45
System Pre-Start Procedures (Continued)
23. Reconnect the economizer leads R, B, W, & Y to the ap-
propriate terminals on the controller.
24. Turn the control circuit switch 1S2, in the unit control
panel, and the main power disconnect switch to the
“OFF” position.
25. Remove the jumper, installed in step 5, from terminals 6
& 7.
26. Remove the 3,400 ohm resistor from terminals T & T1
and reconnect the discharge air sensor leads to termi-
nals T & T1.
27. Remove the “Test Plug” from the W7100 test socket and
reinstall the red dust cover.
28. Reconnect the field installed evaporator fan auxillary in-
terlock wire to terminal board 7TB5 terminal 3.
29. Turn all control switches to the “On” position and restore
main power to the system.
Figure 4-3
W7100A Discharge Air Controller
Discharge Air Sensor Checkout
(Honeywell Sensor)
1. Verify that the main power disconnect switch and the
control circuit switch 1S2, in the unit control panel, is
“OFF”.
2. At the Discharge Air Controller, in the unit control panel,
disconnect the wire connected to Terminal T1. Use a
digital ohmmeter to measure the resistance across Ter-
minal T and the wire removed from Terminal T1.
3. Use the conversion chart in Table 4-1 to convert the mea-
sured resistance to an equivalent temperature.
4. Measure the actual temperature at the sensor location. If
the measured resistance in step 2 is not within ± 10.0
ohms of the actual temperature, the sensor is out of
range; replace it.
Note: Before condemning the sensor, verify that
the connecting cable resistance is not excessive.
Refer to the “Field Installed Control Wiring”
section.
5. Make all necessary repairs and reconnect the duct sen-
sor lead to terminal T1 on the controller.
6. Turn all control switches to the “ON” position and restore
power to the system.
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