Alarms
8.0ALARMS
The microprocessor control system will audibly and visually signal all ENABLED Alarms (including two (2) custom alarms). These special alarms can be chosen from the optional alarm list and/or can have their own fully custom text. The custom alarm inputs are contact closures wired from terminal
When a new alarm occurs, it is displayed on the screen and the audible alarm is activated. (If communicating with a Liebert Site Product, the alarm is also transmitted.) The message “PRESS ALARM SILENCE” will prompt the operator to silence the alarm. After the alarm is silenced, the display will return to the Normal Status Display. Alarms can be reviewed by selecting the “ACTIVE ALARMS” feature. The alarms can also be silenced through communications with a Liebert Site Product unit.
Many alarms will reset automatically when the alarm condition is no longer represented and only after it has been acknowledged by being “Silenced.” The exceptions are:
1.software alarms, i.e., Loss of Power and Short Cycle alarms will reset automatically 30 seconds after being silenced or acknowledged
2.specific alarms monitoring overload or high pressure switches may require a manual reset depending upon the model
8.1Alarms: Definitions and Troubleshooting
The following list provides a definition and troubleshooting suggestions for each type of alarm. Refer to 11.0 - Troubleshooting for additional details. If you need further assistance, contact your Liebert supplier. THE CUSTOMER MUST SPECIFY ALARM(S) AT THE TIME OF ORDER. OTHER DEVICES AND WIRING MAY BE REQUIRED AT THE FACTORY FOR SOME OF THE ALARMS.
8.1.1Custom Alarms
Custom alarm(s) messages are programmed at the LCD display. The message displayed may be included in a list of provided alarms or it may be customized text (for up to 2 alarms). IF CUSTOMIZED TEXT IS USED, MAINTENANCE PERSONNEL SHOULD BE INFORMED OF THE ALARM FUNCTION AND THE REQUIRED ACTION.
8.1.2High Head Pressure
Compressor head pressure is monitored with a
If head pressure exceeds 400 psig (2785 kPa), the switch opens the compressor contactor and sends an input signal to the control. The high head pressure condition is acknowledged by pressing the Alarm Silence button on the wall box, which will clear the alarm if the high head pressure condition no longer exists. If the compressor is Off for 1 hour, the control goes into a special cold start mode. In the cold start mode on a call for cooling or dehumidification, the liquid line solenoid valve (LLSV) is energized. If the high pressure switch does NOT trip within 10 seconds, the control returns to normal operation of monitoring the high head pressure switch for three occurrences in a 12 hour period. It is a rolling timer, and after the third high head alarm occurs and is acknowledged by the user, it will lock Off the compressor.
If while in the cold start mode, the high head pressure switch DOES trip within 10 seconds of the activation of the LLSV, the control does not annunciate the alarm. The control will turn Off the LLSV and delay 10 seconds. The control will permit this occurrence two more times or a total of three times. If on the fourth try, the high head pressure switch trips within 10 seconds, the control will annunciate the alarm, turn Off the LLSV, wait for the user to acknowledge the alarm and hold the compressor Off for 3 minutes, the length of the normal short cycle control. The control will permit this occurrence three times. On the third occurrence, the control will lock the compressor Off until the control power is reset.
Liebert® | 52 |
