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L91A,B,D PROPORTIONING PRESSURETROL® CONTROLLERS
360-2152—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