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DESCRIPTION
FLOJET Industrial Duplex II Pumps are designed for a wide range of
applications and are constructed from a selection of materials suit-
able for handling a broad range of chemicals. The Duplex II series
of diaphragm pumps are self-priming and can be run dry without
harm. They are intended for intermittent duty cycles but can be run
continuously for short periods of time. The higher the duty cycle the
shorter the expected life of the pump.
Typical pump uses are liquid transfer, spraying, cooling, circulation,
filtration and dispensing.
OPERATION
To start and prime the pump, the discharge line must be open al-
lowing trapped air to escape thus avoiding the potential of airlock.
The pressure switch will shut off the pump automatically when the
discharge valve is closed and the pressure has risen to the switch
OFF set point. The pressure switch will restart the pump when a
valve is opened and the discharge line pressure drops to the ON set
point of the pressure switch.
DEMAND OPERATION
(INTERMITTENT DUTY)
Demand Operation is considered an “intermittent duty” applica-
tion. The maximum intermittent duty cycle is that which will cause
the motor to reach its maximum thermal limits. Once the maxi-
mum thermal limit is reached, the motor must be allowed to settle
to a lower temperature ideally being ambient before resuming op-
eration. Running the pump at or near the maximum thermal limit
for extended period of time will shorten the life of the pump and
may result in immediate pump failure.
BYPASS OPERATION
(IF EQUIPPED)
Models equipped with an external bypass system are designed
to pump at high pressures while at low or high flow rates. Models
equipped with a bypass only will continue to run until the power is
manually turned off.
The Duplex II pumps are not recommended for continuous duty
service due to limited motor brush life. Operation at lower pres-
sures and temperatures, however, will extend overall pump service
life.
MOUNTING
The FLOJET Duplex II Series pumps are self-priming. Vertical prime
may vary depending on the fluid viscosity, suction tube size, foot
valve and pump configuration.
The pump should be mounted in a dry and adequately ventilated
area. If mounted within an enclosure, provisions to cool the motor
may be necessary.
HORIZONTAL
FLEXIBLE
HOSE
TYPICAL
VERTICAL
RIGID
PIPE
PREVENTATIVE MAINTENANCE TIPS
If pumping a liquid other than water the pump should be flushed
with water (if applicable) after each use.
Sealers and Teflon tape acting as a lubricant can cause cracked
housings or stripped threads due to over tightening. Care
should be used when applying sealers; the tape may enter the
When wiring electrically driven pumps, follow all electrical and
safety codes, as well as the most recent National Electrical Code
(NEC) and the Occupational Safety and Health Act (OSHA).
Make certain the power source conforms to the pump voltage. Be
sure all power is disconnected before installation.
The pump should be wired into an individual (dedicated) circuit,
controlled with an UL/C-UL certified double pole switch rated at or
above the fuse ampere indicated on the pump motor label.
On 115-volt AC pumps, the black wire lead is live or common, the
white lead wire is neutral and the green/yellow is ground. On 230-
volt AC pumps the brown wire lead is live or common, the blue wire
is neutral and the green/yellow is ground.
On 12 and 24 volt pumps the red lead is positive and should be
connected to the battery plus (+) terminal. The black lead is ground
and should be connected to the battery minus (-) terminal. Use T6
AWG wire minimum. Use a fuse to protect the system wiring and
components.
Improper duty cycle and/or rapid start stop conditions caused by
undersized spray nozzles will cause the internal thermal breaker
(if equipped) to trip, or can cause premature motor failure due to
excessive heat.
W A R N I N G
Risk of an electrical shock!
pump inhibiting valve action, causing no prime or no shut-off
conditions. Failures due to foreign debris are not covered under
warranty.
Before freezing conditions occur, the pump must be liquid free or
winterized with proper anti-freezing chemicals.
If mounting the pump in an outdoor environment the pump should
be shielded from water, dust, sunlight and wash down spray.
Do not assume chemical compatibility. If the fluid is improperly
matched to the pumps Elastomers, the pump may fail to prime,
have low pressures or the pressure switch may not shut off.
PLUMBING
Use flexible hose of the correct pressure rating that is compatible
with the fluid to be pumped. Tubing should be a minimum of 3/8”
(9.5 mm) ID and at least 20 inches (508 mm) in length to avoid ex-
cess stress on the pump ports. Do not crimp or kink the tubing. The
pump head maybe rotated in 90° increments to simplify plumbing.
FLOJET does not recommend the use of metal fittings, standard
plastic male and female threaded fittings can be acquired at com-
mercial plumbing supply stores. FLOJET also distributes plastic
barb fittings through our distributors (form no. F100-001).
The use of check valves in the plumbing system could interfere with
the priming ability of the pump. If a check valve is installed in the
plumbing it must have a cracking pressure of no more than 2 PSI
(.14 bar). Use of a minimum 40-mesh strainer or filter in the pump
inlet line will prevent foreign debris from entering the system. Fail-
ures due to foreign debris entering the pump will not be covered
under the limited warranty.
Note:
Inlet pressure must not exceed 30-PSI (2.1 bar) maximum.
