White Rodgers 201-20, 201-8 Installation Instructions
WHITE-RODGERS
Operator: Save these instructions for future use!
FAILURE TO READ AND FOLLOW ALL INSTRUCTIONS CAREFULLY
BEFORE INSTALLING OR OPERATING THIS CONTROL COULD CAUSE
PERSONAL INJURY AND/OR PROPERTY DAMAGE.
This Hydraulic-Action temperature control is readily applicable for many types of commercial or industrial refrigeration applications.
The speed of response of the temperature sensitive
element makes it particularly applicable to display cases,
unit coolers, walk-in boxes, etc., where there is no excessive humidity.
TYPE 201
REFRIGERATION
TEMPERATURE CONTROL
Adjustable Differential
INSTALLATION INSTRUCTIONS
DESCRIPTION
THESE CONTROLS MUST BE INSTALLED BY A
QUALIFIED INSTALLER.
Do not exceed the specification ratings.
All wiring must conform to local and national electrical
codes and ordinances.
This control is a precision instrument, and should be
handled carefully. Rough handling or distorting components could cause the control to malfunction.
This control has been accurately calibrated at the factory.
Any attempt to calibrate this control will void the White-
Rodgers warranty.
When the temperature in the controlled area rises, the
fluid in the coiled element expands, causing the contacts
in the switch mechanism to snap closed, turning on the
refrigeration system.
Observe the following general rules when selecting a
control location:
1. The switch mechanism of this control may be mounted
in any location, provided that the temperature and
humidity of the air in which it is located do not cause
condensation on the switch parts.
2. It should be located so as to be in an average
PRECAUTIONS
CAUTION
To prevent electrical shock and/or equipment
damage, disconnect electric power to system at
main fuse or circuit breaker box until installation
is complete.
WARNING
Do not use on circuits exceeding specified voltages. Higher voltages will damage control and
could cause shock or fire hazard.
PRINCIPLE OF OPERATION
As the refrigeration system cools the controlled area, the
fluid in the coiled element contracts. When the temperature reaches the control setting, the contacts snap open,
turning off the system.
INSTALLATION
temperature of the controlled area.
3. Never locate control on or near an outside wall.
4. Don’t locate it close to a false source of heat or cold
such as strong light, sunlight, hot or cold water pipes
in wall, etc.
WHITE-RODGERS DIVISION
EMERSON ELECTRIC CO.
9797 REAVIS RD., ST. LOUIS, MO. 63123
(314) 577-1300, FAX (314) 577-1517
9999 HWY. 48, MARKHAM, ONT. L3P 3J3
(905) 475-4653, FAX (905) 475-4625
Printed in U.S.A.
PART NO. 37-1121B
Replaces 37-1121, 37-9088 & 37-9193
9545
INSTALLATION CONT.
5. If the electric conduit goes to a warmer room, put rock
wool around the wires in the conduit where it enters
the control to prevent the flow of warm moist air into
the switch.
WIRING
All wiring should be done in accordance with local and national electrical codes and ordinances.
If the manufacturer of the cooling equipment has supplied
a wiring diagram, follow such recommendations. The
following diagrams show general use of these controls.
Temperature
control
To line switch
and power supply
HOT
GND
Circuit showing temperature control to open and
close refrigerant valve. Suction pressure control
starts and stops compressor through motor starter.
High side
pressure control
(if used)
CAUTION
Do not twist or uncoil the coiled element on top of
the case. Do not attach conduit to top of control
through the coiled element. Run conduit to bottom of control instead.
Circuit showing temperature control controlling compressor directly.
To line switch
and power supply
Motor
starter
High side
pressure
control
Suction
pressure
control
Temperature
control
Solenoid
refrigerant
valve
SETTING THE CONTROL
CONTROLS WITH ADJUSTABLE DIFFERENTIAL
The movable indicator points to the temperature at which the
compressor starts. The fixed indicator points to the temperature
at which the compressor will stop. The difference between these
two indicators is the differential.
To set the control, do the following:
1. Use a screwdriver in the slot on the front of the control to turn
the dial so that the fixed indicator (B) points to the temperature at which the compressor is to stop.
2. Turn the differential adjusting screw (C) until the movable
indicator (D) points to the temperature at which the compressor is to start.
“B” Fixed indicator
(cut-out point)
“C” Differential
adjusting screw
“D” Movable indicator
(cut-in point)
2
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