Liebert 8 Tons, 50 & 60Hz user manual Setpoints, Status, Active Alarms, Alarm History

Microprocessor Control

3.3Setpoints

Setpoints and system setup parameters are kept in nonvolatile memory. Selecting SETPOINTS from the Main Menu will display the following selections:

•TEMPERATURE SETPOINT

•TEMPERATURE SENSITIVITY

•HUMIDITY SETPOINT

•HUMIDITY SENSITIVITY

•HIGH TEMPERATURE ALARM

•LOW TEMPERATURE ALARM

•HIGH HUMIDITY ALARM

•LOW HUMIDITY ALARM

Scroll through this sub-menu by using the UP/DOWN arrow, then press ENTER to select a particu- lar function. To change a value, press ENTER and use the UP/DOWN arrows. When the value has been changed, press ENTER to store the value. For example, to change the temperature setpoint from the main status display:

1.Press MENU key to display main menu.

2.Scroll to “SETPOINTS” using the UP/DOWN arrow key. Press ENTER.

3.Scroll to “TEMP SETPT” using the UP/DOWN arrow key. Press ENTER.

4.Use the UP/DOWN arrow to change the value. Press ENTER.

Table 10 Default setpoints and allowable ranges

Setpoint	Default	Range
Temperature Setpoint	72°F	40-90°F (5-32°C)
Temperature Sensitivity	2.0°F	1-9.9°F (0.6-5.6°C)
Humidity Setpoint	50%	20-80% RH
Humidity Sensitivity	5%	1-30% RH
High Temperature Alarm	80°F	35-95°F
		(2-35°C)
Low Temperature Alarm	65°F	35-95°F
		(2-35°C)
High Humidity Alarm	60%	15-85% RH
Low Humidity Alarm	40%	15-85% RH

3.4Status

The operator can monitor the percentage heating, cooling, dehumidifying, and humidifying status of the unit by selecting “STATUS” from the main menu.

3.5Active Alarms

The operator can monitor the alarms status by selecting “ACTIVE ALARMS” which will display a “Alarm XX of YY” alert and description. If more than one alarm is activated, use the Up/Down arrow to scroll through the alarms list. (“XX” reference is the number of the alarm shown, and the “YY” ref- erence is the total number of alarms activated).

3.6Alarm History

A history of the 10 most recent alarms is kept in non-volatile memory complete with the date and time of their occurrence. The first alarm in the history is the most recent, and the 10th is the oldest. If the ALARM HISTORY is full (10 alarms) and a new alarm occurs, the oldest is lost and the newest is saved in ALARM HISTORY location 1.The rest are moved down the list by 1. ALARM HISTORY on new units may show the results of factory testing.

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