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Installation Tips
Condensate Return Line
Condensate from the header or tubes cannot be elevated. Do not connect steam traps to
pressurized condensate return lines. If gravity drain is not possible please use a condensate
pump rated for 212°F water or PURE Humidifier Company Part No. 16033 Hartell A3X-115
condensate pump.
Laminar air flow
Tube assembly must be installed in a location that allows for laminar air flow across entire
grid. A minimum velocity of 300 feet per minute is required to avoid saturation and excessive
fog travel.
Plug fan installations
Install tube assembly as close as possible to the upstream coil to ensure laminar airflow and
proper absorption.
Insulated ducts
Internally insulated ducts must be lined with a non-absorbent material to avoid saturation. If
the duct is lined it must be removed three feet (3’) upstream and ten feet (10’) downstream of
tube assembly.
Final Filters
Tube assembly must be installed a minimum of ten feet (10’) upstream of final filters.
VAV Systems
Low velocity will cause long fog trails and steam will rise wetting the top of the AHU/duct
casing. Modulating VAV high-limit humidistat is required. A minimum velocity of 300 feet per
minute is required to avoid saturation and excessive fog travel.
Controls
Fan Interlock Switch
PURE Humidifier Co. recommends the use of an air flow proving switch or fan interlock to
prove air flow prior to humidifier cooperation. Humidifier operation without air flow will result
in over-saturation of the air stream. Air flow proving switches are available as optional
equipment from your PURE Humidifier Co. representative.
High-Limit Humidistat
PURE Humidifier Co. recommends the use of a duct high-limit humidistat to prevent
humidifier operation when the duct humidity level exceeds 85% relative humidity. Humidifier
operation above 85% relative humidity can result in over-saturation of the air stream. High-
limit humidistats are available as optional equipment from your PURE Humidifier Co.
representative. The high limit humidistat should be 12 to 14 feet (365-427 cm) downstream
from the humidifier injection tube.
Smoke Alarms and Temperature Sensors
Smoke alarms should be located 12 to 14 feet (365-427 cm) upstream from the humidifier
injection tube.
Temperature sensors should be located 12 to 14 feet (365-427 cm) downstream from the
humidifier injection tube, or past any visible fog travel that may be greater than this distance
.
