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

INSTALLATION INSTRUCTIONS

Each humidifier requires its own steam hose and dispersion tube. Do not connect steam hoses from more than one humidifier together. Back-
pressure from one humidifier can lower the water level in the canister in the other humidifier and cause operational problems.
Do not install the dispersion tube in a duct with greater than 2 in. wg static pressure. High duct pressure can cause back-pressure in the canister
which can result in unstable unit operation.
Do not mount humidifier in a location where operating ambient temperatures exceed 140°F or where freezing temperatures may occur.

CHOOSING A LOCATION

DISPERSION TUBE LOCATION

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 and Absorption Distance
Absorption distance, the unobstructed straight line distance needed for steam to be fully absorbed, is dependent on air velocity, air temperature and
relative humidity in the duct . Determine absorption distance based on the lowest duct temperature, lowest air velocity and highest humidity that
the system will see. The dispersion tube must be located in a straight section of duct far enough upstream of any obstructions or bends in the duct .
Use TABLE 3 to determine the appropriate absorption distance .
Operation during AC calls is not recommended because of the potential for condensation in the ductwork . Configure controls to lock out the
humidifier during AC calls and use the blower activation feature on the ADHC to allow the humidifier to run with the blower only . Call Aprilaire Tech
Support at 1-800-334-6011 for additional information on steam absorption .
The dispersion tube must be mounted with the plate on a vertical surface with the tube angled up as shown in FIGURE 4 . The steam tubelets must
face up regardless of the airflow direction in the duct . The plate is labeled "UP" to indicate proper orientation . On horizontal duct runs install the
dispersion tube low in the duct, on vertical runs center the tube on the duct .
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 .
NOTE: If dispersion tubes for two humidifiers are installed in one duct, double the dispersion distances . If three dispersion tubes are installed, triple
the dispersion distance . Position dispersion tubes so one does not discharge directly onto another .
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CAUTION