Pedrollo Pumps Cast Iron Shallow Well Jet Pumps 1/2 HP to 1-1/2 HP

Questions & Answers

What well conditions might possibly limit the capacity of the pump?

The Rate of flow from the source of supply; the diameter of a well; and the pumping level of the water in a well. These factors limit the size of the pumping equipment which can be used.

If there were no limiting factors, how is capacity determined?

The capacity is determined by the maximum number of outlets or faucets likely to be in used at the same time.

What is suction?

A partial vacuum created in the suction chamber of pump obtained by removing the atmospheric pressure, thereby allowing greater outside pressure to force the well water into the pump.

What is atmospheric pressure?

The atmosphere surrounding the earth presses against the earth and all objects on it, producing what we call atmospheric pressure. This pressure varies with elevation or altitude. It is greatest at sea level (14.7 lbs. Per sq. in.) and gradually decreases as elevation above sea level is increased at the rate of approximately 1 foot per 1000 feet of elevation.

What is maximum theoretical suction lift?

Since suction lift is the height to which atmospheric pressure will force water into a vacuum, theoretically we can use the maximum amount of this pressure 14.7 lbs. per square inch at sea level which will raise water 33.9 ft. From this, we obtain the conversion factor of 1 per square inch of pressure equals 2.31 feet head.

How does friction loss affect suction conditions?

The resistance of the suction pipe walls to the flow of water uses up part of the work which can be done by atmospheric pressure. Therefore, the amount of loss due to friction in the suction pipe must be added to the vertical elevation which must be overcome and the total of the two must not exceed 25 feet sea level. This figure must be reduced at the rate of approximately 1 foot per 1000 feet of elevation.

When and why do we use a deep well jet pump?

When the water level is more than 25 feet below the pump because this is the maximum practical suction lift that can be obtained with a shallow well pump at sea level.

What do we mean by “drive water”?

That water which is continuously recirculated under pressure by the pump to drive the jet.

Where the jet assembly is usually located in a shallow well jet pump?

In a shallow well jet pump it is inside the pump casing. In a convertible pump it is bolted to the suction side of the casing.

What is the principal factor which determines if a shallow well jet system can be used?

A maximum suction lift of 25' at sea level.

When is a deep well jet system used?

When the total suction lift exceeds 25 '.

What is the purpose of a foot valve?

It is used on the end of a suction pipe to prevent the water in the system from running back into the source of supply when the pump is not operating.

Can a foot valve be omitted from a Deep Well Jet System? Why?

No, because there are no valves in the Jet Assembly and the foot valve is necessary to hold water in the system when it is primed. Also, when the centrifugal pump isn’t running, the foot valve prevents the water from running back into the well.

Do I need to have a pressure gauge on my pump or system?

We suggest that you install pressure and vacuum gauges on all systems. The pressure gauge is like a speedometer on a car. The car will run fine without it but you won’t t know how fast you’re going. Likewise, the pump system will run fine without a gauge, but you have no way to know what pressure is in the system. In most cases, that is fine. But the gauge will be necessary if you ever have to diagnose a problem..

Do I need a pressure relief valve in my water system?

Most codes and ordinances require the installation of a pressure relief valve to protect operators and system components. The relief valve will open if the system pressure rises too high because of some kind of equipment failure. It will release the excess pressure in a controlled way instead of what could happen if something in your water system were to fail suddenly at high pressure.

What kind of pump do I need to pull water out of a reservoir tank?

If the tank is buried, treat it just like a well. If the pump is no higher than 25’ above the bottom of the tank, use a shallow well jet pump. If it’s further down, use a convertible deep well jet pump. If the tank is above ground and the pump next to it, use a shallow well jet pump. When pulling water from a tank we suggest adding a “low pressure cut-off” switch, to the system, to protect the pump in case the supply tank runs out of water.

Can I use a jet pump to boost the water pressure in my house or sprinkler system?

A jet pump can be used as a pressure booster, with some limitations. It is very important to consider that the resulting boosted pressure (incoming pressure plus the pressure the pump will add) does not exceed the maximum working pressure of the systems components. Thermoplastic jet pumps are not recommended for boost applications since most cannot exceed 70 PSI working pressure. For most cast iron pumps, the maximum total pressure cannot exceed about 100 psi. Most jet pump manufacturer’s manuals will have drawings for typical pressure booster pump applications.

What does “jet” mean in the term “jet pump”?

A narrow orifice mounted in the pump housing of a shallow well jet pump in front of the impeller is called a jet. The impeller moves water, called drive water, from the well through this jet. This constriction at the jet causes the speed of the moving water to increase, much like the nozzle on a garden hose. As the water leaves the jet, a partial vacuum is created that sucks additional water from the well. Behind the jet is a Venturi tube that increases in diameter. Its function is to slow down the water and increase the pressure. The additional water that is drawn from the well combines with the drive water to discharge into the plumbing system at high pressure.

What’s the difference between a “shallow” and a “deep” or “convertible” jet pump?

A shallow well jet pump can pull water from a maximum of 25’ depth-to-water at sea level ( less at higher altitudes) A deep well jet pump can pull water as deep as 80’ to 100’ depending upon model and horsepower. A shallow well jet pump have a built-in. nozzle & venturi.. In a deep well jet pump, the nozzle & venturi are in an ejector package that is mounted inside the well. In this type of setup there are two pipes connecting the pump to the ejector package. One pipe pulls the water up (suction) while the other pipe pushes some water down (drive) to circulate water through the nozzle and venturi. Water moving through that nozzle & venturi makes a pressure differential that brings the water up to the pump.

What’s the difference between “deep well” jet pumps and “convertible” jet pumps?

Convertible jet pumps can be converted as either a shallow or deep well pumps. In a shallow well installation an shallow well ejector kit is bolted to the nose of the pump. In deep well installations the ejector kit is mounted down the well

Q. How can I figure out my water level in the well?

Open the top of the well it up and drop down a fishing line with a cork and weight attached to the bottom. When the bobber is floating on the water, you will no longer feel the weight on the line, Measure how much line you have dropped down the well to know the water level. Is it possible for my water level in the well to change? Yes. The normal water level can change during periods of drought or excessive rains. Some wells are also low-producing, and the ground water comes in and fills the well slowly, In slow producing wells, the water level could drop while the water is being pumped out. If the water level drops to more than 25 feet, a shallow well pump will not pull the water up. When the level drops, it could drop below the pump’s suction pipe inlet. If this happens the pump would lose its prime.

Can I reuse my old jet package to work with a new pump from a different brand?

No…….. Each manufacturer matches the flow rate of the nozzle and venturi to their specific pumps.

Can I use a jet pump to pull water out of a well, lake, or river for my sprinkler system?

Yes. Jet pumps make excellent pumps for small sprinkler systems. You will need to choose a pump that will deliver about the same amount of water as your sprinkler system requirements. If your sprinkler system requires more than the jet pump can, you can split the system into fairly closely-matched zones. Then choose a jet pump that matches the requirements of one zone. You should provide some sort of suction strainer to prevent debris from entering clogging the pump

What size or horsepower of pump do I need?

The peak time for household water use is normally in the morning, when the family rises, or in the evening, when all are home. Seven minutes is the average high water use timeframe for a shower or automatic washer. For a 1 bathroom home figure 7 GPM; for a 1-1/2 bathroom home figure 10 GPM; for a 2 to 2-1/2 bathroom home figure 14 GPM and for a 3 to 4 bathroom home figure 17 gallons per minute Values given are average and do not include higher or lower extremes. Peak demand can occur several times during morning and evening hours. Additional Requirements: Farm, irrigation and sprinkling requirements are not shown. These values must be added to the peak demand figures if usage will occur during normal demand periods.

Do I need to use a check valve or foot valve with this pump?

Some jet pumps have a built-in check valve and do not require a second one. For the rest, it is recommended that you do use a check valve or foot valve in order to maintain the prime in the pump between uses. If none is present you would need to prime the pump every time you use it. The check valve should be installed in the suction side piping as close to the source of water as possible. It should not be installed within 2’ of the pump’s inlet, or anywhere on the discharge side of the pump. A foot valve functions just like a check valve plus has a strainer on it. It goes on the end of the suction line in the water.

What voltage do these pumps need?

Most of the ½ HP jet pumps are shipped from the factory connected to run on 115 volts but most can be reconnected, in the field, to run on 230 volts. . Most of the ¾ HP to 2 HP jet pumps are shipped connected for 230 volt operation but are switchable, in the field, to 115 volt operation.. We suggest the services of a qualified and competent contractor to do all the electrical work as per all applicable codes.

Can I run the pump at a higher pressure than what they are set up for from the factory?

Yes…The pressure switch attached to the pump can be adjusted for different pressures. It is very important that you do not adjust the pressure switch to a pressure that is higher than the pressure the pump is capable of reaching.

Which is better, a cast iron or a plastic pump?

We sell both kinds because there is a demand for both kinds. The internals of most of both types of pumps are made of thermoplastic parts. The casing and bracket are there only to hold the pump together and protect it. Cast iron components are stronger in case the pump is in an area where it might be hit by something. Thermoplastic jet pumps are not recommended for boost applications since most cannot exceed 70 PSI working pressure, More important than the type of material the body is made of, is to choose the pump that will perform best in your particular application. Most professional contractors will purchase cast iron pumps.

Is there a problem with choosing a pump that is too high in horsepower?

The biggest considerations here are that your electric bill will be higher; and your pressure tank will need to be large enough to avoid of rapid cycling. We suggest that you use a pressure tank that is large enough so that every time the pump runs, it can run for a minimum of 1 minute, preferably 2 minutes

Why does rapid-cycling hurt the pump?

When an AC motor starts, it draws higher current than when it’s just running. That high surge also builds a lot of heat inside the motor. The pump should be able to do the work it needs to and then shut off. It should be off long enough so that it can completely cool off. If it has to start again before it’s completely cooled off, the motor is going to get hotter. Heat shortens the life of electric motors.

What size generator do I need to run this pump?

You need to know the amp draw of the pump and multiply that by the voltage to get the watt usage of the pump. Example: Pump draws 5 amps on 115 volts. 5amps x 115volts = 575 watts. AC motor can draw three to five times its regular amp draw for about ½ second when it starts up. So to run our example pump, we need a generator that can supply a startup surge of at least 2875 watts (575 x 5) and can continue to supply the 575 watts as the pump runs. Keep in mind this is accurate if the pump is the ONLY thing the generator is going to supply power for. If you also want to run lights, etc. then that needs to be added to the generator size. We suggest that you contact a Generator supplier to determine the proper sizing.

Where do I find the model number and date of manufacture on my pump?

The pump’s nameplate on the pump will have the model number and date code on it. The date code is usually a combination of letters and numbers.

Q. Where can I get repair parts for my pump?

We do not sell parts….Installation and parts manuals are provided only as reference tools. Neither the manufacturer nor King Pumps makes any representation or warranty of any kind to the Buyer that he or she is qualified to neither install nor make any repairs to the product. In fact, the manufacturer and King Pumps expressly state that installation, repairs and parts replacements should be undertaken by qualified and competent technicians or contractors and not by the Buyer. The Buyer assumes all risk and liability arising out of his or her installation or repair to the original product.

Can I leave the pump right out in the rain and sun?

The pump motor is considered to be “drip-proof” but not weather-proof. You need to protect the pump from rain and other water, but still need to allow for air to circulate around the motor. You cannot just put the pump in a big box unless there is a lot of ventilation.

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