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Geothermal 101

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The descriptions and pictures below are designed to foster a basic understanding of the parts of your geothermal 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 worked on during our service visit.

There are two fundamentally different forms of geothermal heating – “Sun based” geothermal and “Hot rock” geothermal.

“Sun based” geothermal – the type we install, service, and rescue – is truly a solar energy machine – the heat from the Sun heats the first 30 feet of Earth in a seasonal fashion and the remaining 300 to 500 feet in an annual fashion.

“Hot rock” geothermal starts at about 1000′ and goes deeper and utilizes the heat generated by the radioactive decay of the elements in the interior of the Earth.  (Interesting to ponder that the Earth was so “hot” from radioactivity that life could not begin on the surface until at least a billion years of decay had elapsed!)

Because we are using the Earth and the Sun, we need to somehow connect our geothermal system to the Earth.  The mode of connection – closed loop with buried black plastic pipe, closed loop with buried copper tubing, open loop with supply and return water wells, pond source, and ocean source – are all discussed in our geothermal page in Products.  Here we will discuss the particular components of the geothermal system.

Fielder geo trench w geo ball slinkee rolled out Jan 2011

 

The geothermal field comes in many different types but one of the most common is the horizontal “slinkee” closed loop arrangement of black plastic pipe (same type of pipe as we use for buried water wells).

 

 

 

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The geothermal loop circulator is the heart of the system that connects the outside geothermal field with the inside geothermal heat pump.  It needs to be large enough to handle the largest heating and cooling load that might be encountered during the winter or summer.

 

 

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We use an air separator to remove air bubbles from the geothermal supply water, just like we do with boilers, solar systems, and hydronic heating systems.

 

 

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We also use an expansion tank to accomodate the seasonal changes in geothermal supply temperature and the accompanying change in pressure.

 

 

 

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Each geothermal heat pump is connected with the loop circulator and outside geothermal field via supply and return piping.

 

 

 

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Each geothermal heat pump is connect to the supply and return piping with stainless steel flex connections (stainless braided hoses) that help to reduce the transmission of noise and vibration from the heat pump to the piping.

 

 

 

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Most geothermal heat pumps are “water to air heat pumps” which means that they are connected to the geothermal “water” as a source for heating and cooling via the heat pump and to the “air” delivery system of ducts in the house as we would find in a furnace or air source heat pump.

 

 

 

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The other common type of geothermal heat pump is the “water to water heat pump” which means that it is connected to the geothermal “water” as a source for heating and cooling via the heat pump and to the “water” delivery system of hydronic heat.  Typically the heat pump is connected to a radiant heating system – the water temperature limit of 120 F from a heat pump is fine for radiant floor heat but not high enough for baseboard fin tube or radiators.

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In all geothermal heat pumps, there are two heat exchangers; the first one is between the Earth (geothermal water) and the refrigerant in the heat pump. (water to refrigerant heat exchanger)

 

 

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This heat exchanger is connected to the compressor which increases the temperature and pressure of the refrigerant.

 

 

 

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The refrigerant is metered by the thermostatic expansion valve (TXV) which regulates the flow of refrigerant into the evaporator.

 

 

 

 

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The flow of refrigerant can change direction, based on the position of the reversing valve.  This valve determines if the heat pump is in cooling mode or heating mode.

 

 

 

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The contactor is the large relay that sends power to the compressor when there is a call for heating or cooling.

 

 

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The control board determines the operation of all parts of the heat pump by interpreting the commands from the thermostat.

 

 

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The refrigerant rejects or absorbs heat from the inside space through the refrigerant to air heat exchanger (also known as the evaporator coil or condenser)

 

 

 

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The blower motor and blower wheel (squirrel cage) pull the air through the air filter and force it through the heat exchanger and back up to the living space.

 

 

 

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The condensate pump is necessary to remove the collected water from the inside coil when in cooling mode.

 

 

 

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The thermostat regulates the temperature of the living space by cycling the blower, compressor, and loop circulator on and off.  The latest heat pumps are able to modulate the speed of all three of these parts with the resultant increase in efficiency, comfort, and even temperature distribution.

 

 

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The heat pump part of the geothermal system is usually powered by a double pole circuit breaker in the breaker box.  An extremely common cause of no heating or air conditioning in a geothermal system is a circuit breaker in the off position.

 

 

Our goal is to be Martha’s Vineyard’s premier plumbing and HVAC shop – we appreciate the opportunity to service, install, and “rescue” your geothermal system!

 

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

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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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Emergency Team

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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 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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Geothermal Team

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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

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HVAC

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HVAC – Contractor Team

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HVAC – Homeowner Team

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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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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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Mini Split Team

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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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Our Teams

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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

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Plumbing Team

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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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Rescue Team

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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 with 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

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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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What’s New

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 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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