DriSteem Vapor-logic3, Installation And Operation Manual

Page: 26 / 84

22
Figure 22-1: Temperature compensation
transmitter placement
Temperature compensation offset option
This option is identified as a “T” in the second-from-
last place of your program code nomenclature (for
example: EV11400285A7O
T
X).
When selected as an option, DRI-STEEM provides a
temperature compensation (temp comp) transmitter. The
temperature compensation transmitter continually
monitors the interior window glass temperature and
transmits this temperature to VAPOR-LOGIC
®
3
.
VAPOR-LOGIC
3
then compares the glass temperature
to the desired RH set point in the humidified area and
calculates the dew point (°C) for the space.
VAPOR-LOGIC
3
will lower (offset) the desired RH set
point so that moisture does not form on windows. The
keypad/display will show the amount of offset that has
taken place as a modified set point. As the interior
window glass temperature increases, VAPOR-LOGIC
3
will reduce the offset and restore system control to the
normal RH set point for the space.
The transmitter provided with VAPOR-LOGIC
3
is
calibrated for -29°C to 71°C with output from 4-20 mA.
For example, a temperature reading of 21°C should
produce a measurement of 12 mA.
Installation:
Temperature compensation transmitter
Installation
Temperature compensation transmitter.
Install using an 1 mm
2
plenum-rated shielded cable for
transmitter wiring with grounding shield at the shield
ground lug in the control cabinet (see Figure 21-1 on
the previous page).
Temperature compensation
transmitter placement
See Figure 22-1 below.
1. Position the temperature compensation transmitter
control box on a wall adjacent to a window frame
facing north or northeast.
2. Place flat surface of temperature sensor tip on
lower corner of glass surface.
3. Temporarily hold the sensor tip in place with strips
of masking tape.
4. Apply a small amount of clear RTV silicone
adhesive over and around the sensor tip (making
sure the sensor tip is in contact with the window
glass).
5. After adhesive has cured, remove masking tape.
OM-337
Double
pane
window
glass
Secure temperature
sensor tip to inside
surface of window glass
using clear RTV silicone
adhesive
Typical
sensor
cord routing
Surface-mounted
thermostat
temperature
control
box on wall
Thermostat
control wires
Window
framing
VL3-IOM-0301-METRIC.pdf 26 11/19/2009 9:22:38 AM