Emerson Liebert Economizer Solutions User Manual

The Liebert Air Economizer ships with sensors to determine the temperature and humidity of return air 

and outdoor air. The sensors and wiring to connect them are in boxes inside the Liebert Air Economizer:

• Outdoor air sensor
• Return air sensor
• Supply air limit thermistor (factory-connected to the main interface board)

These must be installed and connected to the primary cooling unit. The outdoor air sensor and return 

air sensor connections for the Liebert DS and Liebert CW are shown in Figure 6. Connect the supply 

air limit thermistor as shown in Figure 7 (it must be routed from the cooling unit and secured). The 

illustration shows connections for the Liebert DS and Liebert CW.

Turn Off all power to the indoor cooling unit before connecting cables or wires. Failure to do so 

may damage this equipment.

B

C

D

DETAIL C

DETAIL B

Both Sensors and Cables
are Shipped in Boxes
Inside the Liebert
Air Economizer

Outdoor Air T/H
Sensor
(identified with
outdoor label)

Return Air
T/H Sensor

DETAIL D

Connect P67 on the
Control Board to P66 on the
Return Air T/H Sensor
Using Cable Provided

Secure Ring Terminal
(for Sensor Cable Shield)
Into the Back of the Electric Box
(Earth Ground)

Mount Return Air
T/H Sensor Indoors,
Above Unit Return

Connect P67 on the
Return Air T/H Sensor
to P66 on the Outdoor
Air T/H Sensor Using
Cable Provided

Connect P66 on the
Return Air T/H Sensor
to P67 on the Control Board
Using Cable Provided

Mount Outdoor
Air Sensor Inside
Outdoor Air Plenum

Secure Ring Terminal
(for Sensor Cable Shield)
Into Metal Duct
(Earth Ground)

Connect P66 on the
Outdoor Air T/H Sensor
to P67 on the Return
Air T/H Sensor
Using Cable Provided

Route Cable Through
Customer-Created Hole
In Plenum, Then Seal

Outdoor Air
T/H Sensor

Return Air

T/H Sensor

FRONT VIEW

Both Po

ssible Lo

w-Voltag

e

Compar

tments S

hown.

Identify 

Which A

pplies.

DPN001449
Pg. 4, Rev. 2