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.

Refrigeration Upgrade - Digital Automation

More on the water maker installation coming soon, but today I wanted to spread the word about a product I have successfully installed numerous times in the past that will upgrade the older mechanical controls on marine refrigeration systems.  Full Gauge makes many different types of digital controls that are used in the commercial and industrial market. I have found that they also make some digital controls that work very nicely in a marine environment, as well.

Full Gauge MT 511Ril is a programmable digital thermostat that can control almost any refrigeration system up to 16 amps of power draw.  It can also be used with almost any air conditioning and heating systems with some minor modifications to the existing electrical.  It is a very cost effective way to improve temperature control and visibility.  I have found that this unit can be ordered and shipped for under $100 and can be installed with little effort.  It is easy on the eyes, can be installed anywhere on the boat with a footprint of 2.8" x 1" (71 mm x 28 mm) and a depth of 2.8" (71mm).  The MT 511Ril comes with the mounting clips to mount into a bulkhead or navigation station panel.


The major features of this control is that now the electronics can be installed anywhere and can be read easily without opening the refrigerator door.  It operates on 12-24v DC or 115v AC.  The digital sensor replaces the fragile capillary tube that older controls once used, therefore removing the distance constraint that the rotary controls once had.  It has the ability to control the temperature from  -58 to 211degrees F and also gives you an adjustable temperature differential between compressor-off to compressor-on.  This temperature differential can mean significant power savings when you are out to sea.

Another new model that I have just ordered for stock is the MT 511C, it has all of the same qualities and features yet is much easier to mount due to it's round hole pattern.  See the photo below.

Other temperature controllers made by Full Gauge also sense the build-up of frost on the evaporator.  These devices have two temperature sensors and compare the temperature differential between the evaporator plate and the freezer/refrigerator box.  When the temperature difference is too great, the unit will then shut off the compressor and wait for the temperature of the plate to get above freezing which will melt the ice.  Once it senses a "no ice" condition, the compressor continues to operate normally.

The MT 511 is a device I would recommend to anyone that has the older non-digital controls on their refrigerators, freezers, heaters and air conditioning units. Have you had any experience with this product?  Any stories to share regarding your older temperature controls?  Post them here!

Demystifying the Water Maker

Although Watts Up Marine Services focuses primarily on electrical, air conditioning/heating, refrigeration and electronic navigation systems, I get a lot of questions from folks about water makers. In a ‘former life,’ I worked with filtration and RO water systems that are associated with giant cooling towers in large buildings, power plants and data centers, which simplified the concept for me.  There seems to be some confusion around how water makers work, so I thought I’d take the opportunity through my latest water maker installation project to demystify them for my readers.

Reverse Osmosis (RO) Water Makers - How do they work?

Reverse osmosis is the process of forcing filtered sea water through a membrane at a very high pressure – about 800 pounds per square inch – which removes salt ions and other impurities, retains that solute on one side of the membrane and collects fresh water on the other side of the membrane. The membrane filters out most of the salt as well as bacteria, viruses, and other contaminants.   Further filtration of the fresh water occurs only to improve the taste and to adjust the pH.

I am installing a water maker on a 52-foot power boat that will be based in the Bahamas at a private island where there is no fresh water available, so the ability to take sea water and turn it into fresh water for showering, drinking and cooking serves a critical function. This Sea Recovery, Aqua Matic water maker is able to provide 29 gallons of fresh water per hour: 700 gallons per day.  Salt rejection for these units averages 99.4%.  That's probably better quality water than what comes out of our taps at home!

The keys to its reliability are the proper planning, initial installation and the correct regular maintenance.  There are several things you must take into account:

• How much fresh water will you need per day? Per hour?  How much water you need will determine the amount of power you need to supply your water maker.
• How much power consumption you can provide, and what type of power -- 12/24v D/C or 115/230v A/C?  The more water you need, the more power it will require.  If a generator is available, this issue becomes much easier to resolve. But if you are limited in the power you can supply, you may need to rethink your water consumption requirements.
• Where in the world will you be, and can you get spare parts?  Do you need a system with an absolute minimum of proprietary parts on the machine, so no matter where in the world you go, the machine can be serviced and repaired using parts and supplies that can be sourced easily? Something to be considered if you want to romp in the less-developed parts of the world.
• How much automation do you require?  Do you need a fully automatic system that will flush the membrane on a regular basis or make water as needed or do you just need one that will make fresh water?  You should weigh your willingness/ability to perform manual functions before choosing your system.
• How much room do you have for a water maker?  There are two types of water maker systems: compact or modular.  Compact systems have most of the major components enclosed within one frame.  The only remaining items that would require mounting somewhere in the boat would be the booster pump, which supplies raw water to the compact water maker, and some pre-filters.  If you have no room to mount a compact system, you may opt to go modular, which is comprised of individual parts that can be installed in different parts of the boat when space is an issue.
• How much can you spend?  The amount of water you will require and the automation you select will be reflected in the investment you make.  Don't always purchase the unit that is most cost effective with the initial purchase, the cost in maintenance and consumables might surprise you later.

Once you select a system, you then have to consider installation.  Here are the major points:

• Where to install the raw water intake?  It must be well below the waterline on the hull, away from any turbulence while underway. Air bubbles caused by turbulence can be pulled into the intake and “explode,” -- cause cavitation inside the high pressure pump. This can deteriorate the metal surfaces inside the pump and cause pump failure.
• How is your boat's hull constructed? When installing the intake, the number one thing to avoid is allowing sea water to seep into the many layers of your hull.  If your hull is fiberglass with a foam or balsa core, your intake installation must include steps to seal the area around the intake to ensure that if the thru-hull someday begins to leak, it won’t saturate the material sandwiched between your fiberglass layers, causing major hull damage.
• Where do you fill your fresh water tank? You will want to consider where your tank fill is located so you can properly plumb it to fill with fresh water.
• Where does your water tank vent? Some boats' water tanks vent into the bilge, so if your water maker overfills the tank, you fill your bilge. An automatic shut-off may be necessary.
• Where do you drain the waste?  The brine waste that is rejected by the membrane has to go somewhere! Directly overboard is best, so figure that you'll have to plumb some sort of overboard drain.

My next blog post will describe, step by step, the installation of the Sea Recovery water maker, with pictures, so I hope you check back in for more information.  Meanwhile, feel free to post any of your questions about water makers and I’ll be happy to respond. See you soon!