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MAJOR
COMPONENTS
AND
WHAT
THEY
DO
Tank and Air Volume
Control
The tank serves two tractions:
1.
It provides
a reservoir
of water. Some of this water
is drawn offwhenever
a house fixture is opened
(so
that the pump
doesn't
need to start every time you
open a tap).
2.
It maintains
a cushion
of air under
pressure.
A standard
tank
requires
an Air Volume
Control
(AVC) to add air to the tank when
needed.
See the
instructions
included
with the AVC for details of in-
stallation
and operation.
A SEARS Captive
Air * tank
maintains
a constant
precharge
of air in the tank
and does
not require
an
AVC. An annual check on the tank pre-charge
pressure
is recommended.
Impeller
The pump's
impeller
rotates
with
the motor
shaft,
causing
the water
to fly out from its rim by centrifugal
force. The rotation
of the impeller,
along with the mo-
tion of the water, creates
a vacuum
at the center
of the
impeller
(the
"eye" of the impeller)
which
pulls
in
more water.
The Vertical Multi-Stage (VMS) pump
has two or three
("multiple")
impellers;
the water
feeds through
them
one after the other, with each impeller
adding
to the
pressure.
This allows the VMS jet pump
to pull water
from
greater
depths
and at a higher
pressure
than
a
conventional
single stage jet pumps.
Jet
The jet is a nozzle/venturi
arrangement
installed
in the
well which drives water up to the pump
from the well,
boosting
the water
pressure
going into the impellers.
The jet allows water
to be lifted from a greater
depth
than would
be possible
with
only the impeller
eye's
vacuum.
In order to drive the jet, part of the discharge
stream
from
the pump
is diverted
back
"down
the
hole" to the jet to help lift water from the well into the
pump
suction.
Pressure Regulator
The pressure
regulator
is adjusted
at installation
to di-
vert the correct
amount
of water back to the jet for the
most efficient
operation.
Under certain
conditions,
the
pressure
regulator
may require
adjustment
during
the
pump's
life (see Page 10) to restore
or maintain
the
pump's
efficiency.
Pressure
Switch
The pressure
switch
automatically
starts
the pump
when
the pressure
in the tank drops to 40 pounds
per
square
inch (PSI) and stops the pump
when
the tank
pressure
reaches
60 PSI.
Adapter
Flange
The VMS pump
is equipped
with
an adapter
flange.
This adapter
facilitates
installation
and removal
of the
pump without
disturbing
piping.
See Pages 6 and 7 for
more information.
Pressure ReliefValve
Under
certain
conditions,
VMS pumps
can generate
very high pressure.
The pressure
relief valve is installed
to make sure that the pressure
in the system does not
exceed
the pressure
which
the system can carry safely.
The pressure
relief valve must be able to pass all the
water the pump
can produce
at the system's
rated pres-
sure. Install
a relief valve (Sears Stock No. 27229)
set
to open
at 75 PSI. between
the pump
and the tank.
There should
be no shutoff
valves between
the pump
and the relief valve. See Figures
11 and 12, Page 8, for
more information.
Pump
Mounting
The pump
base
has four
equally
spaced
3/4" NPT
threaded
sockets.
These
will take threaded
pipe
for
legs, to allow enough
room
to make piping
connec-
tions under
the pump.
In the case of a single pipe installation
(see below),
the
pump
can be placed
directly
over the well, using the
offset nipple
furnished
with the casing adapter
to con-
nect the pump
to the well head.
Piping
When
installed
on a 'double
pipe' jet, one pipe is the
pressure
or drive pipe; this pipe sends water down into
the well to the jet. The other pipe is the suction
pipe;
this pipe carries
water
up to the pump
suction
from
the jet. Because
of the pressure
requirements
and
depth
of multi-stage
jet pump
installations,
use the
chart below
for pipe selection.
When
installed
on a singe pipe
jet, the well
casing
serves as the drive pipe, carrying
water to the jet. The
drop pipe inside the well is the suction pipe, carrying
water up to the pump
from the jet.
Use a 'single pipe' system for a 2" or 3" well; use a 'dou-
ble pipe'
system for a 4" or larger well. See Pages 6 and
7 for details. Follow
instructions
packed
with jet pack-
age to get proper
nozzle
and venturi
combination
for
your pumping
depth.
Use 1-1/4" pipe for both suction
and drive pipes.
A 1"
nipple,
a 1-1/4"xl"
facing
bushing,
and a 1-1/4" cou-
pling are included
in the jet package.
These
must be
used with the jet. (See Figure 8, Page 6, for installation
details.)
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