Series F7 Liquid Level Switches
C
B
EXTERNALLY
WELDED FLANGE
PIPE
ELBOW
PIPE
13/16 [20.62]
3-15/32 [88/09]
13/16 [20.62]
SWITCH CLOSED POSITION
POSITION
]
13/16 MIN
LEAD WIRES
A
1-7/32 MAX
[29.2]
Specications - Installation and Operating Instructions
Bulletin E-75
SWITCH ACTION (Normally open/Normally closed)
Vertical Models
Vertical mount models are shipped with normally open switch contacts which close as
the oat rises toward the mounting threads. Reverse switch action by removing the
oat, rotating it end-for-end and replacing it on the stem.
Horizontal Models
Contacts in horizontal models F7-HPS-1 (internal mount) and F7-HPS-2 (external
mount), are normally open when the oat is down and normally closed when the oat
is up. Models F7-HPS-1 and -2 also have indicating arrows on the stem end to conrm
oat alignment. See installation notes on reverse. Horizontal model F7-HSS is in the
normally open position when the indicating arrow points up, and normally closed when
the arrow points down.
INSTALLATION
Choose a location away from ll pipes, drains, or other areas where turbulence or
wave motion might occur. Turbulence will cause false actuations and shorten contact
life. Excess contaminants in uid may inhibit oat operation and occasional wipe-down
may be necessary. Care should be taken that switches are always operated within
electrical ratings. Read and understand all safety precautions on back of this sheet
before installing.
MOUNTING
Install vertical mount models in an appropriate 1/8˝ NPT tting. Vertical models
mount internally, oriented within 30° of vertical, or select optional ttings for external
mounting. Model F7-HPS-1 must be mounted internally, which means the switch must
be secured to the wall of the tank or vessel from the inside. Install horizontal model
F7-HPS-1 in a 5/8˝ (16 mm) hole and secure with nut provided. Tank wall should
not exceed 1/8˝ (3 mm). Model F7-HPS-2 requires a horizontal 1/2˝ NPT(F) tting
and can be tted to the tank or vessel from the outside. Model F7-HSS requires a
horizontal 1/2˝ NPT(F) tting and can be mounting from the inside or outside (internally
or externally) of the tank or vessel.
DWYER INSTRUMENTS, LLC
P.O. BOX 373 • MICHIGAN CITY, INDIANA 46360, U.S.A.
F7-SB
Dimensions, Inches [mm]
Model
F7-SB
F7-SS2
F7-PP
F7-BT
F7-MPP
(A) Stem
Length
2.75 [70]
2.06 [52]
2.18 [55]
2.18 [55]
1.63 [41]
(B) Float
Diameter
1.13 [29]
1.0 [25]
1.18 [30]
1.18 [30]
0.63 [16]
(C) Float
Height
1.38 [35]
1.0 [25]
1.0 [25]
1.0 [25]
0.63 [16]
(D) Actuation
from HEX
1.0 [26]
0.73 [19]
0.69 [18]
0.69 [18]
0.47 [12]
FITTING
COUPLING
D
2-23/64 [59.92]
MAX
40∞ MAX
1-19/32
[40.46]
F7-HPS-2, EXTERNAL HORIZONTAL MOUNT F7-HPS-2, INTERNAL HORIZONTAL MOUNT
2 [50.80]
SPECIFICATIONS
Electrical Rating (Maximum): F7-SB, SS2: Power: 50 W any combination of V and
A not to exceed 200 V (DC or AC peak) or 1.5 A (DC or AC peak); F7-PP, BT, HSS:
AC: 30 VA, 0.14 A @ 200 V; DC: 0.28 A @ 24 V, 0.07 A @ 120 V. F7-MPP: 10 VA,
0.1 A @ 120 VAC; F7-MPP-NO: 50 VA, 0.2 A @ 240 VAC; F7-HPS: 15 VA, 1 A @
220 VAC/DC.
Mounting Connections: 1/8˝ NPT(M) (all vertical mount), 1/2˝ NPT(M) (F7-HPS-2,
F7-HSS), M16 x 2 (F7-HPS-1).
Wire Leads: F7-SB, SS2, PP, BT: 22 AWG x 18˝ (46 cm); F7-MPP, HSS: 22 AWG x
24˝ (61 cm); F7-HPS: 22 AWG x 39˝ (1 m).
Enclosure Rating: F7-HSS: Explosion-proof, Class I, Groups A, B, C, D; Class II,
Groups E, F, G; Class III.
Weight: F7-SB, 2 oz. (58 g); F7-SS2, 1.2 oz. (34 g); F7-PP, 0.8 oz. (23 g); F7-BT,
0.7 oz. (20 g); F7-HPS-1, 1.5 oz. (43 g); F7-HPS-2, 2 oz. (57 g); F7-HSS, 3 oz. (94
g); F7-MPP, 0.8 oz. (23 g).
MODEL CHART
Model
Vertical Mount
F7-SB
F7-SS2
F7-PP
F7-BT
F7-MPP
Horizontal Mount
F7-HPS
-1, -2
F7-HSS
*PBT - Polybutylene Terephthalate
Optional Fittings (for Exterior Mounting of Vertical Models)
A-347, 1/8˝ x 1-1/4˝ NPT C.S. adapter.
A-347-SS, 1/8˝ x 1-1/4˝ NPT 316 SS adapter.
A-348, 1/8˝ x 1-1/2˝ NPT C.S. adapter.
A-348-SS, 1/8˝ x 1-1/2˝ NPT 316 SS adapter.
CENTERLINE
A
APPROXIMATE
CTUATION LEVEL
3-7/16 [87.29]
1/2 NPT
SWITCH OPEN
Material
Float/Stem
Buna-N and Epoxy/316 SS
316 SS (CYC)/316 SS
Polypropylene and
Epoxy/Polypropylene
Buna-N and Epoxy/PBT*
Polypropylene /
Polypropylene
Polysulfone/
Polysulfone
316 SS/316 SS
Phone: 219-879-8000
Fax: 219-872-9057
3/32
[2.54]
3/4
[19.05
[31.0]
1-5/32 MAX
DIA. MAX.
1-33/64
[38.48]
4-5/8 MAX
[116.8]
F7-HSS
40∞ MAX
Max
Temp.
220°F
105°C
300°F
149°C
220°F
105°C
220°F
105°C
176°F
80°C
185°F
85°C
392°F
200°C
www.dwyer-inst.com
e-mail: info@dwyermail.com
[20.6]
2-15/64 [56.74]
SWITCH CLOSED
POSITION
Max
Press.
150 psig
10 bar
450 psig
31 bar
100 psig
6.89 bar
150 psig
10 bar
100 psig
6.89 bar
150 psig
10 bar
300 psig
20.7 bar
Min
S.G.
0.60
0.75
0.60
0.45
0.90
0.85
0.60
1/2-14 NPT
M16X2
SWITCH OPEN
POSITION
Approx.
Deadband
1/16˝
2 mm
1/16˝
2 mm
1/8˝
4 mm
1/8˝
4 mm
1/8˝
4 mm
3/16˝
5 mm
1/8˝
4 mm
22 AWG
Installation notes - Do not subject reed
Gasket seal for internal
ficient
hand-tight plus one half turn.
Do not exceed 1.5 pounds/
may cause premature switch
wiring entering the device is
or humidity condensate.
switch controls to excessive shock or
vibration or any of the following:
• Bending or placing force loads on
reed switch housing.
• Over-torquing ttings on reed switch
housing.
• Placing pull-out force on lead wires.
foot (2 n/m) tightening
torque. Excessive torque
element or housing failure.
Indicating arrows are
provided on the stem
ends to confirm float
alignment.
mounting units should be
preassembled before
insertion through tank wall.
Wall thickness should not
exceed 1/8˝ (3 mm).
When preparing wires for
termination, avoid pulling
against the resin seal or
end plug of the float switch.
Avoid installations where
submerged or exposed to
excessive amounts of liquid
Units with tapered pipe
threads should be treated
with Teflon based thread
compound or tape before
insertion in fitting. Suf
torque is achieved at
CIRCUIT INFORMATION FOR REED SWITCH PROTECTION
Read information below before installing your new reed switch control!
Exceeding the current capacity of this Reed Switch control may cause FAULTY OPERATION! Be aware of the inductive and capacitive or lamp loads you may be placing on you
Reed Switch Control. The circuits below outline possible solutions to preventing overloads due to inrush or surge currents exceeding maximum or when the switch current and
product of the inductive back EMF exceed the switch’s power rating. Also the circuit for prevention of overload when switching lament lamps (low “cold” resistance) is outlined
below. Failure to follow these measures to protect Reed Switch Contacts may cause the contacts to weld together or result in premature wear.
Possible Circuit Solutions Indicated by Dashed Lines
RC SUPPRESSION
2
SWITCH
C
10
R
(1+50/E)
10*I
R
SWITCH
[uf]
C
Inductive loads
Possible causes -
An electromagnetic relay,
electromagnetic solenoid,
electromagnetic counter with
inductive component as circuit load.
DIODE SUPPRESSION
DIODE
PIV DIODE > V
INDUCTIVE
LOAD
REED
SWITCH
VARISTER PROTECTION
INDUCTIVE
LOAD
REED
SWITCH
VARISTER
USED IN
AC CIRCUITS
INDUCTIVE
LOAD
REED
SWITCH
Capacitive loads
Possible causes -
A capacitor connected in series or
parallel with Reed Switch control.
In a closed circuit, a cable length
(usually greater than 50m [162.5 ft.])
used to connect reed switch may
also introduce static capacitance.
Lamp loads
Possible causes -
A tungsten lament lamp load.
SURGE LIMITER FOR
CAPACITANCE IN SERIES
+V
L =0.5~5 mH
P
R
A
L
P
C
REED
LOAD
SWITCH
CURRENT LIMITING RESISTOR
IN SERIES
+V R
L
V-0.12 R
R
2
SWITCH
RESISTOR PROTECTION
FOR CAPACITIVE LOAD
+V
R = 50~500 Ohms
R
REED
SWITCH
A
R
B
C
LOAD
R
CURRENT LIMITING RESISTOR
R
L
SWITCH
REED
SWITCH
+V R
5R > R
INDUCTIVE PROTECTION FOR
CABLE LENGTH CAPACITANCE
LOAD
CABLE LENGTH
OVER 50 METERS
IN PARALLEL
L
L
R
L
P
L = 0.5~5 mH
P
[162.5 FT]
REED
SWITCH
REED
SWITCH
DWYER INSTRUMENTS, LLC
P.O. BOX 373 • MICHIGAN CITY, INDIANA 46360, U.S.A.
Printed in U.S.A. 4/23 FR# 440677-00 Rev. 6©Copyright 2023 Dwyer Instruments, LLC
Phone: 219-879-8000
Fax: 219-872-9057
www.dwyer-inst.com
e-mail: info@dwyermail.com
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