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MODEL
DRIVE MOTOR OPEN
M7415
Power to TR and TR1, jumper T and T1
Table 2. Enthalpy Checkout Procedure - W7459 Control
Checkout Procedure
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 En-
thalpy Sensor from terminals S0 and +. Ensure
factory-installed 620 ohm resistor is connected
to terminals Sr and +.
6. Apply power (24Vac) to terminals TR and TR1
B
1. Disconnect factory-installed 620 ohm resistor
from terminals Sr and +
1. To simulate high and low enthalpy (single en-
thalpy sensor) reconnect factory-installed 620 ohm
resistor from terminals Sr and +.Connect 1.2K ohm
4074EJM Checkout Resistor across terminals So
and +.
C
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 outdoorenthalpy sensor to the + terminal of
W7459.
2. Connect a DC multimeter between terminal So
of the W7459A and terminal S of the enthalpy sen-
sor. See Fig. 17 (positive meter lead toterminal S
D
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.
(positivemeter lead to terminal S of the enthalpy
sensor).
Table 1. Motor Operation Checkout - W7459 Control Only
Disconnect jumper at T or T1 and
disconnect P or P1, if connected
DRIVE MOTOR CLOSED
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 back-
ward.
Multimeter indication is between 3 and 25 mA if sensor is
operating properly.
If multimeter indicates zero, the sensor may be wired back-
ward.
INSTALLER'S GUIDE
SPRING RETURN
Disconnect power at TR and
TR1
Response
13
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