Specifications
DRI-STEEM
®
Installation Guide: Humidistat or sensor placement 1 of 1
Installation Guide
Humidistat or sensor placement
IMPORTANT
In most cases, we recommend that you do not interchange duct and room humidity devices. Room humidity
devices are calibrated with zero or little airflow; whereas, duct humidity devices require air passing across them.
Recommended sensor locations
A This is the ideal sensing location because this placement ensures the best uniform mix of dry and moist air
with stable temperature control.
A' This location is acceptable, but the room environment can affect controllability, such as when the sensor is
too close to air grilles, registers, or heat radiation from room lighting.
B This location is acceptable because it provides a good uniform mixture of dry and moist air, but if an ex-
tended time lag exists between moisture generation and sensing, make sure the control contractor extends
the sampling time.
B' This location behind a wall or partition is acceptable for sampling the entire room if the sensor is near an air
exhaust return outlet. This location is also typical of sensor placement for sampling a critical area.
C These locations are not acceptable because they may not represent actual overall conditions in the space.
D These locations are not acceptable. Do not place sensors near windows, door passageways, or areas of
stagnant airflow.
E This is the best location for a duct high limit humidistat or humidity sensor.
Outside air
Relief air
Damper control
Return air
AHU
(air handling unit)
Window
Point of vapor absorption
8' to 12'
(2.4 to 3.7 m)
minimum
High limit humidistat or high limit
transmitter (set at 90% RH
maximum) for VAV applications
Airflow switch (sail type
recommended for VAV
applications)
A'
Humidifier dispersion unit
Turning vanes
% RH offset option: Place a temperature
compensation transmitter on lower corner of the
inside surface of double-pane window glass on
north or northeast facing window
Wall
E
C
B
Doorway
DC-1084
Damper control
Window
Vapor absorption has
taken place
B'
C
D
A
D
D