Specifications
Position. WFM-Series meters should be installed hori-
zontally with the register up. Vertical mounting will result in
some degree of under-measurement and shortened life of
the bearings. No upstream straight pipe is required.
Couplings. Male NPT threaded couplings are included
with each meter. The threads on the end of the meter are
IPS straight threads one size bigger than the meter size.
Though it is possible to thread a standard pipe coupling
directly onto the meter for close coupling, the included cou-
plings are much preferable because they provide a union
connection for meter service. Be sure to use the included
gasket between the end of the meter and the coupling.
Connections. WFMxx2 and WFMxx1 sensors are sup-
plied with a color coded output cable (see diagram, page
3). Optional connectors can be ordered to plug directly into
a Walchem controller or metering pump.
WARNING
DO NOT INSTALL
METER IN OVERHEAD
INDOOR PIPING OR
WHERE LEAKAGE
MAY CAUSE DAMAGE
GENERAL INFORMATION, INSTALLATION and MAINTENANCE
Page 2
GENERAL INFORMATION
WFM-Series meters use the internationally-accepted
multi-jet principle. A gear train drives the register totalizer
dials. For pulse output, one of the pointers is replaced by a
magnet arm, which is detected by an encapsulated sensor
attached to the outside of the lens.
WFMxx2 meters use a solid-state, long-lasting Hall-effect
sensor, which requires power. They are suited for use
with Walchem controllers and metering pumps that have
sensor power.
WFMxx1 meters use a reed switch. They provide a dry
contact closure and do not require power.
WFMxx0 meters do not have a sensor, and they totalize
only.
SPECIFICATIONS
6 mA at 12 Vdc (WFMxx2 only)
105˚ F (40˚ C) max
150 psi operating
Cast bronze, epoxy powder coated inside and out
Engineered thermoplastic
Alnico
+/- 1.5% of reading
WFMxx2 WFMxx1 WFMxx0
Hall-effect Reed switch Totalizer only
20 mA 20 mA n/a
24 Vdc 24 Vdc or Vac n/a
12’ (4 m) standard (2000’ maximum run)
3/4” 1” 1-1/2” 2”
0.22 0.44 0.88 1.98
22 52 88 132
Power
Temperature
Pressure
Materials Body
Internals
Magnet
Accuracy
Pulse Output
Sensor
Maximum Current
Maximum Voltage
Cable Length
Flow Rates (GPM)
Minimum
*Maximum
INSTALLATION
Pulse Output. Both WFMxx2 and WFMxx1 sensors respond to
a magnet that rotates on the face of the meter under
the lens. The sensor turns on and off once each time
the magnet passes under it. Sensors are designed for
electronic control loads, and should not be used to switch
power loads or line voltages. See maximum current and
voltage ratings, under Specications.
MAINTENANCE
Walchem recommends all service to be performed by an
authorized distributor or the factory to maintain the integrity
of the protective tamper-proof wire-and-seal.
Inlet Strainer. Clean the strainer yearly, or as required,
depending on water condition. Pull out the strainer or back-
ush the meter to loosen trapped particulates.
Calibration. Meters used for billing or billing exemp-
tion may be regulated by state or local authorities. New
meters are factory-tested to meet the AWWA C-708
Multi-Jet Meter accuracy specification. Some states
require retesting at various intervals, typically eight years
for 3/4" meters, six for 1", and four for 1-1/2" and 2". Meters
used for control should be tested every 5-10 years. Testing
can be done by the factory or local meter shops authorized
for this purpose.
Please contact Walchem before sending
meter in for calibration or servicing.
Changing Pulse Rates: See Page 3.
Internal Parts Replacement: See Page 4.
*CAUTION: Excessive flow can cause breakage. Do not exceed
recommended maximums.
Caution: These water meters
are not recommended for instal-
lation in uninsulated suspended
ceilings where freezing is pos-
sible, or in any overhead indoor
piping configuration where leak-
age may cause damage.