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3

46-620 B73 & Series 75 Liquid Level Switche

s

3. Tighten set screw(s) at base of switch housing.

4. Unscrew and remove switch housing cover. The threads

have been lubricated to facilitate removal.

NOTE: For supply connections, use wire with a minimum rating of

+167° F (+75° C) as required by process conditions. Use a
minimum of 14 AWG wire for power and ground field wires. 

NOTE: Housing must be grounded via protective ground screw in the

base of the housing.

NOTE: On high temperature applications (above +250° F [+121° C] in

float chamber), high temperature wire should be used
between control and first junction box located in a cooler area.
On non-hazardous applications, flexible conduit may be used
between the control and the first junction box.

5. The switch terminals are located next to the conduit 

outlet to facilitate wiring. Bring supply wires through 
conduit outlet. Route extra wire around enclosing tube
under the baffle plate, and connect them to the proper 
terminals. Refer to the wiring diagram, 

Figure 3

, or your

switch bulletin for this information. 

NOTE: For models with Series HS or H1 switches with high tempera-

ture lead wire, the leads are routed out through the conduit
opening by the factory. A suitable conduit box should be
provided for the connection of the leads to the control wiring.

6. Dress wiring to ensure no interference or contact with tilt

of switch or replacement of switch housing cover.

Caution:

Observe all applicable electrical codes and proper wiring
procedures.

Caution:

In hazardous areas, do not power the unit until the conduit
is sealed and the enclosure cover is screwed down
securely.

7. Replace housing cover.

8. If control has been furnished with an explosion proof or

moisture proof (gasketed) switch housing, it must be
sealed at the conduit outlet with a suitable compound or
non-hardening sealant to prevent entrance of air.

9. Test switch action by varying liquid level in float chamber.

NOTE: If switch mechanism fails to function properly, check vertical

alignment of control housing and consult installation bulletin
for additional wiring information on switch mechanism
furnished. See 

Section 6.1.2, Switch and Housing

Reference

on page 19.

10. Check cover to base fit to be certain gasketed joint is tight.

A positive seal is necessary to prevent infiltration of mois-
ture laden air or corrosive gasses into switch housings.

Internal Circuit

(Right) Switch

1

2

3

Load

Load

Close on high level

Close on low level

Line

4

5

6

Internal Circuit

(Left) Switch

Load

Load

Close on high level

Close on low level

Line

Common

Common

Figure 3

Wiring Diagram

Summary of Contents for B75

Page 1: ...Sealed External Cage Liquid Level Switches B73 Series 75 Installation and Operating Manual...

Page 2: ...ardous Low Voltage Directive For use in Installation Category II Pollution Degree 2 If equipment is used in a manner not specified by manufacturer protection provided by equipment may be impaired Noti...

Page 3: ...What To Do 10 4 1 1 Keep Control Clean 10 4 1 2 Inspect Switch Mechanisms Terminals and Connections Monthly 11 4 1 3 Inspect Entire Unit Periodically 11 4 2 What To Avoid 11 5 0 Specifications 5 1 Age...

Page 4: ...necessary provide a stand or hanger to help support its weight All piping should be straight and free of low spots or pockets so that lower liquid line will drain towards the vessel and upper vapor li...

Page 5: ...of the two switch actuating level marks on the float chamber with the desired levels in the vessel 1 5 Wiring Caution Level controls are shipped from the factory with the enclosing tube tightened and...

Page 6: ...e factory A suitable conduit box should be provided for the connection of the leads to the control wiring 6 Dress wiring to ensure no interference or contact with tilt of switch or replacement of swit...

Page 7: ...t moves the magnetic attraction sleeve up within the enclosing tube and into the field of the switch mechanism magnet Refer to Figure 4 As a result the magnet is drawn in tightly to the enclosing tube...

Page 8: ...e lower actuation point and resets on the higher actuation point Widening the differential will allow the switch to trip on the original actuation point and reset at a later or higher point The differ...

Page 9: ...m nuts and guide washer on the stem in the position previously noted Tighten upper jam nuts securely Refer to Figure 7 NOTE Use a new enclosing tube gasket when reassembling enclos ing tube to the cha...

Page 10: ...s of a hollow stem The lower float attaches to the upper attraction sleeve with a solid stem that extends upward through the upper float and stem assembly 2 5 1 Installation Preventive Maintenance and...

Page 11: ...ective If a thorough inspection of these possible conditions fails to locate the trouble proceed next to a check of the control s switch mechanism 3 1 Check Switch Mechanism 1 Pull disconnect switch o...

Page 12: ...ough control is deactivated Close operating medium supply valve on controls equipped with pneumatic switch mechanisms 4 With liquid in chamber proceed to check level sensing action by removing switch...

Page 13: ...presentative for assistance A complete description of the trouble should be provided along with information concerning your piping and mounting arrangement plus a description of your operating sequenc...

Page 14: ...s furnished for service instructions 4 Level controls may sometimes be exposed to excessive heat or moisture Under such conditions insulation on electrical wiring may become brittle eventually breakin...

Page 15: ...switch housing cover off the control longer than necessary to make routine inspections 2 Never place a jumper wire across terminals to cut out the control If a jumper is necessary for test purposes b...

Page 16: ...56 24 62 12 21 5 56 25 43 2 44 3 50 216 66 548 294 141 625 310 141 646 62 89 P75 0 75 8 50 3 09 21 93 11 56 6 12 25 00 12 21 6 12 25 68 2 56 3 50 216 78 557 294 155 635 310 155 652 65 89 5 2 Physical...

Page 17: ...158 F F HL LL B D A C E Model B73 Side Side Flanges Model B73 Upper Side Bottom Flanges Model B73 Threaded and Socket Weld Upper Side Bottom Housing D E NEMA 1 4 70 5 00 119 127 NEMA 4X 7 9 5 93 3 87...

Page 18: ...1 22 2 10 151 84 442 235 159 515 251 159 532 30 53 B75 0 67 8 69 3 80 22 69 11 56 6 69 25 56 12 21 6 69 26 21 2 56 3 24 221 97 576 294 170 649 310 170 666 65 82 C75 0 55 2 72 3 44 69 87 F75 0 55 10 9...

Page 19: ...158 F F HL LL B D A C E Model B3 Side Side Flanges Model B73 Upper Side Bottom Flanges Model B73 Threaded and Socket Weld Upper Side Bottom Housing D E NEMA 1 4 70 5 00 119 127 NEMA 4X 7 9 5 93 3 87 G...

Page 20: ...ury E 2 42 683 Dry contact B C D 42 683 Hermetically sealed F 42 683 Hermetically sealed HS H1 42 694 Bleed type pneumatic J 42 685 Non bleed type pneumatic K 42 486 High temperature dry contact R 42...

Page 21: ...erence Housing base Switch mechanism on previous page for switch and housing bulletin furnished Attraction sleeve kit includes items 4 5 6 7 089 3409 009 089 3409 002 Enclosing tube models w electric...

Page 22: ...in Mercury A 3 42 683 Anti vibration mercury E 2 42 683 Dry contact B C D 42 683 Hermetically sealed F 42 683 Hermetically sealed HS H1 42 694 Bleed type pneumatic J 42 685 Non bleed type pneumatic K...

Page 23: ...2 486 High temperature dry contact R 42 799 6 3 3 Switch and Housing Reference Models B C G J L M Models F K N Housing cover See Section 6 3 3 Switch and Housing Reference Housing base Switch mechanis...

Page 24: ...275 28 20 B73 3 0 59 304 stainless steel chamber 316 stainless steel float 304 stainless steel trim B73 4 0 59 316 stainless steel chamber 316 stainless steel float 316 stainless steel trim MODEL NUMB...

Page 25: ...Class I Div 1 Groups C D Class I Div 1 Groups B C D ATEX Series A Mercury 20 to 450 29 to 232 SPDT AKP ANP AKT ANT AAC ABC AKQ ANQ AKS ANS AA9 AB9 DPDT Series B Snap 40 to 250 40 to 121 SPDT BKP BNP...

Page 26: ...00 1000 38 288 399 482 538 CARBON STEEL CHAMBER B75 0 67 0 71 n a 1000 870 716 357 138 69 60 49 25 10 C75 0 55 0 59 n a 500 435 400 357 138 34 30 28 25 10 F75 0 55 0 56 n a 1000 870 800 523 200 69 60...

Page 27: ...block 50 to 550 46 to 288 SPDT 1 HM3 HM4 HA9 HM3 HM4 HA9 DPDT 1 HM7 HM8 HB9 HM7 HM8 HB9 Series H1 Hermetically Sealed 1 amp Snap with wiring leads 50 to 750 46 to 399 SPDT 1 HKJ HKK n a HKJ HKK n a SP...

Page 28: ...ds the cause of the claim to be covered under the warranty If the trouble is the result of conditions beyond our con trol or is NOT covered by the warranty there will be charges for labor and the part...

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