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9100 Series

Heavy Duty Capacitive Liquid Level Switch for Water Based Fluids

9100 Image


The 9100 Series Heavy Duty Capacitive Liquid Level Switches are designed for detecting the presence of water, engine & system coolants that are compatible with Brass, Fluoropolymer and Fluoroelastomer materials. Ideal for use in many applications such as construction equipment, marine (boats/vessels), farm machinery, generators, liquid storage tanks, locomotive compressor condensate and boilers.

General Information & Features

State-of-the-art electronic switch circuitry is designed to give an alarm signal if the fluid falls below a preset level. All models have solid-state operation, no moving parts, and a built-in delay circuit (5 seconds) to avoid false alarms. The model 9100 is ideal for replacing mechanically operated switches in applications where system shutdowns or early warnings might be caused by fluid turbulence or vibration.

The model 9100 series switch is best suited for horizontal mounting at the level where the control signal or alarm is to be activated. Contact Rochester Gauges Customer Service for optional mounting locations.


Data Sheet

General Specifications*



Supply Voltage

7-32 VDC

Supply Current

5 mA

Maximum Load Current

100 mA @ 20°C

Alarm Delay Time

5 seconds

Maximum Pressure on Face

350 PSI

Operating Temperature Ranges

-40°C to 125°C


Internal - 350 PSI [2.5 MPa]
External - 5 PSI [35kP]


6.4G, 40Hz, 100 Hrs


3.5 oz, 99.5 g

Output Switch Positions

(See chart)

Materials of Construction*


SAE J1128 Type GXL, #18 (item 1)

Body Cover

Valox, glass reinforced (item 2)


Brass (item 3)

EMI Shield

Brass (item 4)

Probe Cover

Fluoropolymer (item 5)

Seals (Internal)


Thread Option Switch Positions Switch Delay Time
1/4" - 18 NPTF Closed in Air
Open in Fluid
5 Seconds
M18 - 1.5 Closed in Air
Open in Fluid
5 Seconds


*Materials and specifications are subject to change without notice. Pressure ratings subject to change due to temperature and other environmental considerations.