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Checkout Procedure
1. Disconnect power at TR and TR1.
A
2. Disconnect jumper P to P1.
3. Jumper TR to 1.
4. Jumper T1 to T.
5. If connected, remove C7400 Solid State Enthalpy Sensor from ter-
minals S0 and +. Ensure factory-installed 620 ohm resistor is connect-
ed to terminals Sr and +.
6. Apply power (24Vac) to terminals TR and TR1
1. Disconnect factory-installed 620 ohm resistor from terminals Sr and
B
+
1. To simulate high and low enthalpy (single enthalpy sensor) re-
C
connect factory-installed 620 ohm resistor from terminals Sr and +.
Connect 1.2K ohm 4074EJM Checkout Resistor across terminals So
and +.
2. Turn enthalpy setpoint potentiometer to "A".
3. Turn enthalpy setpoint potentiometer to "D".
4. Disconnect the 1.2K ohm checkout resistor
1. To verify sensor operation, reconnect the + lead of the outdoor
D
enthalpy sensor to the + terminal of W7459.
2. Connect a DC multimeter between terminal So of the W7459A and
terminal S of the enthalpy sensor. See Fig. 11 (positive meter lead to
terminal S of the enthalpy sensor).
3. When using differential enthalpy, check the return air enthalpy
sensor by connecting a DC multimeter between terminal Sr of the
W7459A and terminal S of the return air enthalpy sensor. (positive
meter lead to terminal S of the enthalpy sensor).
Location of Enthalpy Set Point,
Minimum Position and LED
1
MINIMUM DAMPER POSITION ADJUSTMENT
IS PRESENT ONLY ON W7459A,D MODELS.
Table 2. Enthalpy Checkout Procedure - W7459 Control
ENTHALPY
CHANGEOVER
SETPOINT
MINIMUM
DAMPER
POSITION
1
SETTING
LED LIGHTS
WHEN OUTDOOR
AIR IS SUITABLE
FOR FREE COOLING
M9098B
Figure 11. Enthalpy LEDs and Checkout
INSTALLER'S GUIDE
Response
LED is off.
Motor is in closed position.
LED turns on, motor drives toward open.
LED turns on, indicating low enthalpy.
Motor drives toward open.
LED turns off, indicating high enthalpy.
Motor drives toward closed.
Multimeter indication is between 3 and 25 mA if
sensor is operating properly.
If multimeter indicates zero, the sensor may be
wired backward.
Multimeter indication is between 3 and 25 mA if
sensor is operating properly.
If multimeter indicates zero, the sensor may be
wired backward.
Meter Location for Checkout
and Troubleshooting
W7459
TR1
TR
B
C
+
S O
D
A
S R
+
INSERT DC MILLIAMMETER BETWEEN S O AND S FOR CHECKOUT
MULTIMETER
1
AND TROUBLESHOOTING.
2
JUMPER USED FOR SINGLE ENTHALPY CONTROL.
ENTHALPY CHANGEOVER
SETPOINT
+
1
S
+
C7400
2
DC
620 OHM
MULTIMETER
MILLIMETER
JUMPER
LED LIGHTS WHEN
OUTDOOR AIR IS SUITABLE
FOR FREE COOLING
M9097
11
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