Float

Product Overview

Bulletin 840 Type 7 & 9

Bulletin 840 Automatic Float Switches

• Liquid Level Sensitivity From 2 to 5 Inches
  
• 0.6 to 3.8 lbs Switch Operating Force
  
• 2 Pole Contact Configuration
  
• Tank to Sump Convertibility
  
• NEMA A600 and NEMA N300 Contact Ratings
  
• Type 1, Type 4, and Type 7 & 9 Enclosures
  

Standards Compliance and Certifications

Standards Compliance

UL 508
UL 698 (Haz. Loc.)
UL 1604 (Haz. Loc.)
CSA 22.2 No. 14
NEMA ICS-2

Certifications

File and Guide Numbers
Bulletin 840	UL		CSA
	File Number	Guide Number	File Number	Class
	E14842 E53048 (Haz. Loc.)⋆	NKPZ, NKPZ7 NOWT	LR1234	3211-06
	Hazardous Location Enclosure not CE compliant.
⋆ Style A is listed for hazardous locations. Styles B, C, D, and DS are not.

Bulletin 840 Style A Shown With Cover Removed

Description

Bulletin 840 Automatic Float Switches are heavy duty horsepower or control circuit rated devices which can be used to control and monitor liquid levels in a tank or sump. As the liquid level rises or falls in a sump or tank, at a preset level the switch can either start a motor to adjust the liquid level or activate a circuit to turn on a light or sound an alarm. Bulletin 840 Float Switches are designed for long life and heavy duty operation. They are offered in five different styles with many different float operator assemblies. These assemblies come in either floor or base mounted versions to meet a wide range of applications.

Applications

• Water Treatment Plants
  
• Plating Plants
  
• Controlling Irrigation Channels
  
• Almost any other tank or sump application to control or monitor liquid levels
  

Style A — Industrial Low Operating Force



Style A

• Wall or floor mounting accessories
  
• 2-pole switch: 1 N.O. and 1 N.C., 2 N.O., or 2 N.C. contacts
  
• Converts from tank to sump operation
  
• Maximum switch operating force of 0.9 lbs
  
• Sensitive to liquid level changes of 2 in.
  
• Type 1, Type 4, and Type 7 & 9 enclosures
  
• Contact ratings: NEMA A600 and N300
  
• Switch temperature operating range from -22…+150 °F (-30…+66 °C)
  

Style B — Heavy Duty Industrial



Style B

• Wall or floor mounting accessories
  
• 2-pole switch with N.O. contacts
  
• Converts from tank to sump operation
  
• Maximum switch operating force of 3.8 lbs
  
• Sensitive to liquid level changes of 5 in.
  
• Type 1, Type 4, and Type 7 & 9 enclosures
  
• Contact ratings: NEMA A600 and N300
  
• Switch temperature operating range from -22…+150 °F (-30…+66 °C)
  

Styles D & DS — Low Cost, Low Operating Force



Style D and DS

• Wall or floor mounting accessories
  
• 2-pole switch with N.O. contacts
  
• Style D, tank operation only
  
• Style DS, sump operation only
  
• Maximum switch operating force of 0.6 lbs
  
• Sensitive to liquid level changes of 3 in.
  
• Type 1 enclosure only
  
• Contact ratings: NEMA A600 and N300
  
• Switch temperature operating range from -22…+150 °F (-30…+66 °C)
  

Technical Data

Technical Terms

Tank Operation — When the liquid in a tank reaches a preset low level, the float switch will start a pump to begin filling the tank. When the liquid level reaches a preset high level, the float switch will stop the pump.

Sump Operation — Liquid is being collected in a sump. When the liquid reaches a preset high level, the float switch will start a pump to empty the sump. When the liquid reaches a preset low level, the float switch will stop the pump.

Operating Force — Contact force required to trip the float switch. Operation depends on the type of switch, liquid, float, and float operator assembly.

Turbulence — Waves or agitation in the liquid. Excessive turbulence may cause improper switch operation — for example, early switching or switching between operating points.

Buoyancy — Force supporting the float equal in magnitude to the weight of the displaced liquid.

Theory of Operation

Bulletin 840 Float Switches provide automatic control for motors that pump liquids from a sump or into a tank. The switch must be installed above the tank or sump, and the float must be in the liquid for the float switch to operate. Tank Operation: A float operator assembly is attached to the float switch by a rod, chain or cable. The float switch is actuated based on the location of the float in the liquid. The float switch contacts are open when the float forces the operating lever to the UP position. As the liquid level falls, the float and operating lever move downward. When the float reaches a preset low level, the float switch contacts close, activating the circuit and starting the motor. The contacts can directly activate a motor or provide input for a logic system to fill the tank. As the liquid level rises, the float and operating lever move upward. When the float reaches a preset high level, the float switch contacts open, deactivating the circuit and stopping the motor. Sump Operation: Sump operation is opposite tank operation.

Figure 1
Tank and Sump Operation



Temperature Range (Switch)

The temperature range for the switch mechanism at +32 °F (0 °C) or below is based on the absence of freezing moisture, water, or other fluids that may solidify and impede the operation of the control. Temperature ratings are as follows:

    Operating:     –22…+150 °F (–30…+66 °C)

    Storage:         –22…+200 °F (–30…+93 °C)

Temperature Range (Float)

The temperature range for the float mechanism at +32 °F (0 °C) or below is based on the absence of freezing moisture, water, or other fluids that may solidify and impede the operation of the control. Temperature ratings are as follows:

     Operating and Storage:
     –22…+200 °F (–30…+93 °C)

Conversions

Bulletin 840 Styles A and B Float Switches are assembled for tank operation but can be easily converted to sump operation. Style A switches can be changed from tank to sump operation by moving the float rod to the opposite end of the double arm lever.

Styles B switches can be converted in either of the following ways:

• Remove the lever, turn the shaft 90° counterclockwise and replace the lever in its original position.
  

• Remove the lever and replace 180° from the original position.
  

Style D is for tank operation only. Style DS is for sump operation only. These switches cannot be converted.

Contacts

Bulletin 840 Float Switches have a snap action mechanism for quick-make and quick-break contact operation. This feature provides high snap-through forces once the mechanism has traveled the required distance. See table below.

Maximum Contact Rating per Pole
AC — NEMA A600					DC — NEMA N300
Max. V AC	Make	Break	Make	Break	Max. V DC	Make	Break
120	60 A	6.0 A	7200V A	720V A	—	—	—
240	30 A	3.0 A	7200V A	720V A	125	2.2 A	2.2 A
480	15 A	1.5 A	7200V A	720V A	250	1.1 A	1.1 A
600	12 A	1.2 A	7200V A	720V A	—	—	—

Maximum Horsepower Ratings
Style	Single-Phase AC		2- or 3-Phase AC		DC
	115V	230V	115V	230-460-575V	32V	115V	230V
A — Tank or Sump	1	1	—	—	.025	0.25	0.125
B — Tank or Sump	1.5	3	—	2	—	1	1
D — Tank	1.5	2	2	3	0.25	0.5	0.5
DS — Sump	1.5	2	2	3	0.25	0.5	0.5

Contact Wiring Configurations


Ordering Information

When ordering a Bulletin 840 Automatic Float Switch, two cat. nos. must be specified. The first catalog number is used to order the switch. The second cat. no. is used to order the float operator assembly and to indicate cable length modification.

How to Order

Step 1:        Basic Device
Select a catalog number for the Float Switch.
See Product Selection

Step 2:        Float Operator Assembly
Select float operator assembly.
See Float Operator Assemblies …Single Arm Lever, Separate Pulleys

Step 3:        Modifications and Accessories
If required, select appropriate modifications and accessories to the float operator assembly.
See Modifications and Accessories.

Catalog Number Explanation

Note:Catalog numbers must not include blank spaces.

840	–	A		1		1
		a		b		c

a
Style of Device
Code	Description
A	See Product Overview Applications
B
C
D
DS

b
Enclosure Type
Code	Description
1	Type 1
4	Type 4
7	Type 7 & 9

c ⋆
Contact Modification to Style A devices only
Code	Description
—	1 N.O. and 1 N.C.
1	2 N.O.
2	2 N.C.

⋆ 2 N.O. or 2 N.C. contact options are available for Style A devices only.

Product Selection

Style AType 4

Style A⋆  — Tank or Sump Operation
Maximum Horsepower Ratings							Type 1 Enclosure	Type 4 Enclosure (Fiberglass Polyester)	Type 7 & 9 Enclosure‡
Single-Phase AC		2 or 3-Phase AC		DC
115V	230V	115V	230/460/575V	32V	115V	230V	Cat. No.	Cat. No.	Cat. No.
1	1	—	—	0.25	0.25	0.125	840-A1⋆	840-A4⋆	840-A7⋆

Style BType 1

Style B — Tank or Sump Operation
Maximum Horsepower Ratings							Type 1 Enclosure	Type 4 Enclosure (Fiberglass Polyester)	Type 7 & 9 Enclosure‡
Single-Phase AC		2 or 3-Phase AC		DC
115V	230V	115V	230/460/575V	32V	115V	230V	Cat. No.	Cat. No.	Cat. No.
1.5	3	—	2	—	1	1	840-B1	840-B4	840-B7

Styles D & DSType 1

Style D — Tank or Sump Operation
Maximum Horsepower Ratings							Type 1 Enclosure
Single-Phase AC		2 or 3-Phase AC		DC
115V	230V	115V	230/460/575V	32V	115V	230V	Cat. No.
1.5	2	2	3	0.25	0.5	0.5	840-D1

Style DS — Tank or Sump Operation
Maximum Horsepower Ratings							Type 1 Enclosure
Single-Phase AC		2 or 3-Phase AC		DC
115V	230V	115V	230/460/575V	32V	115V	230V	Cat. No.
1.5	2	2	3	0.25	0.5	0.5	840-DS1
⋆ Style A devices are supplied with 1 N.O. and 1 N.C. contact. For 2 N.O. contacts, add Suffix Code 1 to the catalog number. For 2 N.C. contacts, add Suffix Code 2 to the catalog number.
‡ Class I Groups C, D. Class II Groups E, F, G

Float Operator Assemblies

A Float Operator Assembly must be included with the basic device for the float switch to operate. Select and specify a catalog number that meets your requirements. Select modifications and accessories to the Float Operator Assembly from tables on Ordering Modifications.

All Allen-Bradley Float Operator Assemblies come equipped with a number of plated steel or stainless steel assembly parts to allow wall or floor mounting and to accommodate different tank or sump depths. The plated steel and stainless steel assembly parts are made of the material listed in the table below.

Operator Assembly Parts Material

Stainless Steel
Assembly Part	Material
3/8 in. Rod	Two 3 ft tubes (Type 304) with coupling (Type 303)
Cable	15 ft Cable, (Type 304)
Stop Collars	Type 303
Float	Type 304

Single Arm Lever

Float is fixed to one end of the rod. Adjustable stop collars at top of the rod operate the switch. The rod may need guides to stabilize vertical float movement. Because of the unlimited number of possible mounting arrangements, guides must be provided by the user. See maximum rod lengths table below.

Base-Mounted



Stainless Steel Operator Assemblies include the following:

• Two 3 ft lengths of 3/8 in. tubing with coupling
  
• Two adjustable stop collars
  
• One fixed stop collar (with Cat. No. 840-1BCE only when required)
  
• Stainless Steel Float
  

Type	Style	Stainless Steel
		⋆	Cat. No.
1	A,D,DS	A	840-1AD
	B	F	840-1BCE
4	A	A	840-1AD
	B	F	840-1BCE
7 & 9	A	A	840-1AD
	B	F	840-1BCE

Floor-Mounted



Stainless Steel Operator Assemblies include the following:

• 20 in. of 1 in. pipe
  
• Two 3 ft lengths of 3/8 in. tubing with coupling
  
• Two adjustable stop collars
  
• One fixed stop collar (with Cat. Nos. 840-2BC1, -2B47, -2C47 only when required)
  
• Stainless Steel Float
  
• Floor mounting bracket
  

Switch ordered separately. See Product Selection.

Type	Style	Stainless Steel
		⋆	Cat. No.
1	A	A	840-2A1
	B	F	840-2BC1
4	A	A	840-2A47
	B	F	840-2B47
7 & 9	A	A	840-2A47
	B	F	840-2B47

Maximum Rod Lengths
Style	Stainless Steel
A	9 ft
B	18 ft
D, DS	9 ft

⋆ See Float Size Table, .

Double Arm Lever

The double arm has a counterweight to offset weight of rod and float. The float moves up and down between stops on the rod so that large changes in liquid level only move the rod a short distance. Top of the rod is fixed to switch lever. The rod may need user-provided guides to stabilize vertical float movement. See Maximum Rod Lengths table below.

Base-Mounted



Stainless Steel Operator Assemblies include the following:

• Half Arm Lever (when required)
  
• Double Arm Lever
  
• Counterweight
  
• Two 3 ft lengths of 3/8 in. tubing with coupling
  
• Three adjustable stop collars
  
• One fixed stop collar
  
• Stainless Steel Float
  

Switch ordered separately. See Product Selection.

Type	Style	Stainless Steel
		⋆	Cat. No.
1	A	A	840-6A1
	B	F	840-6BCE
4	A	A	840-6A1
	B	F	840-6BC47
7 & 9	A	A	840-6A47
	B	F	840-6BCE47

Floor-Mounted



Stainless Steel Operator Assemblies include the following:

• Half Arm Lever (when required)
  
• Double Arm Lever
  
• Counterweight
  
• Floor mounting bracket
  
• 20 in. of 1 in. pipe
  
• Two 3 ft lengths of 3/8 in. tubing with coupling
  
• Three adjustable stop collars
  
• One fixed stop collar
  
• Stainless Steel Float
  

Switch ordered separately. See Product Selection.

Type	Style	Stainless Steel
		⋆	Cat. No.
1	A	A	840-7A1
	B	F	840-7BC1
4	A	A	840-7A1
	B	F	840-7BC1
7 & 9	A	A	840-7A47
	B	F	840-7B47

Double Parallel Arms

Used with unguided rods up to 33 ft long. The float moves up and down between stops on the rod so that large changes in liquid level only move the rod a short distance. Parallel levers keep the rod vertical and help limit sideways movement. Top of the rod is fixed to switch lever. See Maximum Rod Lengths table below.

Base-Mounted



Stainless Steel Operator Assemblies include the following:

• Additional Double Arm Levers
  
• Counterweight
  
• Two 3 ft lengths of 3/8 in. tubing with coupling
  
• One adjustable stop collar
  
• One fixed stop collar
  
• Stainless Steel Float
  

Switch ordered separately. See Product Selection.

Type	Style	Stainless Steel
		⋆	Cat. No.
1	A	A	840-8A1
	B	F	840-8B1
4	A	A	840-8A4
	B	F	840-8B4
7 & 9	A	A	840-8A47
	B	F	840-8B47

Floor-Mounted



Stainless Steel Operator Assemblies include the following:

• Additional Double Arm Levers
  
• Counterweight
  
• Floor mounting bracket
  
• 20 in. of 1 in. pipe
  
• Two 3 ft lengths of 3/8 in. tubing with couplings
  
• One adjustable stop collar
  
• One fixed stop collar
  
• Stainless Steel Float
  

Switch ordered separately. See Product Selection.

Type	Style	Stainless Steel
		⋆	Cat. No.
1	A	A	840-9A1
	B	F	840-9B1
4	A	A	840-9A4
	B	F	840-9B4
7, 9	7, 9	A	840-9A47
	B	F	840-9B47

Maximum Rod Lengths
Style	Stainless Steel
A, B	33 ft

⋆ See Float Size Table, Float Size Table.

Double Arm Lever, Double Pulley

A cable runs over a self-supported double pulley. The cable has a float fixed at one end and a counterweight at the other end. Adjustable stop collars on the cable move the switch operating lever.

Base-Mounted



Stainless Steel Operator Assemblies include the following:

• Double Pulley Bracket
  
• 15 ft cable/cast iron counterweight assembly
  
• Two adjustable stop collars
  
• Stainless Steel Float
  

Switch ordered separately. See Product Selection.

Type	Style	Stainless Steel
		⋆	Cat. No.
1	B	F	840-4BC1
4	B	F	840-4B4
7 & 9	A	A	840-4A47
	B	F	840-4BC47

Floor-Mounted



Stainless Steel Operator Assemblies include the following:

• Double Arm Bracket
  
• Floor mounting bracket
  
• 20 in. of 1 in. pipe
  
• 15 ft cable/cast iron counterweight assembly
  
• Two adjustable stop collars
  
• Stainless Steel Float
  

Switch ordered separately. See Product Selection.

Type	Style	Stainless Steel
		⋆	Cat. No.
1	B	F	840-5BC1
4	B	F	840-5B4
7 and 9	A	A	840-5A47
	B	F	840-5B47

Double Arm Lever, Single Sheave Wheel

Used with Style A switch only. A cable runs over a single pulley mounted on top of float switch. The cable has a float fixed at one end and a counterweight at the other end. Adjustable stop collars on the cable move the switch operating lever.

Base-Mounted



Stainless Steel Operator Assemblies include the following:

• Pulley Assembly
  
• 15 ft cable/cast iron counterweight assembly
  
• Two adjustable stop collars
  
• Stainless Steel Float
  

Switch ordered separately. See Product Selection.

Type	Style	Stainless Steel
		⋆	Cat. No.
1	A	A	840-4A1
4	A	A	840-4A4

Floor-Mounted



Stainless Steel Operator Assemblies include the following:

• Pulley Assembly
  
• Floor mounting bracket
  
• 20 in. of 1 in. pipe
  
• 15 ft cable/cast iron counterweight assembly
  
• Two adjustable stop collars
  
• Stainless Steel Float
  

Switch ordered separately. See Product Selection.

Type	Style	Stainless Steel
		⋆	Cat. No.
1	A	A	840-5A1
4	A	A	840-5A4

⋆ See Float Size Table, Float Size Table.

Single Arm Lever, Separate Pulleys

A cable runs over two pulleys which are separate from the switch. The cable has a float fixed at one end and a counterweight at the other end. Adjustable stop collars on the cable move the switch operating lever.

Base-Mounted



Stainless Steel Operator Assemblies include the following:

• Two pulleys for separate mounting
  
• 15 ft cable/cast iron counterweight assembly
  
• Two adjustable stop collars
  
• Stainless Steel Float
  

Switch ordered separately. See Product Selection.

Type	Style	Stainless Steel
		⋆	Cat. No.
1	A, D, DS	A	840-3AD
	B	F	840-3BCE
4	A	A	840-3AD
	B	F	840-3BCE
7 & 9	A	A	840-3AD
	B	F	840-3BCE
⋆ See Float Size Table below.

Float Size Table

Type	Sphere Diameter	Elongated Sphere Diameter x Length
A	6 in.	—
F	—	7 in. x 12.5 in.
Note: Float size dimensions do not imply that Float Operator Assemblies can be interchanged.

Modifications

Ordering Modifications

Modifications are ordered by adding the appropriate modification suffix code to the catalog number of the float operator assembly. See the Modifications table below.

Additional Stainless Steel Cable
Description	Modification Suffix Code
For stainless steel assemblies, additional cable, longer than 15 ft., can be supplied factory installed. To order, add the suffix code at right followed by a number for the total amount of cable required. Example: Float Operator Assembly, Cat. No. 840-4A1 with five additional feet of stainless steel cable (20 ft. total) would become 840-4A1X920.	X9_

Accessories

Accessories are ordered as separate catalog numbers. Select the required accessories from the Accessories table below.

Additional Rod
Description	Cat. No.
Additional 3 ft. sections of stainless steel tubing can be supplied for Float Operator Assemblies. All necessary couplings are included.	840-N1

Standards and Certification

File and Guide Numbers
Bulletin 840	UL		CSA
	File Number	Guide Number	File Number	Class
	E14842 E53048 (Haz. Loc.)⋆	NKPZ, NKPZ7 NOWT	LR1234	3211-06
	Hazardous Location Enclosure not CE compliant.
⋆ Style A is listed for hazardous locations. Styles B, D, and DS are not.

• UL 508
  
• UL 698 (Haz. Loc.)
  
• UL 1604 (Haz. Loc.)
  

• CSA 22.2 No. 14
  
• NEMA ICS-2
  

Approximate Dimensions

Approximate Dimensions and Shipping Weights

Dimensions in inches (millimeters). Dimensions are not intended to be used for manufacturing purposes.

Type 1
Mounting Bracket

Style A —Approximate Shipping Weight 4 lbs (1.8 kg)

Style B —Approximate Shipping Weight 3 lbs (1.4 kg)

Styles D and DS —Approximate Shipping Weight 2 lbs (0.9 kg)

Type 4

Styles A and B —Approximate Shipping Weight 4 lbs (1.8 kg)