Master Catalog — Gems Sensors & Controls - G-15

PISTON TYPE
Flow Settings, Air (Typical)

Pressure Drop - Typical

Dependent on operating line pressure. Examples of set point ranges at a given line
pressure are shown below.

FS-925 Series

Line
Pressure

FS-925

FS-926

Min.

Max.

Min.

Max.

5 PSIG (Minimum)

0.5 SCFM

10 SCFM

2 SCFH

15 SCFH

100 PSIG

1.5 SCFM

25 SCFM

7 SCFH

50 SCFH

PRESSURE DROP (PSID)

Actuation Point

Part No. 26919

3
Part No. 26917

2
1

Part No. 26914

Minimum 5 PSI line pressure required.
0
0.05

Gas Calibration
Water flow units should not be used for air/gas applications: Gas flow units have a
special dash-pot piston for reliable operation. Gas calibration is dependent upon line
pressure, switch orientation, and the specific type of gas. The calibrated flow set point
is subject to change with fluctuations in line pressure.

How To Order - Standard Models - Water Calibration

.75

1.0
1.5
2
FLOW RATE - GPM
Tests conducted with units in vertical position (lead wires up) with water at
+70°F (21°C).

FS-926 Series

FS-925 Series - General Purpose

PRESSURE DROP (PSID)

2.0

Specify Part Number based on desired housing material and flow setting.
Liquids other than water: Special calibration is available from GEMS for media other
than water. Please consult factory with your requirements, including housing material
(brass or stainless steel), flow media, operating pressure, flow set point and liquid
viscosity (SSU). A lot charge will be applied for special calibrations.
Gas flow: Consult factory for available calibrations. Specify: Housing material (brass
or stainless steel), gas type, mounting orientation, operating pressure and actuation
setting (SCFM or SCFH) and normal flow rate. A lot charge will be applied for special
calibrations.

Part No.
26938

1.5

Part No. 26941

Part No. 26944

1.0

0.5

100

150

200

250

300

350

400

FLOW RATE - cc/Min.
Tests conducted with units in vertical position (lead wires up) with water at
+70°F (21°C).

Brass

316 S.S.

0.10

26914

26926

0.25

26915

26927

0.50

26916

26928

0.75

26917

26929

1.00

26918

26930

1.50

26919

26931

FS-925 and FS-926 switches are U.L. Approved for
Class I, Division 2, Groups A, B, C, D hazardous
locations.
They are also available with FM-approved, explosionproof junction box for Class I, Division 1, Group
D hazardous locations. Units must be assembled
completely at GEMS.
U.L. Approved - File No. E183854

FS-926 Series - Low Flow

FLOW SWITCHES

Part Numbers

Flow Settings
GPM, ±10%

Standard Wiring Color Code

Flow Setting

Part Numbers

Wire Color

Terminal

cc/Min. ±10%

Equiv. GPM

Brass Material

316 S.S. Material

Orange

N.O.

.013

26938

26951

Black

Common

100

.025

26939

26952

Red

N.C.

150

.045

26941

26953

200

.055

26942

26954

250

.065

26943

26955

300

.075

26944

26956

Notes:
1. Flow settings are calibrated using water @ +70°F on increasing flow, with units in a vertical position
(lead wires up). Consult factory regarding special flow setting calibration.
2. Temperature changes will slightly affect the standard water or gas flow settings listed. Oil flow settings
will vary with viscosity.
3. Use of 50 micron filtration is recommended.
-- Stock Items.

FS-925/926 Series / p2of2 / 30-SEP-14

Visit www.GemsSensors.com for most current information.

G-15

Master Catalog — Gems Sensors & Controls

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