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Framed Watermaker Operations Manual

Rainman Technology Pty Ltd
49 Orchard Road
Brookvale, NSW 2100
Australia

www.rainmandesal.com

support@rainmandesal.com

Introduction

This instruction manual is for our family of AC electric powered framed watermakers. Although power requirements and membrane configurations can vary between the models, the operations are largely similar across the range.

Additional technical information can always be found on the support section of our website.

Several icons are used throughout the text to indicate the purpose of the particular paragraph:

The 240L icon means the paragraph applies specifically to the largest 240lph Torrent system.

The 140L/100L icon means the paragraph applies specifically to the 140lph and 100lph units (either 230VAC/50Hz or 115VAC/60Hz).

This icon indicates a specific warning, indicating actions to be taken to ensure safety or protection of your watermaker.

Understanding Your System

Rainman Concept

The Rainman framed watermaker is a single unit that consists of an electric motor, two pumps, prefilters, multiple reverse osmosis (RO) membranes, and an autoflush system. The system lifts seawater, filters sediments out, then put it under pressure past the RO membranes. These membranes extract a small amount fresh water from the filtered seawater stream and diverts it to the vessel’s tank, allowing most of the water and all of the salt to pass out as waste.

The basic configuration for Rainman Framed Watermaker

Desalination Basics

Desalination is relatively simple in principle.

The Rainman watermaker operates through a process called reverse osmosis (RO). In its most simple terms, the system draws seawater up, filters out sediment and particulates, then puts the clean seawater under high pressure to pass through an RO membrane. The RO membrane is a semi-permeable polyamide thin-film composite.

A traditional sediment filter, like our prefilter, works by passing all the water through it. The fine construct prevents larger particles from getting through and they are captured on the filter material. When a lot of particles have been captured on the filter and it’s dirty, you change it.

In contrast, the RO process passes filtered seawater across the membrane surface at high pressure. Keeping the description simple, the system is essentially extracting a small percentage of the freshwater from the seawater stream. The majority of the water and all of the salt continues in the flow and out the brine waste water hose. The salt does not accumulate on the membrane, which is why RO membranes do not need to be cleaned or replaced regularly.

Detailed Schematic

An impeller lift pump draws seawater up to the pressure supply unit (PSU) and creates positive pressure for the high pressure pump.
The pre-filter removes particulates larger than 5 microns from the seawater.
A high pressure pump pressurises the system for the reverse osmosis membranes to operate.

The relief valve only opens if the control valve is closed excessively.
A high pressure hose carries filtered seawater to the reverse osmosis membranes.
Multiple membranes are connected in series (double or triple RO membrane configuration).
The pressure control valve at the end of the system is used to set system pressure to approximately 55 bar (800 psi).
Brine water is released to the sea while fresh water is routed to your drinking water tank.

Operating The Watermaker

Preparing To Make Water

A number of items should be in place in preparation of making water.

Be located in non-polluted water.
Ensure the intake valve near the intake strainer is open.
Sufficient power should be available to start and run the motor.
Pressure control valve should be fully opened.
Diverter valve should be set to “DIVERT”.

Making Water

Three steps are required to begin making water via the manual control panel.

Turn the switch to "ON" position.

The motor and pump will start running, with all water going out the brine waste hose.

Slowly increase pressure by turning the pressure control valve clockwise. Continue building pressure until either

A) The system reached 55 bar (800psi).

or

B) The product water flow rate reaches no more than 10% above the rated flow of your Rainman model. This applies in brackish water.

This should be periodically monitored for required adjustments.

When the water quality LED indicates green or amber in colour, switch the diverter valve from "DIVERT" to "TANK".

The "WATER QUALITY" indicator is a tri-colour LED. Upon system startup, the LED should be red. After pressurising the system and the water quality improves, the LED should turn amber or green. This indicates good water quality.

If the LED does not move from red colour, there is an issue suggesting the TDS (total dissolved solids) is high. This usually indicates a reduced total flow rate, but may also suggest a worn membrane.

The low pressure gauge indicates the pressure at the prefilter. If the pressure fails to get into green zone of the gauge, a blockage is indicated. Usually this is related to a clogged prefilter that requires changing. However, it may also indicate a worn impeller or blockage upstream from the lift pump.

Shutting Down Watermaker

Shutting the watermaker down requires reversing the steps of starting it up.

Move diverter valve to "DIVERT".
This stops product water going into your tank, sending it overboard as waste.

Slowly decrease pressure by turning pressure control valve anti-clockwise. Stop decreasing pressure when the pressure gets to 0 bar (0 psi). There is no need to completely open the valve.

Turn the power switch to "AUTOFLUSH" position.

A motor valve will open after fifteen seconds, allowing the house water pump to flush fresh water through the activated carbon filter and through the membranes. The blue "FLUSH TIMER" LED will be solid blue during this cycle.

After the autoflush cycle completes, the blue "FLUSH TIMER" LED will flash sequences of seven times. This indicates the next autoflush cycle will be in seven days. As the timer counts down, the LED indicator will flash fewer times, once for each day until the next cycle.

If the watermaker is run prior to the next flush, the system will flush upon shutdown and reset the timer.

Quick Reference

After understanding the operation in detail, a quick reference card may be useful.

Never allow water containing chlorine to enter your watermaker. That includes town or tap water, which contains chlorine, or water from a vessel’s tanks, which may also contain chlorine. Chlorine damages RO membranes.

Never run the unit dry. It will damage the pumps.

Switching off the watermaker while system is under pressure will cause pressure shock to the membranes and may damage them.

Never exceed 58 Bar (850 psi). If you over-tighten the pressure control valve, the relief valve in the PSU will release and water will recirculate within the high pressure pump. This prevents damage to the RO membranes from excess pressure. However, prolonged operation of the relief valve can damage the unit.

Switching off the watermaker while system is under pressure will cause pressure shock to the membranes and may damage them.

Gradually close the pressure control valve on the reverse osmosis unit by turning clockwise until the pressure gauge reads 55 Bar (800 psi). The correct pressure is indicated by the dark green area on the pressure gauge dial. For maximum membrane life, take about one minute to build to full pressure. Within 15 seconds water will start flowing out the white product hose.

Note: the clear liquid inside the pressure gauge is glycerine. This is to reduce vibration inside the gauge and ensure long and reliable service. It is normal to see a large bubble inside the gauge.

If you are using your watermaker for the first time, run for at least half an hour to flush all preservatives from the system.

Product water flow will vary depending on several factors, including temperature and salinity. Warmer or lower salinity water will lead to higher levels of product water output. Natural membrane variability and other factors will play a role in product water output.

As a guideline every degree Celsius increase in water temperature, product water flow increases approximately 3%.

Desalinating While Under Way

Your Rainman watermaker can be operated while under way. Ideally, your unit should be installed and connected to a through hull that is always underwater at all angles of heel and roll. In this case you can operate your system as per the normal procedure outlined above.

Depending on hull shape, speed, and the sea state, air bubbles can find their way to a through hull fitting even if it is well below the water. Some boats, speeds and sea states are not suitable for making water underway.

Several Rainman owners have been successful in using their portable watermaker while under way without a dedicated through hull by trailing the intake hose in the wash at the stern of their vessel. To prevent air working into the system, customers have used either weights or a down pole to hold the intake below the surface.

Slide the intake cap up the intake hose and securing it on board the vessel so that the end of the intake hose can sink sufficiently below the surface.

Do not use the detachable suction strainer when towing the intake hose.

If the intake hose is sucking air, the membranes may be damaged.

Another method of using a portable system whilst underway is by supplying it via a deckwash pump, providing that it is fed from an intake that is below the waterline at all angles of heal and has a minimum flow rate of 10 litres/min, and a maximum output pressure of 3 bar (45 psi).

If using a portable Rainman whilst underway, make sure the system is placed securely and protected from getting wet.

Desalinating While Under Way

The framed Rainman watermaker has been installed and is designed to operate while under way. Ensure that the angle of heel, sea state and boat speed is such that no air bubbles are drawn in to the watermaker. This can damage the membranes.

Desalinating Brackish Water

Brackish water contains some level of salt but is lower salinity than seawater. Examples include estuaries, harbours, and some seas. After heavy rain, some seawater sources can become less saline.

The product water output levels increase when operating in reduced salinity source water. If the product level goes too far above the maximum rated output of the watermaker, the RO membrane may get damaged. For this reason, it is important to pay special attention to the product water flow metre when desalinating brackish water. Do not increase pressure beyond the point where product water flow is more than 110% of the rated output of the system.

Depending on the salinity level of the brackish water, the operating pressure may be as low as 13 bar (200 psi).

Desalinating Brackish Water

Brackish water contains some level of salt but is less salty than seawater. Examples include estuaries, harbours and saline aquifers (bore water). After heavy rain, some sources of seawater can become less saline.

The product water output levels increase when operating in this decreased salinity source water. If the product water output level goes above the maximum rated output, it may damage the membrane. When desalinating brackish water, use the product water flow meter.

To desalinate brackish water, follow the setup and run instructions as described above, however, whilst increasing the pressure, observe the flow meter. If it reaches the rated maximum product water flow for your system, stop increasing the pressure at this point. Note that in instances of very low salinity water, this pressure can be as low as 13 bar (200 psi).

When desalinating brackish water, it is important to monitor the fresh water production rate using the flow meter, so as not to exceed the maximum flow rate for the membranes.

Rated Maximum Outputs
PSU / RO Type	High Output (2 x 40")	Compact (2 x 21")	Economy (1 x 40")
AC Electric	140lph (37gph)	70lph (18gph)	70lph (18gph)
Petrol / Gasoline	140lph (37gph)	70lph (18gph)	70lph (18gph)
12VDC	Not Compatible	Not Compatible	34lph (9gph)

AC Torrent	230lph (60gph)

Exceeding the maximum fresh water production rate may damage the membranes.

Care and Maintenance

Storage

Always store your Rainman watermaker upright in a dry and ventilated area. Dry any obvious moisture off the unit before putting it away. Water can drip from the unit during storage, particularly in hot weather, and it is very important that there is sufficient ventilation to avoid creating an overly humid environment.

Always store the pickle solution mix away from the watermaker.

Seawater and/or pickle solution in an unventilated sealed enclosure in the presence of metals can quickly become a highly corrosive environment, causing anaerobic corrosion to any metal, including marine grade 316 stainless steel.

These photos show severe anaerobic corrosion to a system that was stored in an unventilated locker with pickle solution for just 1 month.

Reverse Osmosis Membrane Care

The Dupont Filmtec membrane or membranes in your Rainman watermaker should last between five and ten years if well cared for. The primary way RO membranes are damaged is through biological growth or ‘fouling’ on the surface of the membranes. This occurs if seawater is left sitting inside the RO pressure vessels for extended periods of time.

In temperate climates, growth can occur in less than two weeks, in tropical climates, growth can occur in as little as a few days. There are no precise times in which fouling can occur, only general guidelines. A conservative approach to membrane care will maximise membrane life.

Regular use of your watermaker is the most effective prevention against fouling. That means using your system at least weekly in temperate climates and every few days in the tropics.

If you are not using your watermaker frequently enough to prevent fouling, then it should be flushed with fresh water or a ‘pickle’ solution.

The following table is a guide to when you might need to flush or pickle:

Rainman Flushing and Pickling Guide
Unused for 2 days or less	No treatment necessary.
Unusued between 2 and 7 days	Fresh water flush.
Unused between 7 and 30 days	Pickle the system.
Unused for 30 days +	Pickle the system, discard the pre-filter and drain the pre-filter housing. Some pre-filters can turn black if stored too long in pickling solution.

When storing the unit for more than a month, discard the pre-filter and drain the pre-filter housing. Some marine deposits can continue to decompose even when immersed in a pickling solution.

Fresh Water Flushing

The Rainman automatic fresh water flush system is an optional unit that automatically flushes your system with fresh water from your boats water tanks every 7 days. Instructions for the Rainman automatic fresh water flush system are in Appendix 3.

To flush your system manually:

After the fresh water tank is full, use the product water direct from the watermaker to fill an open container of water with approximately 10 litres (2.5 gallons) of fresh water.
Open the pressure control valve completely and switch off the unit. Remove the intake hose from the source water and place it in the open container of fresh water. Ensuring the pressure control valve remains open, start the unit and run the entire contents through the system. If the watermaker is installed, use the 3 way valve on the intake to draw water from the bucket.
When the bucket is almost empty, switch off your watermaker, leaving the fresh water in the system.

Never allow the bucket to run dry while the pump is running or the system may be damaged.

Never allow water containing chlorine to enter your watermaker. That includes town or tap water, which contains chlorine, or water from a vessel’s tanks, which also may contain chlorine. Chlorine damages RO membranes.

Pickling Your Watermaker

Pickling fills the membrane housings with a preservative that prevents fouling for up to twelve months.

The best preservative is propylene glycol. Since propylene glycol is a liquid, it is impractical and expensive to ship and store useful amounts. The most commonly used preservative is food grade Sodium Meta-Bisulphate (SMBS) mixed from powder. 1 kg of SMBS powder is supplied with your system. This section describes pickling your system. If you wish to use propylene glycol, instructions are included under the next heading, Pickling in cold climes.

To pickle your watermaker, add 3 X 29ml scoops (approx. 3 heaped tablespoons) of SMBS powder to a 10 litre (2.5 gallon) bucket of fresh water, making a 1% solution of SMBS. After opening the pressure control valve completely, switch off the unit, remove the intake hose from the source water and place it in the open container of fresh water. Start the system again, keeping the pressure control valve open and run the entire contents through the system.
When the bucket is almost empty, switch off your watermaker, leaving the pickling fluid in the system. Do not allow the pickling solution bucket to run completely dry while the PSU is running.

When storing the unit for more than a month, discard the pre-filter and drain the pre-filter housing.

Your watermaker is now pickled and can be stored for up to twelve months.

Do not use SMBS solution at greater concentrations than specified above. High concentrations of SMBS can be corrosive and damage your system.

Avoid inhaling SMBS dust or fumes from SMBS solution. Inhalation of SMBS dust or fumes can cause respiratory problems.

Always store SMBS in a sealed container, in a dry, ventilated place. Even small amounts of air-borne moisture in an enclosed space can react with the SMBS and create a corrosive environment.

Pickling In Cold Climes

If there is a chance that your watermaker will be exposed to freezing temperatures, you’ll need to pickle the unit with Propylene Glycol (PG), otherwise known as potable antifreeze. This will prevent damage to the unit through freezing, as well as preventing biological growth.

There are various brands of potable antifreeze available. It is important to note the percentage of PG in the product. Potable antifreeze labelled ‘concentrate’ is usually near to 100% PG, however, some brands are pre- diluted.

For freeze protection to -15°C (+5°F), use a solution of 30% PG / 70% fresh water.

For freeze protection to -40°C (-40°F), use a solution of 50% PG / 50% fresh water.

Note: if your system has already been pickled with SMBS, flush this out with 10 litres (2.5 gallons) of fresh water before pickling with PG. Mixing SMBS and PG can damage your system.

To pickle your watermaker with potable antifreeze, fill a bucket with 10 litres (2.5 gallons) of PG/fresh water solution. With the unit switched off, place the intake hose in the open container of potable antifreeze solution.
Start the unit with the pressure control valve wide open. When the bucket is almost empty, switch off your watermaker, leaving the pickling fluid in the system. Do not allow the pickling solution bucket to run completely dry while the PSU is running.

Your unit is now protected from freezing and from biological growth for up to twelve months.

Recommissioning After Being Pickled

After the system has been pickled, it is important to clear it of the preservative before making water. The following procedure should be executed:

If the system has been pickled for more than one month, install new prefilter.
If the system has been pickled for more than six months, install new impeller.
Set up the system as per normal operation.
Run the system unpressurised for five minutes. All water going out to brine waste.
Pressurise the system as per normal operation, with product water diverted to waste.
Make water for at least five minutes with product water diverted to waste. Even if you use the optional control panel and the product water quality LED shows green, you should still run for five minutes before sending the product water to your tank.
Test / taste water quality. Pickle solution is distasteful, but not harmful when simply tasted on the tongue.
When water quality is good, send product water into the tank for use.

Changing The Prefilter

Pre-filters should be changed when they become visibly fouled.

To change the pre-filter, place the Pressure Supply Unit (PSU) on the deck of your vessel. Use the supplied filter wrench to remove the clear filter housing.
Replace the cartridge.
Fill the housing with water before screwing it back on. This will aid the priming of the pump.

The correct type of cartridge is a ‘sediment’ or ‘particle’ type cartridge with a 5 micron rating. Do not use a carbon cartridge. Some carbon cartridges also function as sediment filters, and therefore may be labelled as ‘sediment’ cartridges and have a 5 micron rating. These are NOT suitable for use with your Rainman watermaker as they will restrict flow rates and cause problems with your high pressure pump.

High Pressure Pump Maintenance

We recommend you change the pump’s crankcase oil annually. It is important to check the oil level from time to time, particularly if you have had oil leak or spill from the pump at any time.

The correct oil to use is SAE 30 oil. Any grade that ends in 30 is suitable i.e. 5W-30, 10W-30 and 15W-30 are all suitable. These are the most common grades of automotive engine oil. The equivalent ISO oil grade is ISO100.

Crankcase oil can be drained by removing the stainless hexagonal plug on the underside of the high-pressure pump.

To refill the crankcase oil, remove the high pressure pump access panel by undoing 2 screws and then remove the breather plug on the top of the high-pressure pump. Using a funnel as shown, add 330ml (11.2 ounces) of oil.

Oil levels can be checked through the hole in the end of the case. The oil level should be visible in the clear window.

Lift Pump Service

The impeller in the brass lift pump is a consumable item. We recommend inspecting the impeller for signs of wear or cracking every 12 months or 500 hours and replacing if appropriate. The photo on the right shows a heavily worn impeller.

As a matter of preventative maintenance, replace the impeller every year or 500 hours.

The lift pump impeller can be accessed through the triangular port after removing the pre-filter bowl.

Using a 7mm socket, remove the 3 bolts and the triangular plate.

The impeller can then be removed with needle-nose pliers.
Replace impeller with needle-nose pliers using a rotating motion to bend the fins and align the cross-screw with the slot in the shaft.

Service

If your watermaker exhibits any of the following problems, stop the unit immediately and consult your Rainman dealer:

Unusual noises or vibration.
The system pressure will not reach 55 bar (800 psi).
With the unit running, there is no water flow through the green brine output water hose.
The white product hose continues to make salty tasting water after several minutes at 55 bar (800 psi).
Major leaks of water in the PSU or the RO unit.

Alternatively, you can contact Rainman directly for support at www.rainmandesal.com/support-request

Warranty

Rainman watermakers are guaranteed to be free of manufacturer defects and to perform within the published specifications for a period of two years from the date of shipment to the original purchaser.

In the event of a warranty claim, Rainman Technology will inspect the defective component and repair or replace at our discretion. All shipping charges are the responsibility of the purchaser to and from our office in Sydney, Australia.

The warranty is void if the system was mishandled, abused, or not operated / maintained as directed by the user manual. Consumable items, such as pre-filter cartridges, lift pump impeller, high-pressure pump oil, high-pressure pump packings, high pressure hose, engine lubricant, or RO membranes are not covered under the terms of this warranty.

Rainman Technology’s liability under this warranty is limited to repair or replacement of our systems to the original purchaser. Under no circumstances is Rainman Technology liable for consequential damages related to the failure of the system to perform.

Troubleshooting

For troubleshooting the operation of your Rainman, we have a dedicated page in the support section of our website.

Rainman Troubleshooting Guide