The Driller
  • Sign In
  • Create Account
  • Sign Out
  • My Account
  • NEWS
  • CLASSIFIEDS
  • EQUIPMENT
  • SAFETY
  • VIDEOS
  • EDUCATION
  • SOURCEBOOK
  • EVENTS
  • SUBMIT
  • ABOUT
  • SIGN UP
cart
facebook twitter linkedin youtube
  • NEWS
  • Water
  • Geothermal
  • Construction
  • Environmental
  • Mining
  • All Industry News
  • EQUIPMENT
  • Rigs & Heavy Equipment
  • Consumables
  • Pumps
  • Featured Products
  • VIDEOS
  • Newscast
  • Drill Talks
  • Ask Brock
  • Emerging Drillers
  • EDUCATION
  • Drilling Business Insights
  • Reference Desk
  • Sponsored Insights
  • EVENTS
  • Conferences & Demo Days
  • Newscast LIVE
  • SUBMIT
  • Drillers @Work
  • ABOUT
  • Contact
  • Advertise
The Driller
search
cart
facebook twitter linkedin youtube
  • Sign In
  • Create Account
  • Sign Out
  • My Account
The Driller
  • NEWS
    • Water
    • Geothermal
    • Construction
    • Environmental
    • Mining
    • All Industry News
  • CLASSIFIEDS
  • EQUIPMENT
    • Rigs & Heavy Equipment
    • Consumables
    • Pumps
    • Featured Products
  • SAFETY
  • VIDEOS
    • Newscast
    • Drill Talks
    • Ask Brock
    • Emerging Drillers
  • EDUCATION
    • Drilling Business Insights
    • Reference Desk
    • Sponsored Insights
  • SOURCEBOOK
  • EVENTS
    • Conferences & Demo Days
    • Newscast LIVE
  • SUBMIT
    • Drillers @Work
  • ABOUT
    • Contact
    • Advertise
  • SIGN UP

Constant Pressure Systems

August 1, 2001
Robert Pelikan writes that one alternative method of providing your customers with constant pressure while extending the life of their pump is to add a constant pressure valve to a conventional water system.

During the last several years, much has been written about constant pressure systems. Most of the information has come from the manufacturers of pump systems with variable speed motors. These systems can provide constant water pressure over a fairly broad range of flow rates by electronically changing the speed of the motor, as the demand changes, to keep the pressure constant. The advantages to the end users include the elimination of annoying pressure fluctuations in their homes and an increase of motor life by reducing the number of damaging on/off cycles. Additionally, these systems may allow the use of a smaller pressure tank if space is a problem. And finally, they likely will reduce the amount of electricity used by the pump because of the affinity law, which states, "The amount of horsepower drawn by a pump motor varies by the cube of its speed."

However, variable speed systems do not come without baggage. Some are noisy, both audibly and electrically, the latter possibly effecting a neighbor's television reception. Reliability hasn't been what it should have been, and if they do break, "repair" often means replace since the problem area usually involves the electronic circuitry. Simple fixes like cleaning the bugs out of the pressure switch or filing down the points don't hack it with these systems. You will need a different set of spares on your service truck and perhaps a different service man. Even with these shortcomings, some dealers swear by these systems, so if you are the adventuresome type, jump in. Just keep your eyes open.

An alternative method of providing your customers with constant pressure while extending the life of their pump is to add a constant pressure valve to a conventional water system. These valves provide a constant pressure over a wide range of flow rates. The pressure is held constant by the use of a spring-loaded diaphragm assembly, which senses the pressure on the load side and modulates the opening in the main flow orifice as the demand varies.

Constant pressure valves are plumbed between the pump and the tank/pressure switch. The pressure on the pump side of the valve will be whatever the pump provides at deadhead, less the pressure loss due to the elevation above the pump. Make sure the piping and any valves and fittings on that side of the constant pressure valve can take the pressure.

Constant pressure valves control the system pressure on the downstream side of the valve, i.e. to the tank, the pressure switch and all points of usage in the house. Some constant pressure valves are factory-set and are not adjustable, and the others are field-adjustable, the latter having an adjustment screw to raise or lower the system pressure. What makes constant pressure valves work in a pumped water system is a small bypass orifice that allows a trickle of water to bypass the spring loaded diaphragm assembly when the household demand stops. The following example shows how they work.

Remembering that the pressure switch is on the downstream side of the constant pressure valve, let's run through a typical system cycle. Imagine a system with the constant pressure valve set at 50 psi and a 40/60-pressure switch. The pump is off and the tank is at 60 psi. When someone turns on the shower, the first few gallons come from the tank as the system pressure drops from 60 psi to the pump turn-on pressure of 40 psi. When the pump turns on - and hopefully it has more capacity than the demand - the pressure tank will begin to refill. Once the downstream pressure reaches 50 psi, the valve will begin to modulate - maintaining 50 psi as the demand varies. Finally, when everyone in the house is through using water, the demand stops, the spring-loaded diaphragm closes, but the bypass orifice lets enough water through to slowly fill the tank. The downstream pressure will slowly increase to 60 psi, at which time the pressure switch turns the pump off and we are ready for another cycle. See the pressure vs. time graph for a pictorial representation of a constant pressure valve cycle.

During this pump-on cycle, the demand could have varied from 1 gpm to 20 gpm as the usage went from brushing of teeth to showers to watering of gardens. The pump stayed on the whole time - as long as there was more than a certain gpm demand (varies with manufacturers). Life shortening pump and tank cycles were minimized, as was the amount of inrush current needed for multiple pump starts.

Constant pressure/anti-cycling valves can be a worthwhile addition to any pumped water system when trying to reduce cycling and provide uniform system pressure. They are particularly useful in systems - both residential and commercial - where there is a large variation in demand. They can save money by minimizing the number of starts and stops, which are costly, both in terms of power consumed and in motor and tank life.

Whether you opt for the variable speed pump route or the constant pressure valve method, offering constant, city-like pressure to your customers can make you a hero in their eyes and provide some differention between you and your competitors - putting a few more coins in your cords.

Share This Story

Looking for a reprint of this article?
From high-res PDFs to custom plaques, order your copy today!

Recommended Content

JOIN TODAY
to unlock your recommendations.

Already have an account? Sign In

  • geotechnical drilling rig

    6 Onsite Phrases Environmental Drillers Hate

    Here are six phrases that highlight common frustrations...
    Markets
    By: Jeff Garby
  • Wayne Nash

    Pipe Stuck? Common Causes and Solutions for Drillers

    If you have drilled for any length of time, sooner or...
    Opinions
    By: Wayne Nash
  • submersible pumps, water well pumps

    Selecting and Sizing Submersible Pump Cable

    This article helps pump installers and servicers decide...
    Opinions
    By: Bob Pelikan
You must login or register in order to post a comment.

Report Abusive Comment

Subscribe For Free!
  • eNewsletters
  • Online Registration
  • Subscription Customer Service
  • Manage My Preferences

The Driller Newscast, Episode 147: Global Geothermal Collaboration at NY-GEO 2025

The Driller Newscast, Episode 147: Global Geothermal Collaboration at NY-GEO 2025

The Driller Newscast: 21st Century Drillers | Part 1 DEMAND

The Driller Newscast: 21st Century Drillers | Part 1 DEMAND

The Driller Newscast: Coiled Tubing Drilling and the Future of Geothermal

The Driller Newscast: Coiled Tubing Drilling and the Future of Geothermal

The Driller Newscast: New York Geo Talks 2025 Conference with Hands-on Driller Education

The Driller Newscast: New York Geo Talks 2025 Conference with Hands-on Driller Education

More Videos

Sponsored Content

Sponsored Content is a special paid section where industry companies provide high quality, objective, non-commercial content around topics of interest to the The Driller audience. All Sponsored Content is supplied by the advertising company and any opinions expressed in this article are those of the author and not necessarily reflect the views of The Driller or its parent company, BNP Media. Interested in participating in our Sponsored Content section? Contact your local rep!

close
  • demo of a DM450 drilling rig during a customer factory visit
    Sponsored byGeoprobe

    Built for You: Smarter Drill Rigs, Stronger Support, Bigger Opportunities

Popular Stories

MainPhotoTwoBrothers.jpg

Two Brothers' Journey Through the Drilling Industry

Tariffs

Tariffs Shake Up the Drilling Industry

AI and Drought Concerns

AI’s Growing Thirst for Water and Power

The Driller Classifieds

COMPRESSORS

EAST WEST MACHINERY & DRILLING IS BUYING AND SELLING AIR COMPRESSORS, AIR BOOSTERS, AIR ENDS & PARTS
Company: East West Machinery

DRILL RIGS

LOOKING FOR LATE MODEL TOPHEADS & DRILLTECH D25'S
Company: Spikes’s Rig Sales

DRILL RIG PARTS

MEETING DRILLERS NEEDS AROUND THE WORLD
Company: East West Machinery

ELEVATORS

SEMCO INC. PIPE ELEVATORS
Company: Semco Inc.

GROUTERS

GROUTING EQUIPMENT - GROUT PUMPS & GROUT HOSE REELS
Company: Geo-Loop Inc.

PUMP HOISTS

SEMCO INC. - BASIC PUMP HOISTS
Company: Semco Inc.

WELL PACKERS

LANSAS PRODUCTS - INFLATABLE WELL PACKERS
Company: Vanderlans Lansas Products

WELL SCREENS

WELL SCREENS & SLOTTED PIPE
Company: Alloy Screen Works

Products

Water Quality Engineering: Physical / Chemical Treatment Processes

Water Quality Engineering: Physical / Chemical Treatment Processes

By carefully explaining both the underlying theory and the underlying mathematics, this text enables readers to fully grasp the fundamentals of physical and chemical treatment processes for water and wastewater.

See More Products

Subscribe to The Driller Newscast

Related Articles

  • Constant Pressure Systems

    See More
  • Tech Topics: Constant-pressure Systems

    See More
  • Tech Topics: Using Multiple Pressure Tanks for Larger Systems

    See More
×

Dig deeper into the drilling and water supply industry!

Build your knowledge with The Driller, covering the people, equipment and technologies across drilling markets.

SIGN UP NOW
  • RESOURCES
    • Advertise
    • Contact Us
    • Directories
    • Store
    • Want More
    • Classifieds
  • SIGN UP TODAY
    • Create Account
    • eNewsletters
    • Customer Service
    • Manage Preferences
  • SERVICES
    • Marketing Services
    • Reprints
    • Market Research
    • List Rental
    • Survey/Respondent Access
  • STAY CONNECTED
    • LinkedIn
    • Facebook
    • YouTube
    • X (Twitter)
  • PRIVACY
    • PRIVACY POLICY
    • TERMS & CONDITIONS
    • DO NOT SELL MY PERSONAL INFORMATION
    • PRIVACY REQUEST
    • ACCESSIBILITY

Copyright ©2025. All Rights Reserved BNP Media.

Design, CMS, Hosting & Web Development :: ePublishing

The Driller
search
cart
facebook twitter linkedin youtube
  • Sign In
  • Create Account
  • Sign Out
  • My Account
The Driller
  • NEWS
    • Water
    • Geothermal
    • Construction
    • Environmental
    • Mining
    • All Industry News
  • CLASSIFIEDS
  • EQUIPMENT
    • Rigs & Heavy Equipment
    • Consumables
    • Pumps
    • Featured Products
  • SAFETY
  • VIDEOS
    • Newscast
    • Drill Talks
    • Ask Brock
    • Emerging Drillers
  • EDUCATION
    • Drilling Business Insights
    • Reference Desk
    • Sponsored Insights
  • SOURCEBOOK
  • EVENTS
    • Conferences & Demo Days
    • Newscast LIVE
  • SUBMIT
    • Drillers @Work
  • ABOUT
    • Contact
    • Advertise
  • SIGN UP