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L91A,B,D Proportioning
®
Pressuretrol Controllers
PRODUCT DATA
FEATURES
• Models available for pressure systems up to 300 psi
(2068 kPa).
• May be used with steam, air, noncombustible gases, or
other fluids noncorrosive to brass or phos-bronze (300
psi model) bellows.
• When used with steam boilers, a steam trap (siphon
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 mo
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® L91A,B,D PROPORTIONING PRESSURETROL CONTROLLERS SPECIFICATIONS Table 1. Models available. Maximum Surge a Operating Ranges Proportioning (Throttling) Range at Midscale Pressure U. S. U. S. Potentiometer Customary Customary b Model Units Metric Units Part No. Adjustable Units Metric Units psi kPa L91A 0 to 15 psi 0 to 103 kPa 23176CB No 0.5 psi 3.4 kPa 25 172 5 to 150 psi 0.03 to 1.03 MPa 23176CB No 5 psi 0.03 MPa 225 1551 b 0.07 to 2.07 MPa 23176CB No 12 psi 0.08 MPa 350 2413 10 to 300 psi
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® L91A,B,D PROPORTIONING PRESSURETROL CONTROLLERS Electrical Connections: Internal screw terminals. Hole inside 23176CF Potentiometer: For all L91D models and most L91B of case for 1/2 in. conduit. models (see Table 1); 140 ohms (nominal); length of active winding is 1/4 in. (6.4 mm). Dimensions: See Fig. 1; see Fig. 2 for mounting steam trap (siphon loop). Accessories: 50024585-001 Steam Trap (siphon loop): 1/4 in. brass pipe Weight: 1 lb, 15 oz (0.88 kg). with 1/4 -18 NPT external threads
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® L91A,B,D PROPORTIONING PRESSURETROL CONTROLLERS 4-1/2 (114.3) (COVER) L91A,B,D (110.3) (CASE) 4-11/32 2-3/4 (69.9) (98.8) 3-57/64 3-13/32 (86.5) 1-3/16 (30.2) 1-5/32 (29.4) 3 4 1-1/16 (27.0) 2 2 3-23/32 1-3/32 (27.8) (94.5) 3-7/8 2-5/64 (98.4) (52.8) ALL OTHER DIM C (SEE MODELS 7/8 1-13/16 TABULATION (22.2) (2) (46.0) TABLE) 13/16 10 TO 300 PSI (20.1) 0 TO 15 PSI 2 0 TO 16 OZ/IN 1/4-18 NPT 1 1-1/16 2-1/8 (53.5) (27.0) DIM A (SEE TABULATION TABLE)
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® L91A,B,D PROPORTIONING PRESSURETROL CONTROLLERS INSTALLATION When Installing This Product... L91 1. Read these instructions carefully. Failure to follow them PRESSURETROL could damage the product or cause a hazardous CONTROLLER condition. 2. Check the ratings given in the instructions and on the product to make sure the product is suitable for your PRESSURE GAUGE application. 3. Installer must be a trained, experienced service PRESSURETOL technician. 4. After installation is complete, check
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® L91A,B,D PROPORTIONING PRESSURETROL CONTROLLERS 6. Refer to Fig. 4 for typical hookup. W and B connections may be interchanged at the motor for reverse action ACTION ON (cooling). Follow the burner or boiler manufacturer’s PRESSURE FALL wiring diagram if provided. Also refer to the wiring WB diagrams in the motor instructions. 7. Replace the front cover when wiring is completed. R 1 W SERIES 90 L91 PROPORTIONING MODULATING MOTOR CONTROLLER B M9484 CLOSED R W1 M9494 (LOW FIRE) 1 W R1 OPEN
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® L91A,B,D PROPORTIONING PRESSURETROL CONTROLLERS point). The L91B settings provide system modulation between 70 and 75 psi or between 75 and 80 psi, depending on the MAIN SCALE PROPORTIONING RANGE exact setting of the L91B main scale setpoint. ADJUSTING ADJUSTING SCREW (L91B,D ONLY) SCREW CONTROLLER Due to device tolerances, the scaleplate settings are POTENTIOMETER 1 approximate and, therefore, the settings should be fine-tuned with the system operating. WIPER ARM(S) Proportioning Range (
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® L91A,B,D PROPORTIONING PRESSURETROL CONTROLLERS CHECKOUT MAIN SCALE PROPOTIONING ADJUSTING SCREW RANGE ADJUSTING After the controller is installed, wired, and set, it should be SCREW 1 tested with the system in operation. First, allow the system to (L91B,D ONLY) stabilize. Then, observe the operation of the controller while raising and lowering its setpoint. Pressure should increase when the setpoint is raised and decrease when the setpoint is lowered. Use accurate pressure testing equipm
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® L91A,B,D PROPORTIONING PRESSURETROL CONTROLLERS Replacing the Controller SERVICE INFORMATION Potentiometer (Fig. 8–10) IMPORTANT: CAUTION 1. Replace the controller potentiometer only when nec- Electrical Shock Hazard essary to obtain proper operation. 1. Only qualified service technicians should attempt to 2. When replacing the potentiometer, be very careful not service or repair flame safeguard controls and to bend or damage the wiper arm, and not to change burner systems. the wiper tens
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® L91A,B,D PROPORTIONING PRESSURETROL CONTROLLERS REMOVE BRACKET SCREW FROM TOP OF CASE TERMINAL MAIN DIFF. TERMINAL 16 7 BLOCK F 14 BLOCK 6 BRACKET E 12 5 BRACKET MAIN DIFF. 10 D 4 16 7 8 C 3 F 14 6 6 B 2 12 E 4 5 A 1 TERMINAL 10 D 2 4 MIN 8 0 0 R C BLOCK 3 6 kPa B OZS 2 DIFF. IS W 4 2 TERMINAL A IN ADDITIVE 2 1 MIN BLOCK B 0 0 kPa OZS DIFF. IS 2 IN ADDITIVE FIT HOLE IN BOTTOM OF BRACKET OVER SCREW PROTRUDING UPWARD M8521A FROM BOTTOM OF CASE M8548A Fig. 8. Removing terminal block bracket
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® L91A,B,D PROPORTIONING PRESSURETROL CONTROLLERS 11 60-2152—08
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® L91A,B,D PROPORTIONING PRESSURETROL CONTROLLERS Automation and Control Solutions Honeywell International Inc. 1985 Douglas Drive North Golden Valley, MN 55422 Honeywell Limited-Honeywell Limitée 35 Dynamic Drive ® U.S. Registered Trademark Toronto, Ontario M1V 4Z9 © 2009 Honeywell International Inc. 60-2152-—08 K.K. Rev. 12-09 customer.honeywell.com Printed in U.S.A.
