Watermaker: High pressure pump selection

[SFH]

Putting together my layout and parts list for my watermaker project this winter.

Have decided to go with a DANFOSS APP 0.8 high pressure pump due to lower noise and more energy efficient, but only problem is that the inlet pressure must be min. 0.9 bar (13 psi) and max. 5 bar (72.5 psi) abs. At lower pressures the pump will cavitate, resulting in damage to the pump.

1. Anybody having experience with this pump as HP pump?

I want to keep things as simple as possible but to avoid starving the high pressure pump I am considering including a Pressostat to cut the power to the high pressure pump if the inlet pressure drops below 0.9bar.

I intend to use a Jabsco23690-4003 Junior Puppy self priming pump as boost pump which according to specs "Can generate pressures up to 2 bar (30psi)". SHould be ok but I would actually like to have a higher safety margin.

2. Any advice on boost pump to use instead?


//Steen

[Tellie]

Originally Posted by SFH

Putting together my layout and parts list for my watermaker project this winter.

Have decided to go with a DANFOSS APP 0.8 high pressure pump due to lower noise and more energy efficient, but only problem is that the inlet pressure must be min. 0.9 bar (13 psi) and max. 5 bar (72.5 psi) abs. At lower pressures the pump will cavitate, resulting in damage to the pump.

1. Anybody having experience with this pump as HP pump?

I want to keep things as simple as possible but to avoid starving the high pressure pump I am considering including a Pressostat to cut the power to the high pressure pump if the inlet pressure drops below 0.9bar.

I intend to use a Jabsco23690-4003 Junior Puppy self priming pump as boost pump which according to specs "Can generate pressures up to 2 bar (30psi)". SHould be ok but I would actually like to have a higher safety margin.

2. Any advice on boost pump to use instead?


//Steen

If you're going to use a Danfoss you'll need to pay extra attention to the pre-filtration. Filtering down to 1 Micron is important.

[billknny]

Originally Posted by SFH

I intend to use a Jabsco23690-4003 Junior Puppy self priming pump as boost pump which according to specs "Can generate pressures up to 2 bar (30psi)". SHould be ok but I would actually like to have a higher safety margin.
//Steen

The Junior Puppy would be a very bad choice of feed pumps to use. Your feed pump must NOT be a positive displacement pump.

If at all possible, your plumbing should be set up so the feed pump is below water level and does not need to be self priming. If that is a requirement for some reason, you have a more complex problem....

A March magnetically coupled centrifugal pump matched to the overall flow rate of the system is far better choice than the Junior Puppy.

[atoll]

Originally Posted by SFH

Putting together my layout and parts list for my watermaker project this winter.

Have decided to go with a DANFOSS APP 0.8 high pressure pump due to lower noise and more energy efficient, but only problem is that the inlet pressure must be min. 0.9 bar (13 psi) and max. 5 bar (72.5 psi) abs. At lower pressures the pump will cavitate, resulting in damage to the pump.

1. Anybody having experience with this pump as HP pump?

I want to keep things as simple as possible but to avoid starving the high pressure pump I am considering including a Pressostat to cut the power to the high pressure pump if the inlet pressure drops below 0.9bar.

I intend to use a Jabsco23690-4003 Junior Puppy self priming pump as boost pump which according to specs "Can generate pressures up to 2 bar (30psi)". SHould be ok but I would actually like to have a higher safety margin.

2. Any advice on boost pump to use instead?


//Steen

you would need to have a higher flow rate from the pump than demand to the high pressure pump to maintain 1-2 bar of pressure which might be problematic with this type of continuous running impellor pump without some sort of pressure regulator

[mvmojo]

If you have air conditioning, you may be able to use the existing pump. That's what I do. The water puppy would not be appropriate as a boost pump. You want a centrifugal pump mounted below the waterline so it is continuously flooded. You may also want to put a vent line in the inlet to avoid an air lock.

[Valmika]

I don't mean to sidetrack the thread but I did see some guy in Florida selling a watermaker kit for about $1400. It appears he is using a Karcher pressure washer pump for his high pressure pump. I'm not sure if this is a good idea or not? Are real watermaker pumps made differently for salt water? Anybody care to blow this thing full of holes?

https://www.youtube.com/watch?v=6SYHVs-uZE0

[daletournier]

Originally Posted by Valmika

I don't mean to sidetrack the thread but I did see some guy in Florida selling a watermaker kit for about $1400. It appears he is using a Karcher pressure washer pump for his high pressure pump. I'm not sure if this is a good idea or not? Are real watermaker pumps made differently for salt water? Anybody care to blow this thing full of holes?

From what ive read here its not a good idea BUT theres a cat next to me using one, he built it himself, it puts out 140l/hr and has been going strong for a couple of years. Will it keep going? I dont know.

[Franziska]

Dale, is that neighbor of yours using the complete setup from the video or is he using a complete homegrown one with a Kärcher as HP pump?
If he really got several years out of the Kärcher pumping saltwater, that sounds remarkable to me.
Any chance you could verify the latter with him?
Thanks.

[tarian]

Water maker

try this post over here in the uk
the guy uses a cat 277 pump

[Quadrille in JB]

Originally Posted by Valmika

I don't mean to sidetrack the thread but I did see some guy in Florida selling a watermaker kit for about $1400. It appears he is using a Karcher pressure washer pump for his high pressure pump. I'm not sure if this is a good idea or not? Are real watermaker pumps made differently for salt water? Anybody care to blow this thing full of holes?

I’ve been using this seaeaterpro setup for the past year with great results. His theory is that all parts are available off the shelf. In June when we were in Norway and I went into a hardware store and saw the pressure washer for ~$200 US. Unlike other pressure washer pumps this one is made of a composite material, not pot metal like most cheap pumps.
I’ve had great customer support and the mfg claims he has had only 1 pump failure out of 200+ units in over 2 years. I routinely get 20+ gph out of the system with ~300 ppm dissolved solids Calibrated for NaCl.
The system comes with all fittings and lines to install it, even a roll of T-tape.

I am not connected to this company other than being a satisfied customer.

[a64pilot]

You may want to consider one of these pumps
http://www.cruiserowaterandpower.com...aker_Parts.php

[daletournier]

Originally Posted by Franziska

Dale, is that neighbor of yours using the complete setup from the video or is he using a complete homegrown one with a Kärcher as HP pump?
If he really got several years out of the Kärcher pumping saltwater, that sounds remarkable to me.
Any chance you could verify the latter with him?
Thanks.

Hi, I just went and talked to Peter, he's been using it once a week for 18 mths as a full-time liveaboard. He told me he purchased the one with the aluminium pump, I think he said K4?

I haven't watched the utube so I can't say if it's the same. I've seen his setup, he has the same membrane setup as me (rainman) and has the Karcher as a complete unit in its plastic housing mounted next to them.

As I said, I have no idea how long it will last, all I know is he's using it, it works and it's been going for approximately 18 mths.

[daletournier]

Originally Posted by daletournier

Hi, I just went and talked to Peter, he's been using it once a week for 18 mths as a full-time liveaboard. He told me he purchased the one with the aluminium pump, I think he said K4?

I haven't watched the utube so I can't say if it's the same. I've seen his setup, he has the same membrane setup as me (rainman) and has the Karcher as a complete unit in its plastic housing mounted next to them.

As I said, I have no idea how long it will last, all I know is he's using it, it works and it's been going for approximately 18 mths.

Correction, he's using the 5.2 Karscher.

[Franziska]

Awesome answer.
Thanks for checking this.I wrote to Kärcher a while ago to get their view on pumping saltwater but never got a reply...

[a64pilot]

Originally Posted by Franziska

Awesome answer.
Thanks for checking this.I wrote to Kärcher a while ago to get their view on pumping saltwater but never got a reply...

Assuming you fresh water flush the pump after every use, it will make it last much longer.
I do not think pumping salt water is as bad as allowing salt water to sit in it continuously.
However as inexpensive as they are, carry a spare