Pumptec 356U SERIES - Manual (Page 4)

4 Version 061113
Pumptec Operating Instructions and Parts Manual PUMP SERIES 348U | 350U | 356U
positive displacement pumps providing a specific amount of
fluid constantly while operating. This volume of fluid must
be directed out thru a nozzle or back to a tank because it
cannot be stopped completely without creating excessively
high pressure and risk of damage to pump, components,
property and person. It is recommended a safety device such
as a regulating valve be installed directly on pump head as
protection in case of a failure of another component. Pressure
switches can be used to automate pump operation, but they
must have a pressure regulating device installed as a safety
device.
Fluid can enter a pump either from a filtered tank or
pressurized fluid line.
It is common to use a tank with pumps that are mounted above
the pump. Filtration is important to maintain proper function
of the pump and system. The extent of filtration may be greater
based upon some uses such as misting with ultra-fine nozzles.
iNLEt CONDitiON CHECkLiSt
Inadequate inlet conditions can cause serious malfunctions in
the best designed pump. Surprisingly, the simplest of things
can cause the most severe problems or go unnoticed to the
unfamiliar or untrained eye. REVIEW THIS CHECKlIST bEFORE
OPERATIOn OF AnY SYSTEM. Remember, no two systems are
alike so there can be no OnE best way to setup a system. All
factors must be carefully considered.
iNLEt SUPPLy should exceed the maximum flow being
delivered by the pump to assure proper performance.
• Open inlet shut-off valve and turn on water supply to avoid
starving the pump. DO nOT RUn PUMP DRY.
• Avoid closed loop systems especially with high temperature,
ultra-high pressure or large flows. Conditions vary with
regulating/unloader valve.
• When using an inlet supply reservoir, size it to provide
adequate liquid to accommodate the maximum output of
the pump, generally a minimum of 6-10 times the gPM
(however, a combination of system factors can change this
requirement).
iNLEt LiNE SizE should be adequate to avoid starving the
pump
• line size must be a minimum of one size larger than the pump
inlet fitting. Avoid tees, 90-degree elbows or valves in the
inlet line of the pump to reduce the risk of flow restriction
and cavitations.
• The line MUSt be a FlEXIblE hose, nOT a rigid pipe, and
reinforced on SUCTIOn systems to avoid collapsing.
• The simpler the inlet plumbing the less the potential for
problems. Keep the length to a minimum, the number of
elbows and joints to a minimum (ideally no elbows) and the
inlet accessories to a minimum.
• Use pipe sealant to assure airtight, positive sealing pipe
joints.
iNLEt PrESSUrE should fall within the specifications of
the pump.
• High RPM, high temperatures, low vapor pressures or high
viscosity may increase acceleration loss of liquids.
• Optimum pump performance is obtained with +20 PSI (1.4
bAR) inlet pressure. With adequate inlet plumbing, most
pumps will perform with flooded suction.
• After prolonged storage, pump should be purged of air to
facilitate priming. Disconnect the discharge port to allow
liquid to pass through pump and measure flow.
ByPASS tO iNLEt – care should be exercised when
deciding the method of bypass from control valves. See Misting
on pages 4 and 5.
• It is recommended that the bypass be directed to a baffled
reservoir tank, with at least one baffle between the bypass
line and the inlet line to the pump.
• Although not recommended, bypass liquid may be returned
to the inlet line of the pump if the system is properly
designed to protect your pump.
• A low-pressure, flexible hose should be used from the bypass
connection to the inlet of the pump.
• Caution should be exercised to avoid undersizing the bypass
hose diameter and length.
• Check the pressure in the bypass line to avoid over-
pressurizing.
USiNg CHEmiCALS
Chemicals can be mixed into the fluid and it is necessary to
understand whether these chemicals will damage the pump or
other system components. Another way to put chemicals into
the fluid is with a downstream injector.
An injector works as a result of the difference of pressure
between the inlet side of injector and discharge side. In most
cases, the pressure on the discharge side cannot exceed 1/2
of the inlet pressure. For example, 1000 PSI into an injector
should allow up to 500-600 PSI spray pressure on discharge
side. There are dual-function nozzles that permit high pressure,
chemical free rinse and low pressure, chemical spray. These
are convenient for the operator and will not harm a properly
designed system.