PN 475573
Vari-Green
®
Control
Indoor Air Quality–Temp/Humidity
1
Installation, Operation and Maintenance Manual
Please read and save these instructions for future reference. Read carefully before attempting to assemble,
install, operate or maintain the product described. Protect yourself and others by observing all safety
information. Failure to comply with instructions could result in personal injury and/or property damage!
The Temperature and Humidity Controller is
specifically designed to control a Vari-Green fan
motor. The Temperature and Humidity Controller
will sense the temperature and humidity in the
space and will automatically adjust the speed of
a supply or exhaust fan to adjust the ventilation
rate accordingly. The temperature measurement
will be compared to a field adjustable temperature
setpoint, processed through a Proportional/Integral/
Derivative (PID) control algorithm to produce a 2
to 10 VDC fan motor control output. The humidity
measurement will be compared to a field adjustable
humidity setpoint, processed through a PID control
algorithm to produce a 2 to 10 VDC fan motor
control output. If the unit is in temperature only
mode the temperature algorithm’s output shall be
used to provide the fan motor control output. When
the unit is in humidity-only mode the humidity
algorithm’s output shall be used to provide the
fan motor control output. When the unit is in
temperature and humidity mode the algorithm with
the greatest output shall be used to provide the fan
motor control output.
When all active algorithms are satisfied, the output
voltage shall be set to its lowest value, 2 VDC. If
the temperature is 1°F below the temperature
DANGER
Always disconnect, lock and tag power source before
installing or servicing. Failure to disconnect power
source can result in fire, shock or serious injury.
CAUTION
When servicing the fan, motor may be hot enough
to cause pain or injury. Allow motor to cool before
servicing.
CAUTION
Precaution should be taken in explosive
atmospheres.
Only qualified personnel should install this product.
Personnel should have a clear understanding of
these instructions and should be aware of general
safety precautions. Improper installation can result
in electric shock, possible injury due to coming in
contact with moving parts, as well as other potential
hazards. Other considerations may be required
if high winds or seismic activity are present. If
more information is needed, contact a licensed
professional engineer before moving forward.
Temperature and Humidity Controller
General Safety Information
setpoint in
temperature control
and the humidity
is 3% below the
humidity setpoint in
humidity control or
both in temperature
and humidity control,
the voltage output
may be set to zero
(optional cutout
mode). The unit
will resume normal
fan operation if
the temperature
changes by 1°F or
the humidity changes by 5%.
Ventilating based on the temperature and humidity
measurements assures that the space will not be
over or under ventilated while using the Vari-Green
motor technology to operate quietly and efficiently.
The Temperature and Humidity Controller has
adjustments for setpoint, minimum and maximum
fan speed. The fan speed and temperature or
humidity level are available as an analog output to
be read by a building
