Titus Mixing Box Controls IOM - Manual (Page 6)

Mixing Box Control Installation Manual
IOM-MBC-00 08-30-04
6 of 15
Figure 8. Solid-State Enthalpy Sensor
Table 6. Operating Ratings
Specific Description
Case
Duct-mounted
Temperature Sensing
Element:
Thermistor
Output Signal 4 to 20 mA current signal;
increases from 4 to 20 mA as
enthalpy decreases
Operating ambient
temperature
-40 to 125° Fahrenheit (-40 to
+52° Celsius)
Shipping temperature
rating:
-40 to 150° Fahrenheit (-40 to
+66° Celsius)
Maximum power
consumption
0.45 Vac
Maximum supply
voltage
18 to 24 Vdc
Electrical connection Two ¼-inch quick-connect
terminals
Listed by Underwriters Laboratories Inc.
Location and Mounting
The sensor mounts in any position up to 200 feet (61
meters) away from the logic module – W7459C and may
be used for the following operational circumstances.
•
Proportional damper control: Attach the logic
module to the Damper Motor’s side.
• Outdoor air sensing: Mount in any orientation where
it is exposed to freely circulating air, but is protected
from rain, snow, and direct sunlight.
• Return air sensing: For differential enthalpy control,
a second C7400A enthalpy sensor can be connected
to the W7459 and mounted in the return air duct.
Note: Contact your Titus representative if
specifications call for differential enthalpy control.
Verification and Troubleshooting
The following table provides the actions and responses to
verify the installation of W7459C logic module installed on
an M8405 Actuator.
DANGER
DISCONNECT POWER SUPPLY BEFORE
CONNECTING WIRING TO PREVENT ELECTRICAL
SHOCK OR EQUIPMENT DAMAGE
Caution: Exercise care when adjusting the
enthalpy changeover and minimum damper
position control. Use a small screwdriver for
these adjustments. Excessive force may damage
the controls.
Perform verification and troubleshooting steps in
order.
Table 7. Three-Position Control Verification
and Troubleshooting
e s n o p s e R n o it c A
A.
Power
1. Disconnect power at
terminals TR and TR1.
2. Disconnect wires from
terminals 6, X and D.
3. Jumper TR and 1.
4. Jumper 6 and D.
5. If connected, remove
C7400A enthalpy sensor
from terminals S
O
and +.
Factory-installed 620-ohm
resistor should be
connected to S
R
and +.
6. Apply 24 Vac power to
terminals TR and TR1.
LED should be off.
Motor is in closed
position.
7. Disconnect factory-
installed 620-ohm resistor
from terminals S
R
and +.
LED should be on.
Motor drives toward
open.
B. Enthalpy Simulation
1. To simulate high and low
enthalpy (single enthalpy
sensor)).
2. Reconnect factory-
installed 620-ohm resistor
across terminals S
R
and +.
3. Connect 1.2k ohm
checkout resistor across
terminals S
O
and +.