Liebert 50 & 60Hz User Manual

By selecting Run Diagnostics, maintenance personnel can check system inputs, outputs, and conduct 

a test of the microcontroller circuit board from the wall box control. A review of the system inputs and 

the microcontroller test can be done without interrupting normal operation.

• When this feature is selected, the controller is effectively turned off. When stepping from one load 

to the next, the previous load is automatically turned off. The loads can also be toggled on/off by 

selecting “ENTER”. Once turned on, the output will remain on for five minutes unless toggled off 

or the test outputs function is exited by selecting “MENU/ESC” (Compressor is limited to 15 sec-

onds on to prevent damage.  

The outputs are:

• Main  Fan
• Compr1 (3-ton)
• Compr1 & HGBP1
• Compr2
• Compr2 & HGBP2
• Compr1 & Compr2
• Chill Water/Gly (if present)
• Reheat 1
• Reheat 2
• SCR Reheats (if present)
• Humidifier
• Common Alarm

With the unit on and the fan running, the input states may be displayed for the following devices:

• Input  Power
• High Water in Pan
• High Head Comp1
• High Head Comp2
• Air Sail Switch (requires additional factory-installed components)
• Filter  Clog
• Humidifier Prob.
• Custom Alarm #1
• Custom Alarm #2
• Custom Alarm #3

Testing compressor output for more than a few seconds could damage the compressor. To 

eliminate damaging the compressor during testing, DO NOT test compressor output for more 

than a few seconds.

Extended unit operation in the test outputs mode for troubleshooting may cause damage to 

unit. DO NOT operate unit in the test outputs mode any longer than is necessary for 

troubleshooting.