Water Pump Types Defined
Life Expectancy of Well Pumps InspectAPedia® -
Definitions of types of well water pumps: one line jet pump, two line jet pump, submersible pump, hand pumps, kinetic water ram water pumps
What is the expected life of a well water pump? How long should a well pump last?
What factors affect the life expectancy and pressure ability of water pumps?
How can we extend the life of a water pump, and how do we know when to replace the pump or pump controls?
If we wire a well pump or other electric motor at 240V will it reduce the electric bill?
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This article describes factors affecting the Life Expectancy of Water Pumps and pump controls.
Readers of this document should also See WATER TANK LIFE EXPECTANCY andWELL LIFE EXPECTANCY, but before assuming that a water problem is due to the
pump or well itself, see
Water pump and pressure tank repair diagnosis & cost a specific case which offers an example of diagnosis of loss of water pressure, loss of water, and analyzes the actual repair cost.
Life Expectancy of Water Pumps - varies by pump type, usage, and other factors
In this article we discuss how long you can expect a water pump to last and what factors affect its life. Specifics of different types of water pumps can be read in detail at these articles:
WATER PUMP, ONE LINE JET - what is a one line jet pump, how do they work, what goes wrong PUMP, TWO LINE JET - what is a two-line jet pump, how do they work, what goes wrong PUMP, SUBMERSIBLE - what is a submersible pump, how do they work, safety warnings PUMP, WATER PRESSURE BOOSTER - how to get more water pressure even on municipal water supply systems
How Long Does a Water Pump Last?
Jet Pump Life Expectancy:
An above-ground one line (shallow well) or two line (deep well) jet pump often operates for a considerable range of
years, as few as 4 years or as many as 15 or 20 years before needing replacement.
A typical well pump life expectancy (lumping both the electric
pump motor and the pump assembly together) is about 10 years in the U.S. and Canada, and about 5 years in Mexico and Central America.
A submersible well pump, perhaps because the motor is kept cool by being immersed in well water,
can also have a considerable range of life expectancies depending on the variables which we list below.
A submersible pump operating in low-sediment
water may have a 15 year life while the same pump in high sedimented water and without adequate sediment and check valve protection may fail in
5 or 6 years.
At left our sketch of a types of well water pumps is courtesy of Carson Dunlop. The drawing shows the key differences between a one line jet pump, two line jet pump, and a submersible water pump.
Factors Affecting the Expected Life of a Well Water Pump
Water Pump duty cycle: a water pump which is called-on to run just a few times a day will have a considerably longer life than the same pump under heavy or continuous use. One of the reasons that owners install
a larger or captive-air bladder-type water pressure tank is to extend the water draw-down cycle and thus reduce the frequency of turning the water pump on and off.
Water Pump electric motor horsepower or motor size: for the same application and workload, a larger electrical motor, for example a 3/4 or 1 HP (horsepower, or CP, caballo podre in Latin America) motor
will usually outlast a small fractional 1/8 or 1/4 hp electrical motor.
Water pump motor quality will affect how long the pump's electric motor (or any electric motor) will last. Variables include the type and quality of electric motor bearings and its lubrication requirements.
Where an electric motor is manufactured, even when it claims to be the same brand, can make a significant difference. For example according to our Mexican consultants, electric pump motors made in Mexico sometimes
perform less durably than a similar motor manufactured to U.S. standards.
Water sediment is a major wear factor on the pump assembly itself (as opposed to the electric motor that drives the pump). Sediment in water acts as an abrasive that wears pump bearings and other
moving parts.
Quality of Water Equipment Installation: can make a big difference in the life of the water supply equipment. Installers who simply hook up a pump and wiring, with no understanding of the importance
of proper location of check valves, filters, proper electrical wiring, etc. are likely to be providing a shorter-lived water supply system.
Which Parts Wear Out on Water Pumps?
What looks like "a well pump or water pump" actually is a collection of major assemblies and more numerous minor parts.
The major assemblies on
an above ground water pump (such as a one line or two line jet pump) include the electric motor that drives the pump and the actual pumping assembly
that moves water from the well to the water pressure tank and on into the building.
You an see the pump impeller in the sketch at left. Hard water, dirt and sediment, little stones, or other debris can damage this component: the pump motor may run just fine but less water pressure or flow may be delivered by the pump.
A submersible pump includes these two major assemblies (electric pump motor
and water pump assembly) and adds an internal check valve.
Pump impeller or rotary vanes that move water - see sketch above
Pump motor bearings inside the electric motor that drives the water pump
Internal pump check valves
Pump control switches which are normally physically separate devices, also wear or fail, becoming clogged with sediment or suffering burned electrical contacts. See WELL PUMP PRESSURE CONTROL ADJUSTMENT for details.
How Can We Maximize the Life Expectancy of a Well Water Pump?
Install a sediment filter ahead of the water pump in above ground water pump installations. Most well equipment installers place a filter after
the water pump, or even after the water pressure tank rather than ahead of these components. If the well water has a high sediment level placing a sediment
filter upstream or before the water passes through the water pump will extend the pump life significantly.
Install check valves where they will protect the water pump from loss of prime and having to work as hard to restore prime. For example, while
most submersible pumps contain their own integrated check valve, installing a second check valve at the top of the well or further in the well piping
reduces the load on the water pump's internal valve, protects against loss of prime in the well piping, and extends the life of the water pump itself.
Select a pump motor horsepower or size which is appropriate for the anticipated usage or duty cycle for the well and pump installation. In general
a larger motor will outlast a smaller pump motor. If your pump motor and control are labeled indicating that it is permitted to run the pump at either 120V or 240V, and if you are installing the pump new, there are some advantages to wiring the pump to operate
on 240V rather than 120V. The motor will start more easily and you might improve the pump motor life.
Most well pumps, except the very smallest models, can be wired to run at either voltage level. The higher voltage will make it easier for the pump to start. The efficiency of the water pump and its operating cost will be about the same regardless of the voltage used. See Efficiency of 120V vs 240V Equipment for an answer to the question of whether or not changing a well pump from 120V to 240V will save in operating cost. (Basically, no.) Also See DEFINITIONS of ELECTRICAL TERMS for definitions of Amps, Volts, Watts, Ohms, etc.
Perform necessary pump maintenance: some water pumps require inspection and replacement of internal parts such as bearings or impellers
as often as after just four or five years of use. While it may be possible to ignore this maintenance for a while, the effect may be to so wear
the pump or pump motor parts that complete pump or pump motor replacement are necessary.
Check available voltages on the pump motor circuit. We speculate that some electric motors will fail sooner if they are required to
frequently operate at voltages lower than their design voltage range.
Maintain the water pressure tank: a water pressure tank which has lost its air charge and is short cycling is very hard on and
shortens the life of a water pump. See SHORT CYCLING WATER PUMPS
See WATER PUMPS & TANKS for a discussion of common failures and
repairs on water pumps and water tanks.
Life expectancy of water pump controls and switches
See WELL PUMP PRESSURE CONTROL ADJUSTMENT and its companion
articles which include
a discussion of the life expectancy and common modes of failure of water pump and tank pressure controls.
Other Types of Water Well Pumps
Kinetic water ram water pumps
A kinetic water ram pump uses the force of running water in a stream combined with the principles of hydraulics to lift water as much as 50 meters from the pump location. The water ram was invented in 1780 by Frenchman Joseph Michael Montgolfier.
Since surface or stream water is unlikely to be sanitary in most locations, water ram pumps are used mostly in agriculture to move stream water to fields for irrigation.
A very different water ram, a "kinetic water ram" pump using compressed air to clear clogged building drains is available and is discussed at CLOGGED DRAIN DIAGNOSIS. That kinetic water ram is a drain clearing tool not a water pump.
Photo & Description of Hand Pumps and Windmills or Mechanical Pumps for Pumping Water
A variety of mechanical pumps has been in use for thousands of years, including human or animal-rotated water wheels to lift water from a river or stream and more recently piston-type pumps that combine a vertical rod and handle to lower and then lift a piston in a pipe or tube, "sucking" water from as deep as 20 feet to the surface.
A hand pump on a well will have trouble lifting from much depth. Still deeper wells were traditionally accessed by the simple bucket and rope method.
Photo & Description of Piston Type Well Pumps
A mechanical version of the hand pump on wells (shown just above) was able to lift from somewhat greater depth, perhaps as much as 20 feet.
The well pump motor and its vertically-operated piston was set directly over the well casing as we show in the photo of an old, discontinued piston well pump.
In our photo you can see the large pulley wheel on the right side of the vertical piston pump, but the drive belt and motor that drove the pump have been removed.
What are Artesian Wells & How do They Work?
Water flows naturally to the ground surface of an artesian well, pushed there by higher pressure groundwater deeper in the earth. "Artesian" refers to Artois, the region in France that gave this type of water source its name. The Latin form of Artois is Artesia.
The level of groundwater is not "flat" under the surface of the earth. Rather underground water tends to follow the countours of the ground surface.
When the underground water reservoir is actually higher than the well that taps into it, water is forced from the higher level to the surface of the artesian well.
At Sinkholes in Estonia-The Witches' Well we describe a non-artesian well that also pushes groundwater to the surface when a nearby underground river floods.
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Thanks to Alan Carson and Bob Dunlop, Carson Dunlop, Associates, Toronto, for permission to use illustrations from their publication, The Illustrated Home which illustrates construction details and building components. Carson Dunlop provides home inspection education, publications, report writing materials, and home inspection services. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
Kinetic water rams are described and demonstrated at waterram.com/faq.php
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