About Jet Pumps
A well jet pump is a non-submersible, non-self-priming,
centrifugal type pump which draws water from a water well, pond, lake, underground tank
or similar source of clean water. The pump operates by creating a pressure differential
with the help of jet ejector (JE) kit, comprised of a nozzle and venturi in a manner
similar to the turbines of a jet aircraft.
A jet pump comes with a pressure switch with (in most instances) adjustable On/Off
settings. Typical factory pressure switch settings (On/Off) are 20/40 or 30/50 psi. When
water pressure in the system falls below the On level (20 or 30 psi), the pump turns on
and runs until the pressure builds up to Off level (of 40 or 50 psi).
Jet pump is typically installed near the water source, elevated above the water level,
and must be protected from weather and accidental splashing. A foot valve (check valve)
is required for most installations to prevent backflow and to allow user to fully prime
the suction piping with water prior to operation.
Besides the suction/discharge outlets, a jet pump commonly has at least (3) additional
small outlets - one at the top for priming, one at the bottom for drainage and one at
the side for installation of a pressure gauge. These are factory-plugged by default and
can be utilized as needed.
Jet Pump Types
All jet well pumps can be divided into the following types
according to their internal construction and installation specifics:
Shallow Well Jet PumpsShallow well type jet
has a JE kit permanently built into the volute and has a single suction
inlet and a single discharge outlet. A shallow well jet pump has a suction lift of 25ft
and is intended for applications with relatively high water table and abundant water
(high well replenishment rate).
Deep Well Jet Pumps
“Convertible jet pump” and “deep well jet pump
” are interchangeable terms used
to describe a jet pump with an external, removable JE kit. When JE kit is attached to
the pump, it operates in a “shallow well” mode and has the same capabilities as the
shallow well jet pump. When JE kit is detached and installed submerged in a well, the
pump is converted to a “deep well” mode, capable of drawing water from down to 80ft
Jet Pump Sizing
There are several important factors to consider when selecting a
Water table is the most important factor when selecting a jet pump.
In areas with a constant, relatively high water table, a standard shallow well type pump
is generally adequate to provide constant water supply. In areas with a lower or varying
water table, a deep well or convertible pump is needed. Well capacity, standing water
level, drawdown water level and regeneration rates are all important specifics which
also must be accounted for.
As a rule of thumb, a 1/2 HP jet pump is sufficient to provide
water for a small home with a family of 2-3, provided that it is located close to the
3/4 HP pump is used in applications where two water fixtures may be used at the same
time, such as a shower and a kitchen sink or a laundry.
1 HP jet pump is used for permanent residence homes with several bathrooms and larger
Pumps over 1 HP are more typical for agricultural or commercial applications with high
Well TankWell tank
is a required
component for most water well systems, including jet well pump systems. Well tank
accumulates well water and holds it under pressure, creating a “pressure cushion” which
helps to maintain a steady water pressure at the plumbing fixture (faucet/shower, etc.)
and reduces frequent cycling of the jet pump, effectively extending its’ lifespan.