Water maker

[crisjones]

Our watermaker water is at least as good as bottled water and usually much better than most shore supplies in the Med. Our guests always say how pure and fresh it tastes. Our ppm tester shows around 150ppm for our watermaker, 200-400 is normal for shore supplies and in some Greek Islands it can be much worse.
Our water goes straight into our main tanks and our galley tap has a carbon block filter on it and this is the tap we use for drinking and cooking water. We have been drinking mainly watermaker water for the last 8 summers and have never had any problems, nor have we ever bought bottled water for the boat.
There are some reports that suggest watermaker water may be lacking in some minerals that you would normally get in shore or bottled water and this may cause problems if you drink exclusively watermaker water over long periods of time. Personally I think if you have a good balanced diet along with a few beers and wines then I doubt you will have any problems at all. Watermaker water is also free from added fluoride that has been linked to some serious health issues as well as the promoted benefit to teeth and gums.

We also have a system for collecting rain water, this is passed through a carbon filter and a 5 micron filter before it goes into our tanks, again we have had no ill effects. Rain water is usually around 50-100ppm so is generally very pure. We would not collect rainwater that is full of red Sahara dust that is pretty common in the Med when winds are from the South.

 

[sailaboutvic]

An carbon filter is a job on our winter list .
One thing Chris nor I have mentioned is the cat pump are noisy .
Although as our it fitted in the fore cabin, shutting. The door cuts the noisy down a lot .
Some thing to take in consideration .

 

[crisjones]

Quite right about the pumps being quite noisy. If you fit the pump onto the main engine then this is not likely to be much of a problem since the engine bay is likely to be well soundproofed.
If using a 240V motor to drive the pump then it will be noisy and it is best not to try and soundproof it in this case since you will want as much airflow as possible to make sure the motor is properly cooled.
If you have 2 membranes then you probably only need to run it for about 30mins per day on average so the noise can be "managed" so as to minimise any problems.
Regarding the filters, I use the industry standard 10" filters and housings for all water filters on the boat. The housings can be bought for around £15-20 each, filter elements are £2-4 for the standard filters and £6-8 for the carbon elements. Much cheaper than any of the proprietary "marine" filter systems and probably just as effective.

 

[catmandoo]

when I was a lad about 60 years ago I did my practical training as an engineer in a company called Weirs and a t one point worked in the test and experimental shop . In those days steam ships were being replaced by diesel and using the synergy of distillation design they developed flash distillation using a vacuum and the heat from the diesel engine cooling water which if I remember was at 95 deg F but was sufficient to boil seawater by doing it at an almost pure vacuum . At the top of the copper pressure vessel was a calandria to collect condensate with a seawater cooled condenser . Small liquid ring pumps extracted the vapour and created the vacuum as well as removing the condensed pure water to storage with concentrated brine being pumped to the sea . The pressure vessel / condenser was about 6feet in diameter and 15 feet high and made of copper alloy / Admiraly Brass and was fitted into large ships for drinking water etc .. It still needied to be sterilised for drinking though I never however saw smaller ones and have since wondered whether a scaled down version might have been be practical for large yachts . On the other hand against membranes they perhaps wer enot cost effective in the smaller duties

 

[geem]

The pressure needle valve was an 1/2 SS brought off eBay .

you can buy a kit from cat to fit their pump and will connection , motor to the pump .

The motor we use is a 1.5 hp 230 50 hz single phases 2 pole motor we run that off our generator.
It uses around 11 amps at 230vac
The motor need to run around 1600 RPM although cat spec say around 1700RPM

But as I said I do know someone who uses a pressure wash pump off an inverter but you would need a big batteries bank plus you may have to keep a spare pump in stock for when the old one packs up ,
Might be able to give more info on this over the winter , has I plain to give it a go .

The fitting determine the size of HP pipe you can use
pump fitting I think are are 3/8 so the pipe you would use would be one that fit that fitting I think the OD of our is about 12 mm

Hope that helps a bit

Hi Vic. As you know we have a similar set up. We did talk during your build. Our Cat pump is the 247. We run it directly from a 1.5kw motor but ours runs at 1480rpm. We run two 40" membranes and a 21" membrane. We make circa 200 litres per hour for the same power draw. We run at 220v and 9 amps so the lower motor speed is using a little less power by the looks of it. Worth adding those extra membranes if you have space and cash. A lot less generator run time. We often just run for 1/2 an hour and make 100 litres and that's good for a couple of days.
One useful addition to the watermaker output to the tank is to buy a uv filter. They sell them for aquariums for about £50 off EBay. They come with a transformer to run at 220v or you can simply ditch the transformer and run the lamp at 12v. UV filtration works very well with RO. Nice to know the water going into the tank has been zapped to kill off any bugs. Lamps last about 6000 hours so it's good value and very easy to install in the tank supply line.

 

[crisjones]

Geem & Vic,

Electric motor speed for single phase 240V standard electric motors is dependent on mains supply frequency and number of poles in the motor. In the UK (and Europe) a 2 pole motor will run at 3000rpm and a 4 pole motor will run at 1500rpm because of the 50hz frequency of the mains electric. The same 4 pole motor will run at 1800rpm in the USA on their 60hz mains frequency. Obviously these are no load theoretical figures so Geem's 1480rpm is pretty close to what you will actually get after allowing for friction, slippage and other losses - in the USA you would expect to get 1750rpm and this is the figure Cat use for calculating standard pump output.
I am sure Vic's motor will be running at 1480rpm, the same as mine and Geem's - unless Vic has his generator outputting 55Hz frequency!!

Our power consumption is around 230V 8.5A at 800psi so very similar to Geem's figures.

The only way to get different motor speeds is to use Variable Speed Inverter drives that allow you to vary the speed of the motor irrespective of supply frequency - certainly not required for a watermaker, the output of the Cat pump at 1480rpm is more than enough for 200 lph product water as Geem says. In the US you could get near 240 lph for the same system - you would need around 20% more power though - you don't get anything for free!!

The UV iradiation is certainly belt and braces and not expensive at around £50, we have not got UV fitted and have never had any problems drinking the water so it is probably not an essential part of the system. Nice to have if you are sensitive to bugs etc.

 

[geem]

Geem & Vic,

Electric motor speed for single phase 240V standard electric motors is dependent on mains supply frequency and number of poles in the motor. In the UK (and Europe) a 2 pole motor will run at 3000rpm and a 4 pole motor will run at 1500rpm because of the 50hz frequency of the mains electric. The same 4 pole motor will run at 1800rpm in the USA on their 60hz mains frequency. Obviously these are no load theoretical figures so Geem's 1480rpm is pretty close to what you will actually get after allowing for friction, slippage and other losses - in the USA you would expect to get 1750rpm and this is the figure Cat use for calculating standard pump output.
I am sure Vic's motor will be running at 1480rpm, the same as mine and Geem's - unless Vic has his generator outputting 55Hz frequency!!

Our power consumption is around 230V 8.5A at 800psi so very similar to Geem's figures.

The only way to get different motor speeds is to use Variable Speed Inverter drives that allow you to vary the speed of the motor irrespective of supply frequency - certainly not required for a watermaker, the output of the Cat pump at 1480rpm is more than enough for 200 lph product water as Geem says. In the US you could get near 240 lph for the same system - you would need around 20% more power though - you don't get anything for free!!

The UV iradiation is certainly belt and braces and not expensive at around £50, we have not got UV fitted and have never had any problems drinking the water so it is probably not an essential part of the system. Nice to have if you are sensitive to bugs etc.

My pal runs the same motor and pumps as me but has three 40" membranes. He gets circa 250 litres/hour for the same current draw as me. It's probably the ultimate set up for the cat pump to squeeze the most water from your diesel if you are using a generator.
With regard to the UV filtration in many ways it's just belt and braces. Here in Santa Marta in Colombia the water is not potable. We are making water in the marina and the seawater is not particularly clean. I feel confident to make water here knowing I am killing any bugs that might get past my membranes. Never had a problem prior to the UV filter but at £50 investment it's seems like money worth spending. UV works particularly well with RO as the low tdc in RO water leaves very little for bugs to hide behind when being zapped with UV light. It's very effective. Hope this helps

 

[sailaboutvic]

Geem & Vic,

Electric motor speed for single phase 240V standard electric motors is dependent on mains supply frequency and number of poles in the motor. In the UK (and Europe) a 2 pole motor will run at 3000rpm and a 4 pole motor will run at 1500rpm because of the 50hz frequency of the mains electric. The same 4 pole motor will run at 1800rpm in the USA on their 60hz mains frequency. Obviously these are no load theoretical figures so Geem's 1480rpm is pretty close to what you will actually get after allowing for friction, slippage and other losses - in the USA you would expect to get 1750rpm and this is the figure Cat use for calculating standard pump output.
I am sure Vic's motor will be running at 1480rpm, the same as mine and Geem's - unless Vic has his generator outputting 55Hz frequency!!

Our power consumption is around 230V 8.5A at 800psi so very similar to Geem's figures.

The only way to get different motor speeds is to use Variable Speed Inverter drives that allow you to vary the speed of the motor irrespective of supply frequency - certainly not required for a watermaker, the output of the Cat pump at 1480rpm is more than enough for 200 lph product water as Geem says. In the US you could get near 240 lph for the same system - you would need around 20% more power though - you don't get anything for free!!

The UV iradiation is certainly belt and braces and not expensive at around £50, we have not got UV fitted and have never had any problems drinking the water so it is probably not an essential part of the system. Nice to have if you are sensitive to bugs etc.

Chris thanks for correct my earlier posting , my motor is a four pole and the label say . 1355rpm . 230v
Although my amps are a lot higher then yours , my Generator panel which is not that old by the way is showning 11amps .
Don't ask me why , I got no idea maybe you can answer it .
I did wonder if the wiring on the 240 side wasn't big enough when the boat was first wired up although not sure if that makes much different on a 240ac side .
Plus I also got mine wired to a plug and not directly to the Gen fuse box , yes I know I should and it's another job I need to do when there time ,
We don't have a flow meter so I measure mine very curdly, by filling a few 1.5 lts bottles up and timing them .
and we can fill just under a bottle in a min .
That's a good 80LPH .
What's be interesting to know is how offen to you change you pre filters ,also you too GEEM , I know the timing can be very wild but we found last year we didn't have to change them at all ,
in Malta in the begin of this year we had to change then twice within a month ,
now that could be because of the filter we brought of eBay , since then we brought a good quality filter costing twice the price and so far no problem but someone we both know Chris said he he changes them every three months or he loses flow .

 

[crisjones]

Chris thanks for correct my earlier posting , my motor is a four pole and the label say . 1355rpm . 230v
Although my amps are a lot higher then yours , my Generator panel which is not that old by the way is showning 11amps .
Don't ask me why , I got no idea maybe you can answer it .
I did wonder if the wiring on the 240 side wasn't big enough when the boat was first wired up although not sure if that makes much different on a 240ac side .
Plus I also got mine wired to a plug and not directly to the Gen fuse box , yes I know I should and it's another job I need to do when there time ,
We don't have a flow meter so I measure mine very curdly, by filling a few 1.5 lts bottles up and timing them .
and we can fill just under a bottle in a min .
That's a good 80LPH .
What's be interesting to know is how offen to you change you pre filters ,also you too GEEM , I know the timing can be very wild but we found last year we didn't have to change them at all ,
in Malta in the begin of this year we had to change then twice within a month ,
now that could be because of the filter we brought of eBay , since then we brought a good quality filter costing twice the price and so far no problem but someone we both know Chris said he he changes them every three months or he loses flow .

No idea why your unit uses 11A and others us around 9A - maybe the pressure settings are higher on yours so need a bit more power?
We change the pre-filters once a year (actually every 6 months of operation since the unit is not used in winter). I have a pressure gauge to measure low pressure side of the Cat pump (inlet port) and this will indicate blocked pre-filters if this pressure reduces noticeably. So far this pressure is normally around 12psi and it may get down to around 10psi after a full summer of operation so I reckon our pre-filters are good for at least that length of time. Obviously we avoid using the watermaker in dirty or contaminated water, Geem may change filters more often if he is forced to operate in less clean water.

 

[geem]

No idea why your unit uses 11A and others us around 9A - maybe the pressure settings are higher on yours so need a bit more power?
We change the pre-filters once a year (actually every 6 months of operation since the unit is not used in winter). I have a pressure gauge to measure low pressure side of the Cat pump (inlet port) and this will indicate blocked pre-filters if this pressure reduces noticeably. So far this pressure is normally around 12psi and it may get down to around 10psi after a full summer of operation so I reckon our pre-filters are good for at least that length of time. Obviously we avoid using the watermaker in dirty or contaminated water, Geem may change filters more often if he is forced to operate in less clean water.

Chris, we have a 50micron and a 5 micron prefilter. If we are making water every other day we leave the filters in. How often we drop them out to clean depends on where we are. The worst place for filters recently was Puerto Velero. Water full of sediment. Two hours running and the filters were blocked. Normally we can run filters for several weeks. We just use clear filter housings so when the filters look discoloured we drop them out to clean. If we are due to do a long passage we remove the filters and flush product water through everything so RO water is on the membranes rather than seawater. This is because our watermaker is in the engine room and everything gets warm from the engine. Any seawater left in the system starts to decompose so you get a nasty smell and high TDS when we first run the system again. The water tank has a 1micron prefilter and a carbon filter on the discharge so we back flush straight from the main tank.
With regard to to dirty filters, we suspend the filters on a string over the side of the boat for a day or so. Bouncing around on a string dislodges the sediment. We then flush them with fresh water and dry them. Usually we get several reuses of the filters from this treatment. We use pleated filters for the 50 micron and block filters for the 5micron. In theory we should all be using pleated filters as they are low pressure drop even when fouled. The block type filters do go high pressure quickly but if you are using gauges across the filters to check pressure you will be ok. The consequences of high negative pressure on the prefilter is reduced life on seals, etc on the HP pump so it is important to watch the condition of our those prefilter.

 

[Firefly47]

Hi All,
All the above threads are really useful and very close to punching all the components for my new DIY watermaker. A couple of questions that I am struggling with and I am sure someone on this website can assist with really quickly - I have purchased the HP pump which is a CAT 277 and has the correct ratings etc to produce the 800PSI. The question is what size electric single phase motor do I need to run this - would I get away with a 1.5HP with a good high torque rating? I am going to be running this set up from a 4KVA generator and presume it will cope with initial load? Also give the Pump is rated at 1750 RPM do I need an electric motor limited to say 1500RPM or is that irrelevant and can the CAT pump cope with higher RPM when not underload thanks if someone can help

 

[sailaboutvic]

1.5HP motor will be fine but do note my 1.5HP motor went running a 277 cat pump will use 10Amps

 

[crisjones]

Hi All,
All the above threads are really useful and very close to punching all the components for my new DIY watermaker. A couple of questions that I am struggling with and I am sure someone on this website can assist with really quickly - I have purchased the HP pump which is a CAT 277 and has the correct ratings etc to produce the 800PSI. The question is what size electric single phase motor do I need to run this - would I get away with a 1.5HP with a good high torque rating? I am going to be running this set up from a 4KVA generator and presume it will cope with initial load? Also give the Pump is rated at 1750 RPM do I need an electric motor limited to say 1500RPM or is that irrelevant and can the CAT pump cope with higher RPM when not underload thanks if someone can help

As Vic says a 1.5hp motor is fine. You do not need anything special - I have run our CAT 277 pump with this 1.5hp Single Phase 4-Pole Motor - Machine Mart - Machine Mart for over 7 years now and it is still working perfectly. The only thing to be careful about is that your power supply is able to provide the necessary start up current. Most suitcase generators will not have sufficient power overhead to deal with the start up current. I use ours via a 3.5kW Victron Inverter and that works great.

 

[Goldie]

Excellent post Vic, many thanks indeed. One question please (Vic or anyone?) regarding the LP pump. How do you size/spec it? I have an engine driven system with Cat HP pump and Stuart Turner 12v DC LP Pump which is no longer made or supported. The system was originally by Aquafresh in Plymouth and they no longer have any interest in watermakers. If/when I need to replace that pump, what do I need to look for? Thanks in anticipation.

 

[crisjones]

Our system has a Jabsco Water Puppy 12V impeller pump as the low pressure supply pump, works great and has only needed one new impeller in 7 years of full time liveaboard usage.

 

[Goldie]

Our system has a Jabsco Water Puppy 12V impeller pump as the low pressure supply pump, works great and has only needed one new impeller in 7 years of full time liveaboard usage.

That’s really useful, thanks. Is flow rate or pressure critical? Our system is producing about 80 lph through 3 membranes.

 

[crisjones]

That’s really useful, thanks. Is flow rate or pressure critical? Our system is producing about 80 lph through 3 membranes.

Our system has 2 x 40" membranes and produces about 160 lph and the Jabsco Puppy is more than adequate for our system so bound to be OK for your smaller system.

 

[Goldie]

Our system has 2 x 40" membranes and produces about 160 lph and the Jabsco Puppy is more than adequate for our system so bound to be OK for your smaller system.

That’s great, many thanks indeed. As is probably apparent, I’m no expert on watermakers!

 

[sailaboutvic]

I have the same pump has Chris , we have one membrane and get around 90lph .
Very happy with our system, three years old now , I just wish I made it years earlier

 

[sailaboutvic]

I have the same pump has Chris , we have one 40' membrane and get around 80/90LPH .
Very happy with our system, three years old now , I just wish I made it years earlier