ADC PCS-822, Technical Practice, Page: 30 / 46

SCP-PCS822-021-03H January 6, 2003
20
ADC Telecommunications, Inc.
PFU-830 F
AN
U
NIT
The PFU-830 fan unit provides two fans for cooling the Field Shelf ( Figure 20 ). It contains Fan Alarm and Door
Alarm circuits to report a fan failure or a open door condition to the Management Unit. The PFU-830 has an
on-board thermal sensor to measure temperature and operates the fans as needed. A manual fan test may be
initiated by pressing the “FAN TEST” switch for at least four seconds. The fan low rpm alarm circuit is disabled for
the first few seconds after test activation to allow the fans to attain operating speed, avoiding a false low rpm alarm.
If the fan fail LED remains off after holding the fan test button down for four seconds or more, then the fan unit has
passed the fan test. If there is a fan failure, the fan fail LED is lit continuously, indicating that the PFU-830 fan unit
should be replaced.
The PFU-830 provides secondary protection for the following signals ( Figure 11 on page 11 ):
• Door Alarm Output
• Critical Alarm Output
• Major Alarm Output
• Minor Alarm Output
• Fan Alarm Output
• External Miscellaneous Alarm Input
• External Miscellaneous Alarm Output
• AC Power Alarm Input
• AC Power Alarm Output
Figure 20. PFU-830 Fan Unit
The PFU-830 fan unit must be installed for the Field Shelf alarms to be activated and to ensure proper
cooling. Subscriber services are not interrupted while the fan unit is being replaced.
Fan Test
Fan Fail
Switch
LED