Temp-Vents - Humidistats For
Description: A humidistat can connect to the Power
Temp-Vents to turn the fan on and off automatically. Two types
of humidistats are available.
Model B: Damp weather humidistat, mounts behind an intake
vent, opposite the side where the power vent is mounted. Power vents
stay off when the humidity is above the setting. The vent turns on
when humidity is below the setting or if there is a quick rise in
humidity, so that the unit turns off when it is raining.
Model C: Turns unit on when humidity in crawl space rises
above a pre set limit, usually set at 50% humidity.
The difference between the 2 controllers is the conditions that
they shut off. The Humidistat B - HUB (damp weather shut off) is recommended to be
set at 75% Relative Humidity. The operation of it will cause it to shut down at any
Relative Humidity above the set point. The Humidistat C - HUC is the opposite, it will turn on at
any condition above the set point. Operation is such that the 2
controllers when plugged together in series will maintain the
humidity in the crawl space between the set points on the
For example, the Humidistat B - HUB set at 75% and the Humidistat
C - HUC set at 40% will run
at anytime the crawl space has a humidity below 75% and above 40%.
If the humidity drops below 40% the Humidistat C - HUC will shut off and the fan
will no longer run. If the humidity in the space goes above 75% the
Humidistat B - HUB will shut off and the fan will no longer run. The
Humidistat B - HUB is
intended to be placed in the air stream of the incoming outside air,
therefore, if it is raining or humid out and the fan comes on and
starts bringing in air above the Humidistat B - HUB set point (75%), the
Humidistat B - HUB will
turn off and the fan will stop.
The obvious down side to this is that if the crawl space rises
above the set point of the Humidistat B - HUB , the fan will not turn on. However,
without the Humidistat B - HUB , the Humidistat C - HUC would turn on at anytime the crawlspace was
above its set point and run the fan, it could very well bring in more
humid air than is already in the crawlspace, such as when it was
|The Humidistat / Thermostat system can be used to control up to 6
power vents at one time.