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(Supersedes PK471-3)
PK471-4
WCRT
161-562767-001
DECEMBER, 1998
4
OPERATION INSTRUCTIONS
Installation
and
WCRT Weather-Corrosion
Resistant Room
Thermostat
© 2010 Chromalox, Inc.
Temperature Switch
Maximum Rating
Model Range (°F) Action Description 120 Vac 240 Vac 277 Vac
Full Load Inductive 16.0A 12.0A 10.0A
WCRT-100 40-100 SPDT Locked Rotor 80.0A 60.0A 55.0A
Non-Inductive 25.0A 25.0A 22.0A
Pilot Duty 125VA 125VA 125VA
Specifications – Table A
GENERAL
Type WCRT thermostats are intended for use in harsh environ-
ments. They tolerate continuous spraying with water, high humid-
ity, airborne contaminates and moderately corrosive conditions.
The nickel plated sensing bulb is attached directly to the bottom of
the case where it is shielded from damage or accumulations of
insulating particles. The molded Noryl case is sealed at the cover
with a neoprene gasket and the adjusting knob opening is closed
with a lubricated O ring. Underwriters Laboratories has tested the
WCRT and found it meets the requirement for NEMA 4X areas.
High levels of accuracy and sensitivity, 2
1
/2° differential, are pro-
vided by the WCRT. Switching is done by heavy duty, precision,
single stage, SPDT line voltage snap action switch. Setting is
accomplished by rotating the adjusting knob. The dial face is print-
ed with large, contrasting numbers and letters on a lustrous back-
ground for good visibility. Color coding clearly identifies the func-
tion of each conductor.
Applications – Automatically controls room temperature by turn-
ing electric air heaters on and off. Can be used to control the air
heaters directly, within thermostat rating. For higher ratings use
thermostat with magnetic contactor. Place thermostat on inside wall,
away from undue heating or cooling influences, about 4 feet above
the floor.
NOTICE: Type WCRT thermostats are designed for temperature
control service only. Because they do not fail safe, they should
not be used for temperature limiting duty.
WWAARRNNIINNGG::
Users should install adequate back-up
controls and safety devices with their electric heat-
ing equipment. Where the consequences of failure
may be severe, back-up controls are essential.
Although the safety of the installation is the
responsibility of the user, Chromalox will be
glad to make equipment recommendations.
Principle of Operation – Control action of these thermostats is
provided through the principle of liquid volume change. With a
variation in temperature, the liquid in the sensing element expands
or contracts, causing a bellows to actuate the switching mechanism.
WARNING: Not for use in hazardous environments as
described in National Electrical Code. Failure to com-
ply can result in explosion or fire.
LO Setting is positive open (black to red) for heating loads and
is positive closed (black to blue) for cooling loads.
Note: It is not recommended to switch systems directly from heat-
ing to cooling and vice versa.
Figure 1
UL LISTED