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Old 12-03-2010, 17:13   #1
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How Much Water to Flush a Ventura 150 ?

Anyone know how much product water it takes to backflush a Spectra Ventura 150 when fitted with an MPC500 controller ?

At 6.5 gallons per hour, I figure I could be using most of the first hour's output just for the flush.

Just trying to do some calc to see if I really could get away with the 6.5 GPH unit as I like the low Amp draw.

Duncan
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Old 12-03-2010, 17:23   #2
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The Ventura 150 with the MPC5000 will use one gallon per minute during the fresh water flush cycle. The newer MPC5000 controllers are programed to run three minutes so you will use three gallons of fresh water. If it is an older MPC it is programmed for five minutes and use five gallons. The MPC controllers can be re-set for a three minute flush. This is for the Ventura 150 only.
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Old 13-03-2010, 07:19   #3
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Watermaker flush cycles / fresh water used

Duncan,
I'm sorry to disagre with Tellie.....but.....

1) The fact is this.....
With the standard 3 minute "fresh water flush", you should use approx. 4.5 gallons of fresh water......(for the purpose of being away from the boat for a month, I usually allow a "fudge factor", and assume about 5 gals per flush. thereby making sure I have adequate fresh water in the tank(s).....

I've had a Spectra Ventura MPC-5000 installed now for over 3 years, and 12,000+ miles offshore.....and both my experiences and the data supplied by Spectra shows different figures.....

{Have a look at the article and photos of my installation.... Watermaker }

a) The nominal flow rate thru the Ventura is approx. 1.5GPM so 1.5 gallons x 3 minutes = 4.5 gallons.......
This nominal flow rate spec of 1.5GPM / 90GPH is directly from Spectra's website tech information, and with normal product water output of approx 7.5% of the nominal flow (spec'd by Spectra), giving the nominal product output of 6.75GPH (~160 gpd), I think this is accurate.....

b) In my own experiences, with my own Spectra Ventura MPC-5000, I do find approx. 4.5 gallons of fresh water used, for the standard 3 minute flush cycle......

Notwithstanding what some may wish to believe, this is NOT that big of a deal.....it keeps your watermaker working in good order, and is just part of the process of owning/using a good quality watermaker...



2) Please understand that while the normal 3-minute "fresh water flush" may use 4.5 gallons, this is just done every 5 days (typically), when you've not made water in that time peroid.....and the "start-up flush" which it does automatically when you start to make water uses only about 1/2 gallon......
Do NOT confuse the two.....

So, depending on what you're refering to, it's possible that your concern is uneeded????


3) As for whether you can "get away with" with just a 6.5gph unit....
Well, please understand that watermaker choice is a VERY personal and application specific choice!!!!
Do NOT be mislead into believing that you "need" a specific unit, nor specific size unit......
Make your choice based on YOUR needs and application......
See other threads on these specific matters....
http://forum.ssca.org/phpBB3/viewtopic.php?f=4&t=10706


I do hope this helped....

John
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Old 13-03-2010, 07:40   #4
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Watermakers.....

Oh, I forgot to mention one important thing....
In the ~600 hours / 3+ years of use of my Vetura MPC-5000, I find that I consistantly get 7gph output....sometimes as hgh as 7.4gph, but always 6.9gph or higher......

And with their unit adjusting pressure (for water temp variables) this makes for great consistancy that I was NOT aware that I'd have.....
So, it's been a nice surprise....

Good luck...

John
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Old 14-03-2010, 19:46   #5
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I love to be disagreed with LOL. To many variables from one Ventura 150 to the next. Not so much the 150 itself but the huge differences in installations from one boat to the next. A new properly adjusted 150 should not be using 4.5 gallons of fresh water. Of course we are talking a difference of 1.5 gallons of water, a realitivly small amount in reality. Fudge factors as ka4wja suggests is probably good idea in anything boat related. Spectra understands this as well. But again how your 150 is installed and the feed pressure delivered to your 150 from the boats systems is a huge determining factor in the amount of fresh water used in a flush. In the many many 150s I've installed, repaired and serviced the gpm of fresh water used is all over the scale. A properly set up 150 unit will/should be closer to the 3gpm. This is where a self installed unit and one installed or at least commisioned by a trained tech can make a difference. Just a few things learned along the way after working on Spectras.
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Old 14-03-2010, 23:17   #6
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Watermaker flush...

Quote:
Originally Posted by Tellie View Post
I love to be disagreed with LOL.
I'm happy to oblige...


Seriously though, my Ventura MPC-5000 was professionally installed and commissioned by a trained/certified Spectra dealer (who did an outstanding job!), and if I should be using less water for fresh water flushing, then I'd really like to know.....
If my unit is not operating properly / was not properly installed, I'd like to know.....
But, using the info provided by Spectra, shows that all is well.....
Although, the Ventura manual states fresh water flushes will use approx. 2.5 gallons, my dealer stated that is the minimum and that we should assume more than 3 gallons, and my experiences and their tech support show approx. 4 - 4.5 gallons.....



Quote:
Originally Posted by Tellie View Post
To many variables from one Ventura 150 to the next. Not so much the 150 itself but the huge differences in installations from one boat to the next. A new properly adjusted 150 should not be using 4.5 gallons of fresh water.
Yes, I understand that there are many variables (and I'm 200 miles from my boat at the moment), but using the info from Spectra's website, my fudge-factor figures track with those factory figures....

From Spectra's website "tech support" ( Untitled )
Quote:
The pressures shown on the Spectra gauges and panels are the feed pressure not the membrane pressure. And, because sea temperatures vary widely and Spectra Watermaker membrane pressures vary with sea temperature, each model has a Nominal Operating Pressure Range, but system flow should vary only slightly. System flow can be measured by collecting both the brine and the product into a container and timing how long it takes to fill it.

VENTURA 150 55-70 PSI 1.5GPM

200C 70-80 PSI 1.5GPM
My operating feed pump pressures are typically around 55 - 60psi (and about 40 psi during a fresh water flush), and while I DO understand that the "real world" of products installed in boats can vary from the "factory specs", I found it quite telling that Spectra specifically states that even with the variables they mention, that "system flow should vary only slightly"....

Although I've NOT measured the total flow (by feeding brine discharge and product output into a bucket and measuring it), my math says that 1.5gpm x 3minutes = 4.5 gallons......
BUT, since I've not actually measured the flow myself, I could be off by a gallon.....
And, since I wrote "approx" in my earlier post, I feel safe....whew!
And, I usually figure 4 - 5 gallons per flush cycle and haven't run a tank dry during flushes, so I think my calculations are fairly close....



Quote:
Originally Posted by Tellie View Post
Of course we are talking a difference of 1.5 gallons of water, a realitivly small amount in reality. Fudge factors as ka4wja suggests is probably good idea in anything boat related. Spectra understands this as well. But again how your 150 is installed and the feed pressure delivered to your 150 from the boats systems is a huge determining factor in the amount of fresh water used in a flush. In the many many 150s I've installed, repaired and serviced the gpm of fresh water used is all over the scale.
YES, I DO understand that we are taking about a very small amount of water, and that there are many variables, etc. so this point may seem fairly inconsequential, but the difference between 1gpm flow and 1.5gpm flow is a 50% increase, which I would not interpet as "only a slight variation" (as Spectra writes).....
And, perhaps when someone is in the planning / decision stage, it would best to give them the best possible data for their decision making process......so, using the factory figures and my real world experiences is what I posted.....

And, since I do NOT have the experience level that Tellie does, I would normally defer to his hard-won knowledge.....
But, in this case, I'm standing by my original figures.....
Spectra posts the 1.5gpm flow data on their website, and they state
Quote:
system flow should vary only slightly
, so I think my figures, whether they're just a big fudge-factor or actual factory supported results, are accurate.....


Quote:
Originally Posted by Tellie View Post
A properly set up 150 unit will/should be closer to the 3gpm.
I assume this is a typo??? since that would mean a flush would use 9 gallons.....



Quote:
Originally Posted by Tellie View Post
This is where a self installed unit and one installed or at least commisioned by a trained tech can make a difference. Just a few things learned along the way after working on Spectras.
I'm assumming that setting of feed pressures, confirming proper feed water supply (both raw water, and fresh water) and both product and brine output flows are not restricted, etc. among other things is what you're refering to here......but, if there is something specific that you could point me to, I'll be sure to have a look-see when I get back on board in a week....


Tellie, please understand that I do believe your experiences, but the specs from Spectra (and my experiences) are different, and I thought that Duncan needed to know the "maximum" fresh water he'd use in a flush cycle, and since my experience parallels the factory specs, I thought that was the way to go....

Fair winds...
John
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Old 14-03-2010, 23:24   #7
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I recall that Spectra spec'd a gallons per flush figure. I adjusted the time to pump just that amount of water. It's no big deal. The flush water is a small amount of the total used in most cases. Might be an issue if your tank is small.
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Old 15-03-2010, 02:26   #8
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Thanks all, that helps.

2) Please understand that while the normal 3-minute "fresh water flush" may use 4.5 gallons, this is just done every 5 days (typically), when you've not made water in that time peroid.....and the "start-up flush" which it does automatically when you start to make water uses only about 1/2 gallon......
Do NOT confuse the two.....


I didn't properly understand this, thanks John. I feel more comforable now I know that I'm not going to be constantly losing 1/2 hr+ (4Ah ?) of running time if I'm using the unit every couple of days.

Duncan
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Old 15-03-2010, 04:09   #9
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QUOTE=ka4wja;419046]I'm happy to oblige...


Seriously though, my Ventura MPC-5000 was professionally installed and commissioned by a trained/certified Spectra dealer (who did an outstanding job!), and if I should be using less water for fresh water flushing, then I'd really like to know.....
If my unit is not operating properly / was not properly installed, I'd like to know.....I wrote my previous comment on the fly so it was a general comment not specific to your unit. I'm sure from what you have describe all is well with your unit and nothing you previously stated would or has me concerned at all that there is anything amiss with your unit.
But, using the info provided by Spectra, shows that all is well.....
Although, the Ventura manual states fresh water flushes will use approx. 2.5 gallons, my dealer stated that is the minimum and that we should assume more than 3 gallons, and my experiences and their tech support show approx. 4 - 4.5 gallons.....
I would agree with your dealer since he was the one that installed and set up your unit.



Yes, I understand that there are many variables (and I'm 200 miles from my boat at the moment), but using the info from Spectra's website, my fudge-factor figures track with those factory figures....Are you taking your units figures directly from the MPC control panel display or from measured and timed results. Reason is that the MPC is calibrated from the product flow, measured and timed.


From Spectra's website "tech support" ( Untitled )

My operating feed pump pressures are typically around 55 - 60psi (and about 40 psi during a fresh water flush), and while I DO understand that the "real world" of products installed in boats can vary from the "factory specs", I found it quite telling that Spectra specifically states that even with the variables they mention, that "system flow should vary only slightly"....

Although I've NOT measured the total flow (by feeding brine discharge and product output into a bucket and measuring it), my math says that 1.5gpm x 3minutes = 4.5 gallons......
BUT, since I've not actually measured the flow myself, I could be off by a gallon.....
And, since I wrote "approx" in my earlier post, I feel safe....whew!
And, I usually figure 4 - 5 gallons per flush cycle and haven't run a tank dry during flushes, so I think my calculations are fairly close....I bet your calculations are probably pretty close and you are "safe" But as you stated "I've NOT measured the total flow (by feeding brine discharge and product output into a bucket and measuring it)" This is actually a very important step that you should do every six months to a year. Your unit uses a roto flow meter that measures product water only. It is calibrated at the factory and is usualy pretty acurate right out of the box. But remember these figures are set under factory conditions under ideal conditions. One kewl thing Spectra does that others don't is that they send out a "SYSTEM PERFORMANCE TEST REPORT" They actually test each unit before it leaves the factory. All the measurements are then calibrated and the results are written down and sent along with the unit. You might still have that sheet in your manual. It's a good idea to occasionally compare those results especially after three years.




YES, I DO understand that we are taking about a very small amount of water, and that there are many variables, etc. so this point may seem fairly inconsequential, but the difference between 1gpm flow and 1.5gpm flow is a 50% increase, which I would not interpet as "only a slight variation" (as Spectra writes).....
And, perhaps when someone is in the planning / decision stage, it would best to give them the best possible data for their decision making process......so, using the factory figures and my real world experiences is what I posted..... I agree completly. Real world data coming from real users is very important.

And, since I do NOT have the experience level that Tellie does, I would normally defer to his hard-won knowledge.....
But, in this case, I'm standing by my original figures.....
Spectra posts the 1.5gpm flow data on their website, and they state , so I think my figures, whether they're just a big fudge-factor or actual factory supported results, are accurate.....Again I bet your results are pretty accurate as well. But you know if you ever get around to my part of the world I'm coming over to your boat and I'm gonna throw some of that hard-won knowledge at you and test your system and re-calibrate it with the newest software an latest data and info. It'll cost ya a beer though.

I assume this is a typo??? since that would mean a flush would use 9 gallons.....Yeah a typo, too quick to write and not proof read.




I'm assumming that setting of feed pressures, confirming proper feed water supply (both raw water, and fresh water) and both product and brine output flows are not restricted, etc. among other things is what you're refering to here......but, if there is something specific that you could point me to, I'll be sure to have a look-see when I get back on board in a week....


Tellie, please understand that I do believe your experiences, but the specs from Spectra (and my experiences) are different, and I thought that Duncan needed to know the "maximum" fresh water he'd use in a flush cycle, and since my experience parallels the factory specs, I thought that was the way to go....You're right. But one of the great things about Spectra is that they are constantly testing and re-evaluating their systems. They want as much real world information from owners like you as they can get. Many of our solutions to problems come from owners who have questioned in detail their systems using the comparisions found on the website. The fresh water flush is one of those areas that real world experiance has changed the way things are done. Older MPC controls on Ventura 150s where set for a five minute flush duration. Personally, I like little longer flush time using a little more fresh water. That's probably due more to what I'm used to and figure that for such an expensive piece of equipment you can't over flush a unit. Hope this helps clear up my take on the issue a bit. Tellie

Fair winds...
John[/QUOTE]
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Old 15-03-2010, 04:32   #10
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Quote:
Originally Posted by duncan_ellison View Post
Thanks all, that helps.

2) Please understand that while the normal 3-minute "fresh water flush" may use 4.5 gallons, this is just done every 5 days (typically), when you've not made water in that time peroid.....and the "start-up flush" which it does automatically when you start to make water uses only about 1/2 gallon......
Do NOT confuse the two.....

I didn't properly understand this, thanks John. I feel more comforable now I know that I'm not going to be constantly losing 1/2 hr+ (4Ah ?) of running time if I'm using the unit every couple of days.

Duncan
Actually you will lose that each time you make water plus the 1/2 gallon John qoutes. The MPC5000 will "AUTO FLUSH" itself each time after you use the watermaker. But 3-5 amps every couple of days, about 1-2 amps a day, is realitively a very small amount of power. If you're cutting your amp budget that close I'd be interested in finding out more about your electrical system before deciding on which watermaker is right for you. There's a balance between your boats electrical needs and capabilities. This is just one of many reasons why I stress many times that choosing the right watermaker to fit that balance is more important than looking at "What's the cheapest watermaker I can buy, or build?". Cheap up front can get real expensive quick.
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Old 15-03-2010, 10:09   #11
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Watermaker stuff....

Wow, I really need to try to be brief, since I drifted this upstream quite a bit...
Sorry if I seemed "contrary".....not my intention....I think we're in pretty close agreement....
And, as Tellie wrote, it's just a small amount of water.....

{And just FYI, I did have my Spectra dealer on board just a couple months ago.....
He needed to replace a faulty salinty probe (with a new version), and changed / updated software at that time.....(covered under warranty)
While I didn't confirm the total flow at that time, I will do so (and compare to the original installed test sheet) when I get back on board in a week....
Thanks for reminding me!!!}


Quote:
Originally Posted by Tellie View Post
There's a balance between your boats electrical needs and capabilities. This is just one of many reasons why I stress many times that choosing the right watermaker to fit that balance is more important than looking at "What's the cheapest watermaker I can buy, or build?". Cheap up front can get real expensive quick.
Ahmen to that!!!



Quote:
Originally Posted by Tellie View Post
The MPC5000 will "AUTO FLUSH" itself each time after you use the watermaker
Duh, I forgot to mention that.....

Gotta go....

John
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