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Series 40 Liquid Level Float Control

Counter Balance Snap-Action Movement
Mercoid Series 40
For general applications. The float assembly slides up and down the float rod. When the float rises to the top stop, it moves the operating arm up, and when it drops to the bottom stop, it moves the operating arm down. The mercury switch does not move until the operating arm has moved a definite amount, at which time it "snaps" to its alternate position. Enclosure is NEMA 1 general purpose.
 
Level Operated Controls:
To Open/Close Circuits by Mechanical Movement Snap-Action Type 46 (General Purpose NEMA-1)
Used where positive mercury switch action is desired when the operating lever is moved to a particular position (see Chart C for various circuits available). The mercury switch does not move until the operating arm has moved a definite amount at which time it “snaps” to its alternate position.
 
Direct-Action Type 47 (General Purpose NEMA-1)
Used where greater sensitivity and more over-travel is desired.  The mercury switch is mounted on the lever and moves with it. Requires less force and travel than the snap-action type. See Chart C for switch operations.
 
Direct Action with Spring Return-Type 47SR
For same application as Type 47 except this control is equipped with the spring return feature. The mercury switch is mounted on the lever arm with a spring assembly which returns the arm to the “Center” position when force is removed from the lever arm.
 
Standard Features
General Purpose-Types 46, 47, 47SR: 4-3/4" dia. steel case finished gray enamel. Glass fronted cover. Outlet box has 1/2" knockouts on both sides. Standard with bottom mounting base plate having two 13/64" holes 3" apart. 41⁄2" lever arm extended to right with seven lever holes 1/2" Centers.
 
Float Controls:
For vessels not under pressure Type 40-49
For use with rods and floats to open/close mercury switches by a change of liquid levels in vessels not under pressure. Example: to start and stop motor operated pumps, or perform other functions in changes of liquid level.
 
Type 40 Counter Balanced Snap-Action Movement
For general applications. The float assembly slides up and down the float rod. When the float rises to the top stop, it moves the operating arm up, and when it drops to the bottom stop, it moves the operating arm down. The mercury switch does not move until the operating arm has moved a definite amount, at which time it “snaps” to its alternate position. For minimum liquid level changes, see Chart C. Enclosure is NEMA-1 general purpose.
 
Type 49 Counter Balanced Direct Action
For use where closer differential in level change is desired between on and off operation. The mercury switch is mounted directly on the operating lever and moves with it. This control requires less operating force than the snap-action type. For minimum liquid level changes, see Chart C. Enclosure is NEMA-1 general purpose.  Type 49SRC Counter Balanced Direct-Action with Spring Return Similar to Type 49 except spring return assembly added to provide for stage operation. The spring return assembly holds the arm in a neutral position (contacts either open or closed) until the float engages upper or lower stop on rod, and actuates control contacts.  Can be used for high or low alarm. Enclosure is NEMA-1 general purpose.
 
Standard Features
General Purpose-Types 40, 49, 49SRC: 4-3/4" dia. steel case finished gray enamel. Glass fronted cover. Outlet box has 1/2" knockouts on both sides. Standard with bottom mounting base plate having two 13/64" holes 3" apart. Standard Construction: Furnished with bottom mounting and with lever arm extended to right.
 
Type 41 Plunger Type Snap-Action
For use on closed tanks (cannot be used on pressurized tanks). Rod and floats same as Type 40 except maximum rod length 4 ft. For minimum liquid level change, see Chart C. Standard Construction: Furnished with 1/4" NPT Bottom Connection only. Enclosure is NEMA-1 general purpose. For Weather Resistant NEMA-3 Case, specify Type 41W. When ordering, specify Type No. and Circuit.  Example: Type 41 - 156. Can be used for pump operation or day tanks.
 
Options and Accessories:
  • 37-29 - Two 2-1/8" x 5-1/2" cylindrical brass floats, 4' SS rod assembly, with brass stops.
  • 37-29A - Two 2-1/8" x 5-1/2" cylindrical brass floats, 6' SS rod assembly, with brass stops.
  • 37-29B - Two 2-1/8" x 5-1/2" cylindrical brass floats, 8' SS rod assembly, with brass stops.
  • 37-43 - 4-1/2" diameter 304SS float, 4' SS rod assembly, with stainless steel stops.
  • 37-43A - 4-1/2" diameter 304SS float, 6' SS rod assembly, with stainless steel stops.
  • 37-43B - 4-1/2" diameter 304SS float, 8' SS rod assembly, with stainless steel stops.
  • 37-49 - 4-1/2" diameter copper float, 4' SS rod assembly, with brass stops.
  • 37-49A - 4-1/2" diameter copper float, 6' SS rod assembly, with brass stops.
  • 37-49B - 4-1/2" diameter copper float, 8' SS rod assembly, with brass stops
 
Ordering Information:
Model Number Description
40-2-R6 Liquid level control, snap action mercury switch, SPST switch opens when lever is down, with bottom flange for mounting. (NOTE: floats & rods sold separately, please see accessories below.)
40-3-R6 Liquid level control, snap action mercury switch, SPST switch closes when lever is down, with bottom flange for mounting. (NOTE: floats & rods sold separately, please see accessories below.)
 
 
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