Honeywell L91A Product Data Download Page 3

L91A,B,D PROPORTIONING PRESSURETROL

®

 CONTROLLERS

3

60-2152—08

Electrical Connections: 

Internal screw terminals. Hole inside 

of case for 1/2 in. conduit.

Dimensions: 

See Fig. 1; see Fig. 2 for mounting steam trap 

(siphon loop).

Weight: 

1 lb, 15 oz (0.88 kg).

Finish: 

Gray.

Replacement Parts:

129178 Thermoplastic Cover.

23176CB Potentiometer: For all L91A models and a few L91B 

models (see Table 1); 140 ohms (nominal); length of active 

winding is 7/64 in. (2.8 mm).

23176CF Potentiometer: For all L91D models and most L91B 

models (see Table 1); 140 ohms (nominal); length of active 

winding is 1/4 in. (6.4 mm).

Accessories:

50024585-001 Steam Trap (siphon loop): 1/4 in. brass pipe 

with 1/4 -18 NPT external threads on both ends.

14026 Steam Trap (siphon loop): 1/4 in. steel pipe with 1/4 -18 

NPT external threads on both ends.

33312B Knurled Adjustment Knob: With setscrew; fits on main 

scale pressure adjusting screw.

4074BWJ Limit Stop Assembly: To limit setpoint ranges; 

includes 129564 Range Stop 107194 Range Stop Screw, 

and 23466 Wrench.

Table 2. Approximate value of each division (A to B, B to C, etc.) on proportioning

(throttling) range scaleplate (L91B,D,F only)

Operating Range

 Value of Each Division

U.S. Customary Units

Metric Units

U.S. Customary 

Units

Metric Units

0 to 10 oz/sq in.

0 to 7 kPa

6.2 oz/ sq in.

2.7 kPa

0 to 15 psi

0 to 103 kPa

1.8 psi

12.4 kPa

5 to 150 psi (L91B)

0.03 to 1.03 MPa

7.8 psi

0.054 MPa

5 to 150 psi (L91D)

0.03 to 1.03 MPa

6.7 psi

0.046 MPa

10 to 300 psi (L91B with 7/64 in. potentiometer)

0.07 to 2.07 MPa

16.4 psi

0.113 MPa

10 to 300 psi (L91B,D with 1/4 in. potentiometer) 0.07 to 2.07 MPa

13.8 psi

0.095 MPa

Summary of Contents for L91A

Page 1: ...iphon loop is recommended Wiper on controller potentiometer moves in response to pressure changes L91D has two potentiometers for unison control of two motors L91B D models have adjustable proportioning throttling range to allow selection of desired pressure control range Adjustments made with screws on case top Large easily read scaleplates in both U S customary oz sq in psi or in Hg and metric k...

Page 2: ...rled knob for main scale setting on 10 to 300 psi 0 07 to 2 07 MPa models Setpoint At low pressure end of proportioning throttling range Main Scaleplate Marked in both U S customary oz sq in psi or in Hg and metric kPa MPa or mm Hg units Proportioning Range Scaleplate L91B D only Gradu ated from A to F with a MIN minimum value below A See Table 2 for the value of each division Mounting Means Fitti...

Page 3: ...6 Steam Trap siphon loop 1 4 in steel pipe with 1 4 18 NPT external threads on both ends 33312B Knurled Adjustment Knob With setscrew fits on main scale pressure adjusting screw 4074BWJ Limit Stop Assembly To limit setpoint ranges includes 129564 Range Stop 107194 Range Stop Screw and 23466 Wrench Table 2 Approximate value of each division A to B B to C etc on proportioning throttling range scalep...

Page 4: ...RE ALSO AVAILABLE WITH 1 4 19 BSP TR INTERNAL THREADS SEE TABLE 1 PROPORTIONING RANGE ADJUSTING SCREW ON L91B D MODELS ONLY 33312B KNURLED ADJUSTMENT SCREW KNOB 7 8 IN 22 2 MM DIAMETER KNOB IS INCLUDED WITH 10 TO 300 PSI 0 07 TO 07 MPa MODELS OPTIONAL ACCESSORY FOR OTHER MODELS FOR 10 TO 300 PSI 0 07 TO 2 07 MPa MODELS DIM C INCLUDES THE KNURLED ADJUSTMENT KNOB TABULATION OF DIMENSIONS A B AND C O...

Page 5: ...ns in accordance with approved standards Use only a small amount of pipe compound to seal the connection joints Excess pipe compound may clog the small hole in the fitting and prevent the controller from operating properly To avoid leaks and damage to the case use a parallel jaw wrench on the controller fitting Do not tighten the controller by hand by holding onto the case and turning it Fig 2 App...

Page 6: ...ain Scale Set Point All models Adjust the main scale setpoint for the desired operating pressure by turning the main scale adjusting screw Fig 7 or knurled adjustment knob on 10 to 300 psi 0 07 to 2 07 MPa models on the top of the case until the main scale setting indicator is at the minimum pressure desired The proportioning range extends above this value The scaleplate is marked in both customar...

Page 7: ...nced that is equal the relay contacts are open When the circuit is balanced the motor or actuator does not run If the pressure of the medium rises the wiper in the controller moves toward W This unbalances the circuit so a larger current flows through one side of the balancing relay The close contacts in the relay make causing the motor or valve actuator to drive toward its closed position As the ...

Page 8: ...e controller The ohmmeter should read about 135 ohms for an L91A B or D 5 Connecting the ohmmeter between controller terminals W and R Fig 8 and raising the setpoint of the controller above the actual pressure being measured The ohmme ter should read the full value of the potentiometer mea sured in step 4 135 ohms for an L91A B or D 6 Slowly lowering the setpoint of the controller while observing ...

Page 9: ... the wiper arm and not to change the wiper tension Any damage or change in tension will decrease the life of the new potentiometer 1 Disconnect all power to the controller 2 Loosen the cover screw below the main scaleplate and remove the cover 3 Mark the wires to the external device motor or valve actuator and disconnect them from the terminal block 4 Remove the screw holding the terminal block br...

Page 10: ...A 0 4 6 2 1 3 4 5 16 14 12 10 8 0 kPa OZS IN 2 DIFF IS ADDITIVE 2 6 7 M8547A BARE WIRES ENAMEL REMOVED TERMINAL BLOCK R W B POTENTIOMETER WIRES WIPER ARM BOLT POTENTIOMETER ACTIVE WINDING POTENTIOMETER BRACKET 1 1 2 2 THE POTENTIOMETER IN AN L91A IS MOUNTED AT A 45 DEGREE ANGLE INSTEAD OF HORIZONTALLY AN L91D HAS TWO POTENTIOMETERS TERMINALS ARE LABELED DIFF MAIN MIN B D F E C A 0 4 6 2 1 3 4 5 16...

Page 11: ...L91A B D PROPORTIONING PRESSURETROL CONTROLLERS 11 60 2152 08 ...

Page 12: ...ons Honeywell International Inc 1985 Douglas Drive North Golden Valley MN 55422 Honeywell Limited Honeywell Limitée 35 Dynamic Drive Toronto Ontario M1V 4Z9 customer honeywell com U S Registered Trademark 2009 Honeywell International Inc 60 2152 08 K K Rev 12 09 Printed in U S A ...

Reviews: