Well pump / water pump protection devices & switches
Manual & automatic switches shut off the well pump in low-water conditions
WATER PUMP PROTECTION SWITCH - CONTENTS: how to choose & install a switch to protect water pumps or well pumps against damage if the water supply or well water fails or if there is no water pressure in the system. How to use manual-reset pump pressure control switches that shut down the well pump.
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Well pump or water pump protection switches & controls:
What can we install to protect a water pump from damage if the well runs out of water? How do we protect the well pump from damage due to pump short on-off cycling? How can we protect the well pump and its circuit from electrical overloads or lightning damage?
This article describes all of the devices to protect water pumps from damage from continuous running, short cycling, overloading, no well water, low yield wells, power surges, or lightning strikes.
Water Pump Protection Switches Guard Against Pump Damage & Overheating
Watch out: A water pump or "well pump" can be damaged by conditions that cause the pump to run continuously, particularly if the pump is running "dry" - without water passing through its mechanical parts. The result can be the need for a costly repair or for pump and control replacements.
[Click to enlarge any image]
Worse, a more powerful pump, especially a submersible pump that fails to turn off when it should may also pump water at high enough pressure to burst pipes, flood a building, or injure a bystander - dangers we discuss separately
at WATER PRESSURE TOO HIGH: DANGERS
Well pumps can also be damaged by other conditions such as low voltage, lightning strikes, entry of debris in the well water, or corrosive water.
Generally when readers ask what to do about a pump that won't shut off we suggest that they take the following steps
Turn off the pump right away - if you let the pump run dry for too long it's likely to be damaged.
Diagnose the trouble and repair it -
see WATER PUMP WONT STOP RUNNING. The problem may be something easy such as a cut-out pressure set too high, or it may be more trouble, such as a well that has a very poor flow rate. In between are problems such as debris-clogging that prevents a pressure switch from properly sensing water pressure or leaks in well piping.
Install an appropriate device to protect the pump from damage due to chronic conditions such as a well that frequently runs low on water . Here
at WATER PUMP PROTECTION SWITCH we describe all of the various devices installed to protect a well pump and its wiring and controls.
Reader Questions: Water Pump Won't Stop Running - can I install an automatic shut-off
(May 31, 2011) Rico Zambrano said:
My pump keeps running and wont shot off, I have good water pressure.
(Apr 25, 2012) Ernie Parsons said:
I live in the North (Nunavut) and our water is supplied by truck and held in a 700 gal. tank. Sometimes when it storms and the trucks fall behind schedule and we run out of water. The problem is when this happens the pump continues to run and if we don't catch it quickly it heats up and ruins the impeller centre or the bearing. My question: is there a shut off I can install on the pump or water line that will shut the pump off when the tank is empty.
Reply: yes. here is a list of the types of well protection devices available along with where-to-buy information
If your water pump keeps on running and won't shut off,
1. TURN IT OFF manually so you don't burn up the pump motor.
Yes there are more sophisticated water pump controls with sensors that can shut off the pump it it's pumping air. Typically these work by monitoring the current draw of the pump, the pump motor temperature, or actual water flow.
There are also water pick-up "tailpiece" fittings intended for use in a well that might work in your tank that will recycle water through a pump to prevent its burn-up when water runs too low at the source.
Water Pump / Well Pump Protection & Switches & Devices
Built-in Electric Motor Overheating Protection: some electric motors including some submersible well pumps include a built-in electrical overload or temperature overheat control switch that will turn off the electric motor if it's too hot. On inaccessible motors such as a submersible well pump the overload or overheat switch includes a thermal sensor that will automatically re-set the switch when the motor cools down. Other electric motors may include a pop-up switch that must be manually re-set.
Electrical circuit breakers or fuses found in the electrical panel feeding the electrical circuit for the pump motor and its controls are designed to turn off electrical power to a water pump or well pump circuit if the circuit is drawing excessive current at an unsafe level.
Watch out: if you find that a well pump is continually tripping a circuit breaker or blowing a fuse you should leave the circuit OFF as it has become unsafe.
Flow Sensor Switch: flow sensors are controls mounted in line in water supply piping that sense water flow or movement in the pipe. Used typically on irrigation systems, these water flow rate sensor switches can be used to measure actual water flow rate, compare that to a set standard, and shut off the pump if the flow rate is too low (running out of water) or too high (a burst pipe).
Recommended: Flow Valve to protect pumps on low-flow-rate wells: a flow valve such as the Dole® Valve flow restrictor (for example a GB-3.0 or other suitable model) can limit flow rate in a well pumping system to a flow rate that is less than the in-flow rate of water into the well bore. The flow restrictor valve is placed in the piping line between the water pump discharge port and the water pressure tank. In this position the water flow rate can be restricted to protect the pump from damage from running dry - as will happen if the pump draws the well water level down to below the pump inlet.
The installer will determine the proper flow restrictor size (in gallons or litres per minute) by using an adjustable gate valve placed between the pump outlet and the water tank. The gate valve is partially closed with the pump running, thus restricting the outflow from the pump's dischage port.
The level of water in the well is monitored. When the pump has run at this reduced output long enough to be confident that it is not pumping faster than the well's recovery rate the output flow is measured (in gallons per minute for example) and an appropriate flow control valve is selected and permanently installed where the gate valve was located.
Excerpt from the producer's product description: The Dole® Flow Regulator is self-cleaning and
designed to deliver a constant volume of water flow
over a wide pressure drop range. The controlling
mechanism is a flexible orifice that varies its effective
area inversely with applied pressure so that a constant
flow rate is maintained. - retrieved 25 Feb 2015, original source: GE Infrastructure Water & Process Technologies, "Dole Flow Control Valve", GE Corporation (2004).
Dole valves are presently produced by Water & Process Technologies, a General Electric Company located in Trevose, PA, TRel: 215-355-3300. The company has offices world wide and its products are distributed to end consumers through plumbing suppliers. Dole valves and similar devices are sold in flow rates ranging from 1/2 GPM (1.9 LPM) to 12 GPM (45.4 LPM) with inlet pipe diameter connections varying accordingly from 3/8 FNPT to 1 FNPT.
Watch out: be sure to install the flow restricting valve in the proper position, with its arrow correctly matched to the direction of water flow.
Low Pressure Protection Switch: Aquatec (LPS340-G) Low Pressure Protection Switch (intended for booster pumps), described as follows:
The LPS Low Pressure Switch electrically shuts off the booster pump if the feed water is interrupted. The LPS is designed to be mounted on the inlet side of the pump.
Although the pump will not be damaged if operated without feed-water, pumping air into the membrane for extended periods can damage the module. We strongly recommend this device for applications where feed-water shut-off or interruption can occur. The LPS includes a wiring harness (not shown) that interconnects a pump and transformer.
Recommended: Water pump pressure control switch with low-pressure cut-off feature: such as the Square D FSG2J24M4CP Water Pump Pressure Switch with Low-Pressure Cutoff, sold under the PumpTrol or SquareD brand produced by Schneider Electric, this series of water pump pressure control switches include a low water pressure cutoff feature.
At low water pressure this switch will shut off the water pump system until it is manually re-set. Depending on the operating pressure range for normal cut-in and cut-out water pressure factory pre-sets in this switch, Square D offers 21 different Pumptrol water pressure control switches, of which six have a built-in low-water-pressure cut-off feature, four have a manual cut-out lever, and two include a pulsation plug.
Recommended: Water pump relay switch with built-in low pressure or overload cut-off features. Larger horsepower well pumps, usually submersible models, are switched on and off by a heavy-duty pump relay switch that is itself operated by the water pump pressure control switch described above.
Among water pump relays are more sophisticated models that include sensors that can shut off the pump it it's pumping air. These pump relay controls usually work by monitoring the current draw of the pump, or in some cases the pump motor temperature, or actual water flow. For example
Pumptec pump protection device, Franklin Electric,
400 E. Spring St.
Bluffton, IN 46714
Tel: 260-824-2900 Fax: 260-824-2909
www.franklin-electric.com. The company offers a submersible pump service hotline for their products: 800-348-2420. [Please don't embarrass us and yourself by calling Franklin to ask about other pump brands.]
The company's description of their PumpTec controller includes:
Pumptec is a microcomputer based pump
protection device that continuously
monitors motor load and power line
conditions to provide protection against
dry well conditions, waterlogged tanks,
and abnormal line voltage conditions.
Indicator lights provide complete system
status, which can be easily viewed
without removing the cover.
interrupts power to the motor whenever
the motor load drops below a preset
level or the load drops quickly.
Pumptec is optimized to work with
Franklin 2- & 3-wire single phase motors
from 1/3 to 1.5 HP. An underload (dry
well) adjustment is provided to address
The PumpTec controller uses three indicator lights to indicate power, electrical load, and voltage levels. An "underload" indication can indicate that the well is dry while an "overload" indication typically means that there is a problem with the pump motor, causing it to draw excessive current.
PumpStop universal pump protection switch [shown above in a photo & wiring sketch from the company's website] for jet pumps & centrifugal pumps, protects against loss of pump prime, stuck or failed pressure control switch, broken valves, stuck relays, loss of water in the well itself, user error, check valve failure. The switch is simply wired into the pump power line input tothe pressure control switch, in series.
Description [quoting the company's technical data sheet]: Pump overheat damage is caused when water stops flowing and the pump continues to run. This causes the water in the pump to get very hot resulting in total system failure. The POP 120 shuts off the pump before overheat damage occurs, keeping the pump system safe until repairs can be made.
Contact: PumpStop, General Contracting Services
P.O. Box 631
Cocoa Beach, Fl. 32932
321-333-9887 Tel: 321-333-9887, Website: www.overheatprotection.com
The instructions for installing this device call for interrupting either of the two 120V input or "hot" wires to a 240V pump pressure control switch to wire the PumpStop in series. Indeed switcing one-leg of a 240V circuit should turn off the pump.
Watch out: safety hazards remain when you power off only one leg of a 240V circuit if someone working on the circuit thinks that all power is off when in fact one leg remains live or "hot".
You might check with your pump manufacturer and with the manufacturer of any other controls that may be wired in the circuit, asking about the effects of interrupting only one of the power wires to the pump. We have on occasion heard from readers who got into trouble interrupting one leg of the two 120V legs that typically power a 120V motor or circuit, depending on how those two legs were used. A reader asserted that on loss of one leg of the 240V pump circuit, their particular pump continued to run but at a slow speed. For example when a remaining 120V leg of a circuit is left "hot" there may be current leak or safety risks remaining at the wired device.
Generally a pump or other electric motor won't be damaged if there is full voltage or no voltage provided to the device. Reduced voltage can cause damage.
We requested clarification from the manufacturer via their website contact form on 7 Oct 2015 - follow-up will be posted here.
Watch out: 240V circuits are not wired identically world-wide. The pump protection switch and simple wiring diagram shown above are for a North American installation. In the U.S. and Canada a 240V60 Hz circuit is "single phase" and does not make use of a neutral wire and the two legs complete a 240V circuit. But in the U.K. 240V 50Hz is provided on a single phase circuit by one single wire, always requiring in addition a neutral wire to complete the circuit and a ground or "earth" wire for safety.
Water pump short cycle stop valves are devices intended to detect short on-off cycling of the well pump and to shut down the pump.
See WATER PUMP SHORT CYCLE STOP VALVE and
for an explanation of what causes a water pump to turn on and off too often or too rapidly,
see WATER PUMP SHORT CYCLING
Water tank explosion protection: a pressure relief should be installed on any pressurized water tank or on the tank-tee that connects plumbing to the water tank. Details are
at WATER TANK PRESSURE RELIEF VALVE
Well Pump Overheat Protection Switch, Model POP 120 sold by Discount Sprinkler, 6831 Tierra Verde St., Pt. Richie FL 34668, Tel: 727-841-7000, Website: overheatprotection.com, Email: email@example.com. If the pump gets "hot" this thermal sensor will shut down the motor to allow the pump to cool down.
Watch out: This switch will shut down the pump after 10-15 minutes of dry & "hot" running, give a 30-50 minute cool-down time, then will allow the pump to re-start. The manufacturer opines that this cycling will not damage the pump.
But I'm not sure this is exactly suitable for your situation as the switch, like a thermal overload switch used on some electric motors, can reset and allow the pump to start again when cool. Repeated cycling of a water pump running dry, even with a cool-down period, may still damage the pump impeller or bearings.
Well piping tailpiece: a WELL PIPING TAIL PIECE is a device installed in the well at the foot valve or at the submersible well pump to detect that water level in the well has fallen to a too-low level for safe pumping.
When water falls to this low point and the pump runs water circulates in the tailpiece (or inside the submersible pump) to prevent pump overheating, but actual withdrawal of water from the well is slowed or stopped entirely to protect the pump.
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Square D 9013 series pressure control switches provide these special water pressure control switch features: narrow pressure differential controls, higher horsepower pump control switches, manual on/off switches, automatic low water pressure cut-off, pulsation plugs, and other features.
Narrow Differential Pressure Switches
Schneider Electric provides narrow differential switches including 6-20
PSIG differential switches. Choose from the 9013FSG42/49 or higher
HP 9013FYG42/49. Also available is the 9013FRG with reverse action.
The 9013FRG pressure switch is non-adjustable differential with 6-14
PSIG cut-in and 1-11 PSIG cut-out ranges.
Higher HP Pressure Switches
Need a larger HP motor for longer runs in deep wells? Then look to
the 9013FYG or 9013GHG pressure switches. These switches directly
control all types of pumps up to 5 HP and can be used in the control
circuit of a magnetic starter for even larger pumps.
Manual On/Off Switch
The 9013 series of pressure switches offer an optional on/off switch.
This allows you to manually turn on and off your pump system for
extended periods of time.
Automatic Low Pressure/Water Cut-off
If system pressure is lost for any reason, a low water condition for
example, the automatic lower pressure/water cutoff feature will open
the contacts, turning off the pump.
Pulsation plugs are available to control pressure due to increased start
up pressure generated by high speed jet pump motors or by valves
prone to a surge in pressure.
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