Table 12 Setup functions, default values and allowable ranges. Liebert 8 Tons, 50 & 60Hz, 60Hz

Microprocessor Control

3.10.7 CW Flush (For Systems With a Modulating Chilled-Water Valve)

This function shows the interval time at which the system will perform a modulating chilled-water valve system flush cycle. The factory default is 24 (hours) and is programmable from 0 (hours) which signifies to never flush, to 99 (hours) which signifies to flush after every 99 hours of valve non-use. If the valve is called on by the control to open within the programmed interval time, the timer will be reset to 0. The flush cycle is active even when the fan is turned off, but power is applied to the unit.

When the interval timer reaches the programmed time, the valve will be opened for 3 minutes to flush any contaminates which may have collected in the system.

Table 12 Setup functions, default values and allowable ranges

Function Default

Restart Time Delay

C/F Degrees

Humidity Control

Valve Time

CW Flush

0.1

° F

Rel

165

24

Range

0 to 9.9 min

(0 = manual restart)

° C or ° F

Relative or Absolute

50 to 250 sec(s)

0 to 99 hours

3.11 Change Passwords

The display will prompt the operator to enter a three digit password when attempting to make changes. The system includes two (2) passwords, one for setpoints and one for setup. The system allows the password to be changed by first entering the default password set at the factory (1-2-3) for setpoints and (3-2-1) for setup. The password function provides system security, so that only authorized personnel are allowed to make changes to the system. (If unauthorized changes are being made, the passwords may be compromised and new ones should be selected). The password function can be disabled by setting DIP switch 8 in the wallbox to OFF, then resetting power to the unit.

3.12 Calibrate Sensors

The temperature and humidity sensors can be calibrated by selecting the CALIBRATE SENSORS menu item. The temperature sensor can be calibrated ±5°F, while the humidity sensor can be calibrated ±10% RH. When calibrating the humidity sensor, the value shown will always be % RH, even though absolute humidity control may be selected. If absolute humidity control is selected, the Normal Status Display will display the adjusted reading. This reading may not agree with the relative humidity reading displayed while in calibration.

If the sensors are subject to frequent wide temperature and humidity swings, it may be necessary to shorten the cycling by increasing the sensor response time delay. If the sensors are located too close to the air discharge, they will likely experience rapid swings in measurement. The factory default is 30 seconds. Another method in reducing compressor cycling is to increase the temperature and/or humidity sensitivity.

3.13 Alarm Enable

Each alarm can be disabled or enabled. Use the UP/DOWN ARROW to select a particular alarm, press Enter to select either enable or disable. Then press Enter again to store the change. When the alarm is disabled it will NOT report to either the wallbox beeper or the common alarm relay. The high water in condensate pan and high head alarms cannot be disabled.

NOTE

The high-water alarm will automatically shut the unit off.

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Microprocessor Control

3.14 Alarm Time Delay

Each individual alarm can be programmed with a time delay (Table 13), causing the unit to delay a

specified amount of time (0-255 seconds) before recognizing the alarm. The alarm condition must be present for the full amount of the time delay before the alarm will sound. If the alarm condition is diverted prematurely, the alarm will not be recognized and the time delay will automatically reset.

NOTE

For software alarms such as “loss of power” and “short cycle,” the time delay should be left at the factory default of 0.

Table 13 Alarm default time delays

Alarm

Default Time Delay

(seconds)

Hum Prob

Chng Fltr

Custom Alarm #1

Custom Alarm #2

Custom Alarm #3

High Temperature

Low Temperature

High Humidity

Low Humidity

Short Cycle 1 & 2

Loss of Power

30

30

0

0

2

2

0

30

30

0

0

3.15 Common Alarm Enable

Each individual alarm can be selected to activate/deactivate the common alarm relay. If the energize common alarm function is set to YES, the relay is energized immediately as the alarm is enunciated, and de-energized when the alarm condition has cleared. If the alarm is completely DISABLED, the alarm has no effect on the common alarm relay. Use the UP/DOWN arrows to scroll to a particular alarm, press the ENTER button to select it, then press the ENTER key again to select Yes or No.

3.16 Custom Alarms

The custom alarm messages can be selected from a list of standard alarm messages, or the operator can write his/her own message. A MAXIMUM OF THREE (3) ALARM MESSAGES CAN BE CUS-

TOMIZED.

The text for custom alarms can be changed at any time by selecting “CUSTOM ALARMS”. To change the text for a custom alarm, select the alarm you would like to change, 1, 2 or 3. Using the UP/DOWN arrows, step through the list of seven standard alarm messages (listed below) and two custom alarms.

Select the alarm message desired and store it by pressing ENTER.

• SMOKE DETECTED

• CUSTOM 2

• CUSTOM 3

• STANDBY GC PUMP

• WATER FLOW LOSS

• STANDBY UNIT ON

• CUSTOM 1

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