GENERAL
MISUSE OR MISAPPLICATION OF THIS
PRODUCT MAY CAUSE EXPLOSION AND
PERSONAL INJURY. THESE INSTRUCTIONS
MUST BE THOROUGHLY READ AND UNDER-
STOOD BEFORE UNIT IS INSTALLED.
Temperature variations of a liquid filled sensing bulb
are hydraulically transmitted to a bellows or
diaphragm which either actuates or deactuates one
or two snap-acting switches at a predetermined set
point(s). Set points are adjusted by turning an exter-
nal calibrated knob and pointer (B, E types) or inter-
nal adjustment screw (C, F types).
MAXIMUM TEMPERATURE: THE HIGHEST
TEMPERATURE TO WHICH A SENSING ELE-
MENT MAY BE OCCASIONALLY OPERATED
WITHOUT ADVERSELY AFFECTING SET POINT
CALIBRATION AND REPEATABILITY. MAXIMUM
TEMPERATURE STATED IN LITERATURE AND ON
NAMEPLATE MUST NEVER BE EXCEEDED, EVEN
BY SURGES IN THE SYSTEM. OCCASIONAL
OPERATION OF UNIT UP TO MAX.
TEMPERATURE IS ACCEPTABLE (E.G. START-
UP, TESTING). CONTINUOUS OPERATION
SHOULD BE RESTRICTED TO THE DESIGNATED
ADJUSTABLE RANGE.
TOOLS NEEDED
Screwdriver
Adjustable Wrench to 1 1/2”
MOUNTING
INSTALL UNIT WHERE SHOCK, VIBRATION
AND TEMPERATURE FLUCTUATIONS ARE
MINIMAL. ORIENT UNIT SO THAT MOISTURE IS
PREVENTED FROM ENTERING THE ENCLO-
SURE. IT IS IMPERATIVE THAT PROPERLY
RATED EXPLOSION-PROOF SEALING FITTINGS
BE USED FOR ELECTRICAL WIRE ENTRY. DO
NOT MOUNT UNIT IN AMBIENT TEMPERATURES
EXCEEDING PUBLISHED LIMITS.
ALWAYS HOLD A WRENCH ON THE
CONNECTION HEX WHEN INSTALLING
LOCAL MOUNTED UNITS. DO NOT TIGHTEN BY
TURNING ENCLOSURE. THIS WILL DAMAGE
SENSOR AND WEAKEN SOLDER OR WELDED
JOINTS.
120 Series remote mounted temperature controls
should be mounted vertically (temperature assembly
facing down) or horizontally (electrical conduit facing
up) Controls may be surface mounted via the 4-1/4”
screw clearance holes on the enclosure or through
the use of a mounting bracket (See Mounting
Dimensions).
Breather Drain Option M450: Types C120, F120
(Not available on FM approved units)
Mount with breather drain facing down and conduit
connection facing up (See Figure I). The conduit
connection must be properly sealed (potted) for this
type of installation.
Breather Drain Option M450: Types B121,
B122, E121 & E122
(Not available on FM approved units)
Mount in vertical position with temperature assembly
and breather drain facing down (See Figure 2).
Installation and Maintenance
Instructions
IMT120-03
Please read all instructional literature carefully and thoroughly before starting. Refer to the final page for the listing of
Recommended Practices, Liabilities and Warrantees.
120 Series Explosion Proof*
Temperature Controls
Remote Types E121, E122,
E122P, F120; Local Types B121,
B122, C120
FM, UL & CSA listed; Meets Divisions 1 & 2: Class 1,
Groups B, C & D; Class II, Groups E, F & G;
and Class III & Heat Trace Units
NOTE: CSA, Class I, Group B approval does not
apply to controls with option code “1530”.
Part I - Installation
Figure 1: Types C120, F120
Figure 2: Types B121, B122, E121, E122
* Enclosures are designed to withstand gas vapor explosions without bursting or loosen-
ing of joints, and are capable of arresting the propagation of flame from the interior of the
enclosure to the surrounding atmosphere.
1
Breather Drain
(facing down)
Potted
Conduit
Connection
Breather Drain
(facing down)
U N I T E D E L E C T R I C
C O N T R O L S
