Nortel North American DMS-100 Instruction Manual page 87

Repairing and replacing NT3X90AB cooling units
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DMS-100 Family NA100 Trouble Locating and Clearing Procedures Volume 2 of 2 LET0015 and up
Trouble locating and clearing procedures (continued)
If the fan
does not work correctly, and did
not work in step 17
To turn OFF the inverters, use the toggle switches at the back right corner of
the inverters.
Disconnect the wiring to the sensor switch from the fan that has faults. Note
the position and color of the wires.
Note the position of the air flow switch on the fan (or fans) that has faults.
Remove the sensor switch from the switch bracket. Lay the switch to one
side.
Cut the two tie wraps that secure the power cord to the fan.
Remove the four screws, spacers, nuts, and washers that secure the fan to
the cooling unit.
Disconnect the power cord at the fan terminals.
Remove the fan.
Plug a new fan into the power cord.
Mount the new fan. Install the fan so that air flows toward the top, as indicated
on the label. Secure the fan with screws, spacers, nuts, and washers.
Use new tie wraps to secure the power cord to the fan.
Reconnect the wiring to the sensor switch, as noted in step 35.
Attach the sensor switch to the switch bracket. Secure the switch in position
with screws, nuts, and washers.
To switch ON the inverters, use the toggle switches at the back right corner
of the inverters.
Inspect the fan operation.
If the fan
works correctly, but did not
work in step 17
did not work correctly, and did
not work in step 17
Inspect the sails of the air flow sensors. Replace or repair any that appear to
have faults.
Do
step 34
Do
step 55
step 78
1-71
(continued)