White Rodgers 2A37 User Manual

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 heat­ing applications.

The speed of response of the temperature sensitive
element makes it particularly applicable to warehouses,
factories, garages and similar installations.

TYPE 2A37

HEATING

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.

ELECTRICAL DATA
Switch Action: S.P.S.T. - Open on Rise

When the temperature in the controlled area rises, the
fluid in the coiled element expands, causing the contacts
in the switch mechanism to snap open, turning off the
heating system.

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.

SPECIFICATIONS

THERMAL DATA
Range: 20° to 90°F (-7° to 32°C)
Differential: 3° to 20°F (1.7° to 11°C) Adj.

PRINCIPLE OF OPERATION

As the air cools in the controlled area, the fluid in the coiled
element contracts. When the temperature drops to the
control setting, the contacts snap closed turning on the
heating system.

WHITE-RODGERS DIVISION

EMERSON ELECTRIC CO.
9797 REAVIS RD., ST. LOUIS, MO. 63123
[phone], FAX [phone]

9999 HWY. 48, MARKHAM, ONT. L3P 3J3
[phone], FAX [phone]

Printed in U.S.A.

PART NO. 37-1122B

Replaces 37-1122 & 37-9082

9548

INSTALLATION

The control may be mounted in any location provided that
the temperature and humidity of the air in which it is
located will not cause a condensation on the switch parts.

1. The control should be mounted approximately six feet
from the floor.

2. 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.

TYPE
2A37

CAUTION

Do not twist or uncoil the coiled bulb on the top of
the control case. Do not attach conduit through
coiled element to top of control. Instead, run con­duit to bottom of control.

LINE

HOT

N

ELECTRIC
HEATER

The diagram at left shows how a
2A37 can be used to control an
electric heater.

TYPE
11B09

The above diagrams show how a type 2A37 thermostat
can control several steam or hot water unit heaters. Any
number of unit heaters can be operated from one control
provided that the sum of the motor locked rotor currents
or the sum of the full load currents does not exceed the

SUPPLY

TYPE
11B09

TYPE
2A37

TYPE
11B09

RETURN

TO LINE SWITCH
AND POWER SUPPLY

electrical rating of the thermostat. The Type 11B09 Re­verse-acting Surface Hot Water Control is used to prevent
operation of the fans when the steam is off or when the
water temperature is too low for proper heating.

2