Component Operation and Maintenance 39
Firestat
The optional firestat is a bimetal operated sensing device with a normally closed switch. This device
will shut down the entire unit when the inlet air temperature exceeds a preset point. It is connected
between terminals 1 and 2 at plug P39.
Smoke Detector
The optional smoke detector power supply is located on the base of the upflow units, and at the top of
downflow units. It is constantly sampling return air through a tube. No adjustments are required.
Water Detection Sensor
The optional water detection sensor contains a solid state switch that closes when water (or other con-
ductive liquid) is detected by the twin sensor probes. The sensor is hermetically sealed in all thread
PVC nipple and is to be mounted where water problems may occur.
The sensor should be located 6-8 feet (2 to 2.5 meters) from the environmental control unit in a wet
trap or near a floor drain. It should not be mounted directly under the unit. Wire the sensor to unit
using NEC Class 2, 24 volt wiring. Run wires to the terminal strip on the wire raceway in the com-
pressor compartment and connect them to terminals 24 and 50-56.
Figure 7 Recommended liquid sensor locations
Remote Shutdown
A connection point is provided for customer supplied remote shutdown devices. This terminal strip is
located at the top of upflow units, and at the base of downflow units. Terminals 37 and 38 on the ter-
minal strip are jumpered when no remote shutdown device is installed.
!
CAUTION
Do not use near flammable liquids or for flammable liquid detection.
Recommended
Liquitect
location
Liebert
unit
Floor drain
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