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INSTALLER’S GUIDE
Table 2. Enthalpy Checkout Procedure - W7459 Control
Checkout Procedure Response
A 1. Disconnect power at TR and TR1.
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
LED is off.
Motor is in closed position.
B 1. Disconnect factory-installed 620 ohm resistor from terminals Sr and
+
LED turns on, motor drives toward open.
C 1. To simulate high and low enthalpy (single enthalpy sensor) re-
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".
LED turns on, indicating low enthalpy.
Motor drives toward open.
3. Turn enthalpy setpoint potentiometer to "D".
LED turns off, indicating high enthalpy.
Motor drives toward closed.
4. Disconnect the 1.2K ohm checkout resistor
―
D 1. To verify sensor operation, reconnect the + lead of the outdoor
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. 17 (positive meter lead to
terminal S of the enthalpy sensor).
Multimeter indication is between 3 and 25 mA if
sensor is operating properly.
If multimeter indicates zero, the sensor may be
wired backward.
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).
Multimeter indication is between 3 and 25 mA if
sensor is operating properly.
If multimeter indicates zero, the sensor may be
wired backward.
Table 1. Motor Operation Checkout - W7459 Control Only
MODEL DRIVE MOTOR OPEN DRIVE MOTOR CLOSED SPRING RETURN
M7415 Power to TR and TR1, jumper T and T1
Disconnect jumper at T or T1 and
disconnect P or P1, if connected
Disconnect power at TR and TR1
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