GENERAL

INFORMATION

 

 

 

 

 

Table h Pump Performance Chart (In Gallons Per Minute)

 

 

 

 

 

 

 

Discharge

 

 

 

 

Pump

 

Suction

Discharge

Pressure

Pumping Depth in Feet

 

Model

Description

Size

Size

P.S.I.

5'

10'

15'

20'

390.2508

1/2 HP Standard S.W. Jet

1-1/4"

3/4"

40

7.3

6.2

5.2

4.2

MAJOR COMPONENTS AND

WHAT THEY DO

 

Relief

 

Valve

 

ie Tee

Water System

and Priming Plug

 

Built-in

 

Check

 

Valve

23140E96

Figure I

Impeller and Jet

Impeller turns with motor shaft, causing the water to fly out from its rim by centrifugal force. Impeller rotation creates a vacuum which puUs in more water. Part of the water is di- verted back to the jet where it passes through the nozzle and venturi. This creates more vacuum to draw in more water.

In shallow wells (less than 20 feet deep), the vacuum cre-

ated at the pump is enough to pull water to the pump.

Therefore, for shallow well use the jet is built into the pump.

PIPING

Piping in the Well

A Shallow well jet pump can be installed on a dug well, drilled well or with a driven point. In a dug or ased well, a foot valve and strainer should be installed for easy priming. It should be five to ten feet below the lowest level to which

the water will drop while pump is operating (pumping water level).

The strainer should not be too close to the bottom or sedi- ment may clog it. Before installing the foot valve, check to see that it works freely.

When installed on a driven pont well, your Shallow Well Jet Pump should have a check valve installed as shown in

Figure 2.

To Household

Discharge Tee

Water System

f- and Priming Plug

II _--Relief Valve

Drive

Point

Air Volume Control

The air volume control (AVC) maintains the cushion of air in Standard tanks.

Pressure Switch

The pressure switch provides automatic control.

MODEL NO. PUMP STARTS AT [PUMP STOPS AT

390.2508

_

/ _

Check Valve or Foot Valve

This pump is equipped with a built-in check valve. Install a

foot valve in the well on dug or cased wells. See Figure 3, Page 4.

Tank

The tank serves two functions. It provides a reservoir of water, some of which can be drawn through the house fix-

ture before the pump must start. It maintains a cushion of air under pressure.

Two types of tanks are available: Captive Air® and Standard.

No air vohtme control is needed with Captive® Air Tanks.

Couplin9

NotOrive

toPoint

Scale

Figure 2

For a pump at sea level, be sure the vertical distance (lift) from the pumping water level to the pump is not over 20

feet if the pump is over the well. This wll be less if the pump is offset from the well.

The maximum lift of any pump decreases at the rate of about 1' less lifx for every 1,000 feet elevation above sea level. For

example, if your are at 5,000 feet elevation such as in Denver, Colorado, you would loose five feet of llfx. The max- imum depth from which oyou could pump water would

therefore be 15 feet.

Page 3
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Sears 390.2508 owner manual General Information, Major Components What They do, Piping