever distribution tube is installed, there must be a minimum of 4.5” between top of tube and the duct
ceiling. Refer to Figures 12 and 13 on page 17.
Location A is the best choice because
:
The distribution tube is humidifying 100% of the air
The supply air temperature is typically higher than the return air temperature, allowing for better absorption
of the steam
Note: In applications using zone control products, the distribution tube must be installed upstream of all zone
control dampers to ensure that all zones receive humidified supply air
Choosing control device locations
Install the high humidity limit switch (a recommended optional device) a minimum of 5’ (1.5 m) downstream
of the distribution tube.
Install the Automatic Steam Humidifier Control in the return air duct a minimum of 6” upstream of the
distribution tube.
Install the airflow proving switch in the supply air plenum.
OM-4043
FIGURE 11 – Placing a Distribution Assembly in a Rooftop Air Handler Application
15