
Series LFM In-Line and Panel Mount Flowmeter
Specifications - Installation and Operating Instructions
Bulletin V-31
The Series LFM In-Line Flowmeter measures the flow of water and
other compatible media. Models possess dual GPM and LPM scales.
Various size ranges and connections are available to satisfy your application.
INSTALLATION
1. Select an indoor (only) location that is free from excess vibration,
within the specified temperature limits, and away from direct sunlight.
2. Handle carefully. Hand-tighten flange nut connection rings.
O-Rings will seal if hand tightened only. Do not overtighten the adapters
and fittings.
3. Install the flowmeter in an exact vertical plane, one that is in proper
alignment with the existing plumbing. Use wall or other structural supports at the top and bottom of the unit. Do not allow the instrument to
support the weight of pipes or tubing.
4. Use plumbers tape thread sealant. Do not use pipe dope compounds,
which can craze and crack housing. Hand tighten system pipe fitting to
adapter fitting. If additional torque is needed to seal pipe joint, use strap
wrench on adapter fitting.
5. If using solvent-based glues like PVC cement, in the piping system,
do so with the meter’s body removed until glue has cured, then purge the
system before re-installing. Do not solder brass fittings with the body
installed, because the heat generated to solder the brass fittings will
damage the flowmeter.
CAUTION: Ball valves and solenoid valves can have a “water cannon”
effect on opening, creating pressure that exceeds the warrantied ratings
and will damage the flowmeter.
Model
LFMA
LFMB
LFMC
LFMD
LFME
LFMF
SPECIFICATIONS
Service: Compatible liquids.
Wetted Materials: See chart.
Temperature Limits: See chart. Varies with pressure.
Pressure Limit: See chart. Varies with temperature.
Accuracy: ±5% full scale.
Process Connections: Various male and female NPT, metric union
connectors, and 90° male NPT elbow fittings available depending on
model series.
OPERATION AND MAINTENANCE
Once installed, the Series LFM In-Line and Panel Mount Flowmeter is
self-operating and requires no maintenance other than an occasional
cleaning with mild soap and a bottle brush. For this purpose, the unit
has been designed so that its body can be removed quickly and easily
while leaving all fittings intact.
When removing float for cleaning, note the floats “up” position. The float
is a precision part and must be reassembled without adverse treatment,
i.e. dropping, denting, and surface abrasion.
A
3-15/16
(100.01)
6-5/16
(160.34)
5-9/32
(134.14)
6-45/64
(170.26)
8-55/64
(225.03)
11-27/64
(290.12)
B
ø1-21/32
(ø42.07)
ø1-63/64
(ø50.40)
ø1-63/64
(ø50.40)
ø2-21/64
(ø59.13)
ø2-27/32
(ø72.23)
ø3-15/16
(ø100.01)
C
6-45/64
(170.26)
8-55/64
(225.03)
8-9/32
(210.34)
9-27/32
(250.03)
12-19/64
(312.34)
15-3/4
(400.05)
D
8-55/64
(225.03)
7-11/16
(195.26)
10-41/64
(270.27)
12-51/64
(325.04)
E
63/64
(25)
63/64
(25)
63/64
(25)
1-15/64
(31.35)
2-15/64
(56.75)
2-15/64
(56.75)
51/64
(20.24)
63/64
(25)
F
NPT
1/2 NPT
1/2 NPT
1/2 NPT
3/4 NPT
1 NPT
2 NPT
The standard technique for reading a Variable Area Flowmeter is to
locate the of greatest or widest diameter on the float, and then align that
with the theoretical center of the scale graduation. In the event that the
float is not aligned with a grad, an extrapolation of the float location must
be made by the operator as to its location between the two closest grads.
DWYER INSTRUMENTS,
INC.
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www.GlobalTestSupply.com

Temperature
212°F (100°C)
194°F (90°C)
176°F (80°C)
158°F (70°C)
140°F (60°C)
122°F (50°C)
104°F (40°C)
86°F (30°C)
68°F (20°C)
50°F (10°C)
Model
Polycarbonate
LFMA
Polycarbonate
LFMB
Polycarbonate
LFMC
Polycarbonate
LFMD
Polycarbonate
LFME
Polycarbonate
LFMF
0
0
Body
Flowmeter Temp. vs. Pressure Chart
29
(2)
Flange
Nut
ABS
ABS
ABS
ABS
ABS
ABS
58
(4)
Pressure
PSI (Bar)
Polypropylene
Polypropylene
Polypropylene
87
(6)
Float
Stop
ABS
ABS
ABS
116
(8)
Temperature
212°F (100°C)
194°F (90°C)
176°F (80°C)
158°F (70°C)
140°F (60°C)
122°F (50°C)
104°F (40°C)
145
(10)
Wetted Materials vs. Series
Float
S.S.316
S.S.316
S.S.316
S.S.316
S.S.316
S.S.316
O’ring
Fluoroelastomer
Fluoroelastomer
Fluoroelastomer
Fluoroelastomer
Fluoroelastomer
Fluoroelastomer
86°F (30°C)
68°F (20°C)
50°F (10°C)
Female
Thread
PA66 (nylon)
PA66 (nylon)
PA66 (nylon)
Temperature vs. Pressure
Chart when using PVC elbow fittings
0
0
/
/
/
29
(2)
PA66 (nylon)
PA66 (nylon)
PA66 (nylon)
Male
Thread
ABS
ABS
ABS
58
(4)
Pressure
PSI (Bar)
87
(6)
90 Male
NPT Elbow
PVC
PVC
PVC
PVC
PVC
/
116
(8)
145
(10)
Metric
Union
ABS
ABS
ABS
PVC
PVC
ABS
©Copyright 2014 Dwyer Instruments, Inc. Printed in U.S.A. 9/14 FR# R4-443531-00 Rev. 1
DWYER INSTRUMENTS,
INC.
Find Quality Products Online at: sales@GlobalTestSupply.com
www.GlobalTestSupply.com