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Geothermal Rescue – Open Loop Water Turns Acidic

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This geothermal rescue project involved an open loop geothermal system, corrosive water, and saving multiple heat pumps from premature failure.  Open loop systems use well water to convey the Sun’s energy from the Earth to the geothermal heat pumps inside.  Because heat pumps need up to 3 gallons per minute per ton of capacity, the required flow of water can quickly become quite high, especially when the heating or cooling load is high.  For example, if the average geothermal installation is 10 tons of cooling or heating capacity, that would mean a flow of 30 gallons a minute for every minute the heat pumps were on providing heating or cooling.  A normal potable well will produce 15 gallons a minute, so needing 30 gallons per minute for days on end is a prodigious amount of water.

This is the primary reason that open loop geothermal systems are fairly rare and that most people that install geothermal systems that are closed loop that do not use potable water.

IMG_6388We have seen that the removal of large amounts of water from the water aquifer by an open loop geothermal heat pump system can often lead to water quality changes – most often the water becomes more acidic.  That happened in this geothermal system – the heat pumps were going off on various faults all tied to inadequate flow – we took apart the main loop circulator pump and found that the impeller and shaft inside the circulator had been dissolved!  We tested the water and found that it was very acidic at pH 5!  This was very dangerous to the heat pumps and piping – any leaks that might develop would NOT be covered by the manufacturer’s warranty.   As we disassembled more of the system, we discovered more parts had been eaten away – such as this metering assembly.

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We developed a plan for the homeowner – we would install a large plate and frame heat exchanger to separate the outside water (which was now corrosive and acidic) from the clean inside geothermal water that served the heat pumps while still transferring heat between the two fluids.  Here we can see the stack of stainless steel plates that will be tightly squeezed between the two plates when the nuts are tightened – each alternating plate of stainless steel has inside water, the other plates have outside water.

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This project required some reworking of the mechanical room to accomodate the new heat exchanger.  Dave Sprague spent considerable time laying out where the heat exchanger would go.

 

 

 

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Dave carefully located the anchor points and the heat exchanger’s back plate was installed.  Each plate weighed 200 pounds.

 

 

 

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The stainless steel inner plates were assembled and the front plate tightened up to the correct torque specs.  Based on the water quality, we would expect to disassemble this heat exchanger every other year to scrub the individual stainless steel plates with a nylon bristle brush and water.  Stainless steel was chosen for its resistance to the corrosive outside water.

 

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The existing geothermal piping was reworked so that we could install the heat exchanger as the separator between the outside water (copper pipes on the left side) and the inside loop water (copper pipes on the right side).  The large horizontal ball valve in the upper part of the picture is a bypass which we use when cleaning is necessary.

 

 

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The final installation included a chemical feeder to neutralize the inside water until all traces of outside corrosive water were removed.  The installation of this plate and frame heat exchanger converted this failing open loop geothermal system into a reliable hybrid open/closed loop geothermal system.  The corrosive water caused by the change in the aquifer would no longer be able to damage the inside geothermal heat pumps.

 

Our goal is to be Martha’s Vineyard’s premier plumbing and HVAC shop – we appreciate the opportunity to show you some of our work.

About Nelson Mechanical Design (NMD)

NMD is Martha’s Vineyard “green” mechanical contractor, designing and installing just about anything to do with heating, cooling, domestic hot water, water treatment, or controls: geothermal systems, heat pump systems, fossil fueled systems, air conditioning, solar hot thermal, plumbing, well water service, water treatment, ventilation, and internet accessible control systems. In the residential world, they designed and installed the mechanical systems for…

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About Your Equipment and System

About Your System: Each of these menu topics describe the components of  the various heating, cooling, ventilation, and plumbing systems that we install and service.  Our goal is to make this part of our website a resource to better inform our customers about their equipment and systems.  When you call for service, we hope the information will assist you in describing what…

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Air Conditioning 101

The descriptions and pictures below are designed to foster a basic understanding of the parts of your air conditioning system.  When you call for service, we hope they will help you to identify those parts of your system that may need service.  When you receive an invoice from us, we hope the information below will help clarify which parts and systems we…

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Air Conditioning Installation, Service, and “Rescue”

Installation: For the installation of air conditioning systems, please start the process by contacting Dave Sprague in our new construction department to discuss your goals. Some things to consider: – How cold would you like the house to be during the summer?  We have seen customers interested in progressively colder inside temperatures – ten years ago 74 F was the norm and now folks…

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Boiler & Hydronic System Installation, Service, and “Rescue”

Installation: For the installation of boilers and hydronic systems, please start the process by contacting Dave Sprague in our new construction department to discuss your goals. Some things to consider: – Do you have propane piping already installed at your home?  We do not work with fuel oil. – What are the venting options (existing chimney, sidewall termination, chimney liner, etc.) – What…

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Contact Us

If you are a new customer in need of service, click here to expedite the process by filling out our online service intake form. If you are building a new home or renovating your existing home, click here to expedite the process by filling out our online new construction intake form. Nelson Mechanical Design (NMD) has a new phone system! After dialing 508…

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Contractor HVAC Fillable Form

Fill complete the form below if you’re interested in an HVAC project

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Control Systems Installation, Service, and “Rescue”

Installation: For the installation of new controls systems,  please start off the process by contacting Marlon, our service manager, to discuss your goals: Some things to consider: – What systems (heating, cooling, ventilation, plumbing, etc.) do you wish to control.  We have experience with controlling just about any mechanical system. – Do you wish to add or separate heating or cooling zones?…

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Daikin Altherma Heat Pump Installation

Unfortunately, Daikin appears to have withdrawn their support for the Daikin Altherma in the United States due to low sales figures.  We have a few on the Vineyard that we have installed and we have been factory trained to service these units.  Daikin still has one tech that specializes in Altherma service and setup.  Contact our service department if you wish to…

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Emergency Services

Our emergency services are for our loyal customers of record.  If you are not a customer, please call us during our business hours to become one. Emergency contact: 508-696-3120 (24 HOURS A DAY OUTSIDE OF BUSINESS HOURS) Emergency hours:  after 4 pm Monday- Friday, anytime outside of business hours Saturday & Sunday Master Technician, $180.00 Technician, $165.00 Holiday hours: National Holidays (observed)…

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Equipment Installation Examples

These pages provide installation examples of the many different types of equipment we install in businesses and homes on the Vineyard.

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Featured System Installations

These pages show some of our finest system installations and “rescue” projects  in businesses and residences on the Vineyard.

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Frequently Asked Questions

The menu topics are representative of questions we have answered about the equipment and systems we install and service. While the laws of physics haven’t changed lately, technology is evolving constantly, and our role at NMD is to understand how this evolution affects our systems and customers.  We are constantly learning about new techniques and approaches to HVAC and plumbing systems so that…

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Furnaces & Ductwork Installation, Service, and “Rescue”

Installation: For the installation of new furnaces and forced air ductwork,  please start the process by contacting Dave Sprague in our new construction department to discuss your goals. Some things to consider: – Do you have propane piping already installed at your home?  We do not work with fuel oil. – What are the venting options (existing chimney, sidewall termination, chimney liner,…

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Geothermal – Radiant – Rescue Team

This team specializes in service, installation, and “rescue” of the more advanced HVAC systems on the Vineyard.  At the head of this department is Brian Nelson,  who established NMD with his business partner Dave Sprague in 2004. Since then, Brian has supervised the “rescue” of over a dozen intricate HVAC systems that were underperforming, inefficient, or constantly trouble-prone.  Using his engineering background (M.S.M.E. from Boston University)…

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Geothermal System Installation, Service, and “Rescue”

Installation: For the installation of geothermal systems, please start off the process by contacting Dave Sprague in our new construction department to discuss your goals. Some things to consider: – How cold would you like the house to be during the summer?  We have seen customers interested in progressively colder inside temperatures – ten years ago 74 F was the norm and…

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Heat Pump & Mini-Split Installation, Service, and Rescue

Installation: For the installation of heat pumps and mini-splits, please start the process by contacting Dave Sprague in our new construction department to discuss your goals. Some things to consider: – Mini-splits are great for heating or cooling one room or when ganged together can handle an entire building.  Heat pumps are typically used with ductwork. – How cold would you like the house…

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Heat Pumps (Mini-Split)

Mini-splits Heat Pumps are air source heat pumps that have revolutionized heating and air conditioning around the globe – they are the fastest growing and largest part of the global HVAC market.    They can heat a room or a whole house at half the operating cost of propane heating and provide cooling and dehumidification (“dry mode”) too. We have installed and serviced all…

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Homeowner HVAC Fillable Form

Fill complete the form below if you’re interested in an HVAC project

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HVAC

This page will redirect to either ‘HVAC – Homeowner Team‘ or ‘HVAC – Contractor Team‘

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HVAC – Contractor Team

This team installs HVAC systems for contractors and architects in both new and remodel projects.  At the head of this department is Matthew Rivers, who has been with NMD for over five years.   Matt and his team specialize in Mitsubishi Hyper Heat and Bryant Evolution ducted systems, Renewaire ERV ventilation systems, UltraAire whole home dehumidifiers, and other high efficiency product lines. Matt understands…

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HVAC – Homeowner Team

This team installs HVAC systems for homeowners in both new and remodel projects.  At the head of this department is Tom Neadow,  who has been with NMD for over seven years.   Tom and his team specialize in new and replacement furnace and boiler systems, ducted HVAC systems, and retrofits to existing HVAC installations. Tom coordinates closely with Dave Sprague, co-owner of NMD, to ensure that…

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Indoor Air Quality & Humidification Installation, Service, and “Rescue”

Installation: For the installation of humidifiers and indoor air quality systems, please start the process by contacting Dave Sprague in our new construction department to discuss your goals. Some things to consider: – What is the size of the area that you would like to humidify?  Water vapor disperses throughout a home until equilibrium is reached.  This means that it is hard to humidify…

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Info Sheets

Below are links to PDFs we have created to provide information for various services we offer      5 Steps Before Calling                                       HVAC Maintenance                        Preventative Maintenance Overview       Preventative Maintenance Services   …

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Installation of Water Treatment Systems

As licensed Massachusetts Master Plumbers, we are allowed to design, install, and modify water treatment systems.  As necessary, we will secure a plumbing permit for the installation of the water treatment system and arrange for its inspection. After performing water testing, we will determine the best type of treatment system to install in your home. If you have an outdated existing system we can…

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Installing a new plumbing or HVAC System?

Are you installing a new HVAC system or plumbing in your home or business and need help from NMD?  Please fill out the form below and our new construction team will contact you shortly.   Thank you!

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Interested in Mini-splits?

Please fill out our mini-split intake form to jump start the process of getting mini-splits installed in your Vineyard home or business.  Everett Walsh will contact you shortly after receiving this form.  His email is projects@nmdgreen.com 

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Internet access to your home

Carrier Infinity Remote Access Touch Control (Wi-fi Touch Screen): http://www.carrier.com/residential/en/us/products/thermostats/systxccitc01-a/ “The Infinity Touch control is the key to unlocking your comfort potential. It’s also the brains behind a Greenspeed™ intelligence system. As part of a complete Infinity, communicating system, this one control can manage temperatures, humidity, ventilation, airflow, indoor air quality and up to eight zones. If your system includes a heat…

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Internet and Wifi Thermostat Installation, Service, and “Rescue”

Installation: For the installation of internet and wifi thermostats, please start the process by contacting Dave Sprague in our new construction department to discuss your goals. Some things to consider: – How many thermostats are existing in the home and what equipment do they control? – If they control equipment from certain brands then there may be multiple thermostat options. – What areas of…

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Island iron issues

Click on the image at left to scroll through some examples of iron issues commonly found on the Vineyard.

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Mini Split Team

This team installs mini split systems for homeowners and contractors in both new and remodel projects.  At the head of this department is Nick Lucas,  who has been with NMD for over three years.   Nick and his team specialize in Mitsubishi mini splits systems of all sizes – single zone, multi zone, branch box, and integrated and internet controlled. Nick coordinates carefully with the homeowner, caretaker, and electrician…

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Mini-split Case Study: One inside wall unit to one outside unit

In this case study, we will explore the design and installation of a mini-split system with one inside wall head and one outside wall unit.

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Need HVAC or Plumbing Service?

Are you in need of service on your HVAC system or plumbing?  Please fill out the form below and our service manager will contact you.  Thank you!

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Need HVAC Preventative Maintenance?

Have we installed a heating and cooling system (ducted or mini-split) at your home but haven’t provided you with preventative maintenance to keep it in top notch condition?

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Need Water Treatment Service ?

We offer extensive water treatment service options.  Please visit our water treatment pages on this site for more information. Thanks!

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New Construction Design Process – Heating, Cooling, and Ventilation

  We have built our new construction department on the foundation of our mechanical design abilities. This is one of our favorite services to offer – we can calculate and specify exactly what heating, cooling, ventilation, and indoor air quality system your home or building requires to be comfortable and energy efficient.   Mechanical systems will not operate at their highest efficiency…

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NMD Showcase

Featured System Installations Projects for Non Profits and NMD Concepts Equipment Installation Examples

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Plumbing and DHW Installation, Service, “Rescue”

Installation: For the installation of plumbing and domestic hot water systems, please start the process by contacting Dave Sprague in our new construction department to discuss your goals. Some things to consider:  Is this a new construction plumbing project or a retrofit?  Plumbing fixtures have become more and more specialized and their selection and installation require a great deal of care and attention…

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Plumbing Fillable Form

Please complete the form below for Plumbing Installations

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Plumbing Team

This team installs plumbing systems for homeowners and contractors in both new and remodel projects.  At the head of this department is Paul Vertefeuille,  who has been with NMD for over six years.   Paul is Master Plumber, licensed in Massachusetts, and is able to design and install rough and finish plumbing in both residential and commercial settings. Paul coordinates closely with Dave Sprague, co-owner of NMD,…

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Preventative Maintenance

Preventative Maintenance: All mechanical systems need maintenance to operate correctly during their expected lifespan.  We offer a wide range of preventative maintenance services based on  the manufacturer’s guidelines and adjusted for the Vineyard environment.   Some of these services are optional and depend on the occupancy of the home or business; others are essential for the correct operation of the equipment. Please…

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Preventative Maintenance Flat Rate Pricing

To you, our valued customer, we have put together some simple flat rate pricing for the preventative maintenance of your plumbing and HVAC systems in your home.  We realize that some customers want a brief check on all systems, while other customers need or require a visit that is more in depth.  The packages below will cover this wide range of preferences. …

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Privacy Policy

Nelson Mechanical Design, Inc. does not share client contact information or information about their properties.  We respect our client’s privacy and the security of their personal information and homes.

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Products

Our role is to install and service the most reliable and modern heating, cooling, ventilation, air quality, plumbing, and water treatment equipment available.  We serve as an essential filter for our customers – determining what innovations are worth pursuing and what new products we can stand behind.  This requires a constant commitment to training the NMD team so that we know how…

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Projects for Non Profits and NMD Concepts

We support the efforts to build affordable housing here on the Vineyard.  We have donated time and money to the various housing groups to aid their important work to create long term stability through affordable housing.  Some of our recent affordable housing installations are shown below. Over the years, we have developed some concepts that merit further investigation.  As we move towards…

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Resources

Frequently Asked Questions: The menu topics are representative of questions we have answered about the equipment and systems we install and service.   While the laws of physics haven’t changed lately, technology is evolving constantly, and our role at NMD is to understand how this evolution affects our systems and customers.  We are constantly learning about new techniques and approaches to HVAC…

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Service Fillable Form

Are you in need of service on your HVAC system or plumbing?  Please fill out the form below and our service manager, Marlon Dwyer, will contact you.  Thank you!

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Service Team

Our service team is ready to help our customers service their HVAC, plumbing, water treatment, ventilation, and control systems around the clock.  Our normal service hours are from 8 am to 4 pm.  After that we have on-call personnel to attend to our customers’ emergency needs.  If you have a need for service after our business hours, please call 508-696-3120 and follow…

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Services

Installation, Service, and “Rescue” We offer installation, service, and “rescue” for practically anything and everything involving heating, cooling, ventilation, indoor air quality, plumbing, water treatment, and internet access in your home or business.  We have installation teams that focus on new construction projects (new air conditioning, heat pumps, ducted furnaces, boilers, mini-splits, etc., etc.,),  we have service teams that are able to troubleshoot,…

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Solar Hot Water Installation, Service, and “Rescue”

Installation: For the installation of new solar hot water systems,  please start off the process by contacting Marlon, our service manager, to discuss your goals: Some things to consider: – Will the solar system heat domestic hot water? –  Will it be used for space heating? –  Solar hot water panels are either flat-plate collectors or evacuated tube collectors.  Each approach has…

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Terms & Conditions

Please review the following items about our billing process, payment, service teams, and other important aspects of NMD.  Once you accept these Terms and Conditions (by clicking Submit at the bottom), we will be able to assist you with your service needs or a new plumbing and HVAC project.  

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Thank you for your inquiry!

We appreciate your interest in our services and installations!  We look forward to working with you towards meeting your HVAC and plumbing needs.  Our goal is to respond quickly to your query – we try to respond via phone or email the same day for service queries and within a few days for new construction projects.   If you are inquiring about…

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The History of Water on Martha’s Vineyard

Living on Martha’s Vineyard comes with many wonders and struggles.  Water quality can be one of those struggles.  The water on the Vineyard varies tremendously based on the different layers of rock and sediment left by the receding ice sheet 10,000 years ago.  So levels of iron, manganese, and other minerals as well as acidic or basic water can vary dramatically from…

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Water Softener Systems (Brine Tanks)

There are a few instances where you may need a water softener, sometimes referred to as a brine tank, added to your treatment system. If you have an acid neutralizer currently installed and you are suffering from soap scum or scaling you may need to have a softener added. When installing new acid neutralizer systems we generally install a softener to give…

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Water Treatment Installation and Service

We are starting our Water Treatment Promotion!  Learn more.… The History of Water on Martha’s Vineyard Living on Martha’s Vineyard comes with many wonders and struggles.  Water quality can be one of those struggles.  The water on the Vineyard varies tremendously based on the different layers of rock and sediment left by the receding ice sheet 10,000 years ago.  So levels of…

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Water Treatment Preventative Maintenance

Your water treatment system works hard to provide you with clean safe drinking water. It is a “living” system, that means that it is constantly getting fresh water from your well that has a unique make-up, each system is different and handles your specific water in different ways. It is important that you get regular maintenance, whether it be iron or acidic water…

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Water Treatment Promotion Page

This is our Water Treatment Promotion!  Please fill out the info below to start the process with NMD.

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Water Treatment Systems for Acid Neutralization (Low pH)

All of our water treatment products are safe and natural. Your acid neutralization system will raise your ph by using Calcite. Calcite is a naturally occurring calcium carbonate media, otherwise known as Georgia Marble. One of the advantages of Calcite is its self-limiting property.  When properly applied, it corrects pH only enough to reach a non-corrosive equilibrium. It does not over correct under…

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Water Treatment Systems for Iron Removal and Reduction

For customers suffering from issues with iron in their water, we offer the PROVECTR Plus line from Watersoft. All our products and are safe and natural, providing a chemical-free water treatment. A typical iron system will include an air compressor: this injects air into your water and allows the ferrous iron to oxidize and form ferric oxide, which is then a larger…

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Water Treatment Team

This team services and installs water treatment systems in both residential and commercial settings.  Our two water treatment experts are Nick Rivers and Nick Moreis.   Their team has received factory training from Watersoft, the leading water treatment manufacturer in the US. The water treatment team performs periodic maintenance on existing systems and “rescue” work on systems that are not working correctly.   Typically…

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What We Test for in your Water

Your water should be crystal clear and free from chemicals, odors, bad tastes and hardness. However, water quality varies from home to home, and there are many common water problems that can cause your water to appear cloudy, have a bad smell or taste, stain and water-spot fixtures, or even shorten the life of your pipes and appliances. Testing your water is…

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Who We Are

Check here for all that is new at Nelson Mechanical Design.  You will find our latest promotions, Constant Contact emails, articles about us that have appeared in local and national press, articles about our team members, and features on our innovations in the HVAC and plumbing fields.

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Why Choose NMD for your HVAC project with a contractor, builder, or architect?

When you call the HVAC-Contractor team at NMD for a quote on a new heating and air conditioning system for your new home or renovation project, the follow steps happen: Matt Rivers and David Sprague will arrange a site visit to your property or office to review the plans for the project and discuss and what the client needs are in terms of…

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Why Nelson Mechanical Design?

David Sprague and Brian Nelson started Nelson Mechanical Design in 2004 with a commitment to Martha’s Vineyard – we will provide the best service to our customers,  provide stable, long term careers to our people, and support the fabric of our island home.

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