Pressure Switches & Gauges

PressureTrol® Pressure monitoring modulating controllers L91A, B

L91 Proportioning Pressuretrol® Controllers are Series 90 Modulating Pressure Controllers that provide direct control of modulating motors or valves used on automatic burners or steam heating systems.

Features & Benefits: • 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 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 (kPa, MPa, or mm Hg) units. • Steel case with clear plastic cover to observe pressure settings and potentiometer action. • Fitting with 1/4 -18 NPT threads allows rapid installation. • Surface mount with screws through knockout holes back of casing