Installation Instructions; Choosing A Location; Dispersion Tube - Aprilaire 800 Installation & Maintenance Instructions Manual

InSTallaTIon InSTRUCTIonS

CHooSInG a loCaTIon

DISPeRSIon TUbe

When choosing a location for the dispersion tube three things must be considered: Location in duct, elevation with respect to the humidifier, and
distance from humidifier to dispersion tube .
Duct location
The preferred location for the dispersion tube is in a supply duct because higher temperature air will more readily absorb the moisture . Whether
installed in a supply or return, the dispersion tube must be in a straight section of duct to avoid turbulent air and must be far enough upstream
of any obstruction or bends in the duct to allow the steam to be fully absorbed to prevent condensation . The exact distance from obstructions in
the duct depends on air temperature, RH set point, and airflow velocity in the duct . Table 2 provides absorption distance for typical conditions .
The higher the RH setting, the longer the absorption distance . Warmer air shortens the absorption distance . If absorption distance is a concern,
install dispersion tube in supply duct and configure humidifier and control to operate only during HVAC system heat call . Call Aprilaire Tech
Support at 1-800-334-6011 for additional information on absorption .
The dispersion tube must be mounted on a vertical surface with the tube angled up .
If the dispersion tube is mounted on insulated ductwork, make sure insulation is not more than 2" thick at tube location to prevent insulation
from blocking first steam outlet .
Table 2 – absorption Distance (Minimum distance from dispersion tube downstream to any obstruction or bend in duct)
Input Humidifier
Power output
120 V 11 .5 gal/day
208 V 20 .5 gal/day
240 V 23 .3 gal/day
70°f & 30% RH
airflow Velocity
300 fpm
600 fpm
1200 fpm
1800 fpm
300 fpm
600 fpm
1200 fpm
1800 fpm
300 fpm
600 fpm
1200 fpm
1800 fpm
70°f & 45% RH
Setpoint
Setpoint
7" 11"
3" 6"
2" 3"
< 2" 2"
13" 19"
6" 10"
3" 5"
2" 3"
15" 23"
6" 12"
5" 6"
3" 4"
65°f & 45% RH
Setpoint
13"
7"
3"
2"
23"
12"
6"
4"
28"
13"
7"
5"
5