Water Maker Installation

Okay, a little insomnia motivated me to expand on that water maker 'demystification' post from a few days back!

As I explained, there are many different types and sizes of water makers on the market. Some are fully contained, and and others are semi-modular or fully modular components which you can install throughout your boat. 

   
They come in varying levels of automation - from simple manual operation to fully automatic. Some of the major items they all require are:

• A raw water intake hose from a thru-hull installed below the waterline and away from turbulence
• A low-pressure supply pump that delivers sea water to the pre-filters and then feeds the high-pressure pump
• Pre-filters
• Oil/water separator
• A high-pressure pump that will develop between 800-1000 PSI to the reverse osmosis membrane
• The membrane and filtration systems
• Wiring the water maker into your AC/DC electrical system
• Plumbing to deliver fresh water into your water tank
• A series of manual or automated valves to supply a fresh water flush to the system after each use.  This is a topic that we will discuss in greater detail within an upcoming post of this water maker series.

Here’s how that Sea Recovery install went:

• On this installation, the hull I was drilling into had a double core made of foam with a thick exterior and interior fiberglass layer and a thinner sandwiched layer as shown below.  The total hull thickness was approximately 2.25".

 

• We had to make certain that the exposed foam was completely water tight. Otherwise, water could easily seep within the core of the hull and cause serious damage to the boat. I drilled a hole that was larger than required by the 1" thru-hull, then removed about half an inch of foam material from the complete circumference of the hole.  A good rule to follow: Remove the same amount of core material as the diameter of the exterior flange of the thru-hull fitting.  The thru-hull flange will then clamp down upon a solid, water-tight base.

• We then filled the new hole completely with two-part epoxy and allowed it to cure.  This process will then give us a solid base that can be drilled and not allow seawater into the foam core even if the thru-hull should someday leak.

•  Now that the epoxy has cured and we have a solid base for the new thru-hull, we could then drill our 1" hole and properly install the thru-hull fitting.

• In the photo below, we have installed the thru-hull and backer plate on the interior of the hull.  The backer plate is a rigid disc made of wood, plastic, fiberglass, or other water-resistant material that is bonded to the inside of the hull at the location of a through hull penetration. The disc adds thickness and strength, and provides a solid platform through which the seacock flange can be mechanically fastened, effectively spreading the load exerted by the seacock over the increased area of the disc. 

• The photo below shows the other side of the thru-hull on the exterior.  Always ensure that the thru-hull and the seacock are made of the same material; NEVER mix polypropylene or marelon with bronze - you risk breaking the more fragile material as you tighten down the bronze fixture.   

        

• The next step is to install a supply pump that will move the raw seawater from the seacock to the pre-filters and then on to the water maker.  The plumbing is simple and should need no explanation, however one bit of advise I would give is to ensure that the base has some sort of vibration dampening device to reduce noise and potential wear and tear.  For this installation, I simply used some rubber feet on the base of the pump.  Running electrical to operate this pump would vary according to the water maker that you are installing and the automation that is provided.  Refer to the manufacturer of the water maker to determine the correct wiring and wire size.

• In order to provide longer life to the high pressure membrane, pre-filters are needed.  Pre-filters will remove debris that could damage the water maker. Some of these filters are:

• Oil/water separation filter
• Plankton filtration to filter out debris larger than 100 microns
• Multi-media filters to filter out debris larger than 5 - 30 microns
• Mount the water maker in a secure location while also keeping in mind that service accessibility is very important.  Mounting this unit required the removal of four rubber mounts, bolting them to the shelf and then re-installing them on the water maker.  In most cases, if the water maker is a compact design (one that packages most of the major components into an enclosure) servicing it will often be difficult due to space constraints.  Modular units allow you to install the pumps and membranes in areas with easier access.
• Plumbing to the water maker is as easy as running the water hose from the last pre-filter to the inlet of the water maker or high pressure pump.
• Electrical to the water maker, in this case was simply a 230v line fed from the power distribution panel and a control panel NMEA 2000 network connection.  We also had the power feed to the low pressure feed pump installed earlier.  All of these connections were fed to a power buss located in the upper section of the water maker.  I found that I had to lay the unit down on it's side to gain access to the power buss.  The photo below gives a close view of the electrical tray.

• While the water maker is on it's side with the cover removed, I wanted to show some detail of the automatic valving and plumbing that is under the covers of this unit.  To the right of the electrical tray we have automated valves, solenoids, flow sensors and plumbing that will allow this unit to make water and automatically fresh water flush as needed. 

•  With the water maker upright and once again mounted, the covers can be replaced and we can continue plumbing.  The items that will need to be plumbed in  are:
• Product water to the fresh water holding tank
• Salt water brine which will be discharged overboard
• Fresh water flush which in this case is an automatic operation of this model water maker
• Fresh water flush consists of valving off the salt water intake to the high pressure pump and opening up a fresh water valve.  This process then pumps fresh water through the pump, lines and most important the membrane.  The fresh water flush will be plumbed in from the pressurized water system and flow through a filter before being plumbed back into the pre-filters.  In this way, every part of the water maker system will be flushed with fresh water.  The water maker will signal a solenoid valve located on the top of the filter housing when the fresh water flush cycle begins.  Note the image below:

• The fresh water flush is very important because leaving salt water in the system will destroy the membrane and reduce the life of many other components of the water maker.   Sodium Metabisulphite can also be mixed into the fresh water when the system will not be used for extended periods.  This process is known as "Pickling".

This completes the installation of the Sea Recovery system and once it is tested and put into use, it should produce 700 gallons of tasty drinking water per day.

In the next post I will cover the choice of making your own water maker system and the regular maintenance that you should expect.  Thanks for your time and attention...best wishes from Watts Up Marine Services.