L91B1068/U

Product Description

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

• 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 in case back.

Table 1. Models available.

Models (Table 1):

L91A: Single potentiometer; nonadjustable proportioning range.

L91B: Single potentiometer; adjustable proportioning range.

L91D: Two potentiometers allow unison control of motors; adjustable proportioning range.

Electrical Rating: 24 Vac.

Potentiometer Action: Wiper moves toward W on pressure rise, toward B on pressure fall. Potentiometer is field replaceable.

Potentiometer Resistance: 140 ohms (nominal) for L91A, B, and D models.

Pressure Sensing Element: Brass bellows, 10-300 psi models phos-bronze bellows.

Minimum Ambient Temperature: 32° F (0° C)

Maximum Ambient Temperature: 150° F (66° C)

Adjustment Means: Screws on controller case top; knurled 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): Graduated from A to F with a MIN (minimum) value below A. (See Table 2 for the value of each division.)

Mounting Means: Fitting on bellows has 1/4 - 18 NPT threads (external on 0 to 16 oz/sq. in., 0 to 4 psi, and 0 to 15 psi models; internal on all other models) for mounting on a pipe or steam trap (siphon loop).

NOTE: Some models are available with 1/4 - 19 BSP-TR internal threads; see Table 1.

Also can be surface mounted by screws through two knockout holes in case back.

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.Order Guide

Table 2. Approximate value of each division (A to B, B to C, etc.) on proportioning (throttling) range scaleplate (L91B,D,F only)

BNSENS (Nanjing) Sensor Technology Co., Ltd. is located in Nanjing, China. It is a high-tech enterprise specializing in the development, manufacturing and trade of sensor products. The company has brought together a group of outstanding technical experts in various fields such as automation, electronics, machinery and computers. All employees of the company have college degrees or above. It adopts the world-class management and operation model and 6 sigma quality system. At present, the company's main products are pressure, liquid level, flow, current, switches, etc. The company's users are all over the country, and some products have been exported to Japan, South Korea and Southeast Asia.

Since its inception, the company has been based on the technical accumulation and management standards of American sensor giants. It is composed of senior engineers and managers who have served in multinational companies for many years, and has rapidly developed various pressure sensors, transmitters, liquid level, flow meters, pressure switches, digital meters, current sensors, proximity switches and other products. After years of unremitting efforts, it has become one of the leading suppliers in the domestic automation industry. Our pressure transmitters can achieve an accuracy of more than 3/10, 000. The products have been widely used in oil, natural gas, electricity, chemical industry, metallurgy, building materials, food, light industry, environmental protection, aerospace, tap water, municipal and other industries.

It is a sensor science and technology innovation company that masters the core technology of MEMS chips. The company has a research and development center in Minnesota, USA. The leader is Dr. Pan Hanjin, a famous scientist in the sensor industry. Dr. Pan Hanjin has been deeply involved in the sensor industry for more than 20 years and is an expert in the sensor industry.

The company has a number of ASIC chips independently developed, which are widely used in industrial, automotive, home appliance and other markets.

BNSENS (Nanjing) Sensing Technology Co., Ltd. is a strategic partner of Honeywell in China. The two parties proposed a plan of East serving East and jointly developed several sensors specifically for the Chinese market. These sensors will be widely used in intelligent manufacturing, Internet of Things, artificial intelligence, and smart home fields. These sensors include: Magnetic sensors, temperature sensors, humidity sensors, force sensors, fire water pressure sensors, equipment vibration sensors, human body status monitoring sensors, motion sensors, etc.

History of BNSENS Company:

BNSENS is a company focusing on sensors, instruments, and electronic components. We are a young company, founded in 1999, just 25 years old, and we are still growing.

1999: The company's first pressure sensor was launched, mainly for the petroleum and petrochemical industries.

2002: The company expanded its product line and launched temperature sensors

2005: Started producing high-precision pressure sensors for the test and measurement market

2006: Became an official authorized agent of Honeywell

2009: Introduced the Six Sigma management system, and the product qualification rate was greatly improved

2010: Became a supplier of Emerson

2011: We started selling SICK sensors

2014: Introduced the sensor production line from Germany, developed more industrial control sensors, and cooperated with TSMC

2015: Cooperated with Siemens in Vietnam

2017: The factory moved to Nanjing High-tech Zone

2019: Became a national high-tech enterprise in China

2023: We started selling products from Infineon and Rohm

BNSENS, The Future Starts Here.