13
INSTALLER’S GUIDE
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
Table 1. Motor Operation Checkout - W7459 Control Only
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 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
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 en-
thalpy sensor) reconnect 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 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
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 back
-
ward.
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).
Multimeter indication is between 3 and 25 mA if sensor is
operating properly.
If multimeter indicates zero, the sensor may be wired back
-
ward.
