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Re: Watermaker Dead

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  • edmund_steele
    Gary, I rechecked all of the pins on Plug #1. With the 220 V breaker turned ON and the panel rotary switch turned ON and with the plug connected to the
    Message 1 of 22 , Sep 1, 2007
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      Gary,
      I rechecked all of the pins on Plug #1. With the 220 V breaker
      turned "ON" and the panel rotary switch turned "ON" and with the plug
      connected to the board, I had:

      Pin #4 53V with the meter set on AC and 24 V with the meter set to DC
      (I got the same results testing Fuse F1)

      After a couple of minutes, Pin #5 thru Pin #11 all showed 24V DC –
      did not test when this happened timewise.

      I tested the pins on T1 and T2. with fuses to the "top":
      T1 left pin 21.8V center pin ~ 0 right pin 23.5V
      (should be ~ 12V?)
      T2 left pin 21.6V center pin ~ 0 right pin 5.6V
      (correct voltage)

      I next disconnected the Plug#1 and tested between pin #1 and pin #5.
      It showed 53V with the meter set on AC and 24 V with the meter set to
      DC but only with the rotary switch turned to "ON". With just the 220V
      breaker, there was no voltage here.

      Next I jumpered pin #5 to pin #8 and pin #1 to pin #9. The low
      pressure pump came on and ran normally. I did not have enough jumpers
      to try the high pressure pump as well. We are taking a trip to the
      big city on Sunday and I will try and find some place that looks like
      a Radio Shack. Back on board Friday.

      The relays RY1, RY2 and RY3 are labeled 12V and T1 is labeled "Korea
      406 KA7812" so it looks like the correct part.

      My plan is to build a manual work-around as you suggested and then
      try to figure out the control board issue.

      BTW, the high pressure sensor switch was "open".

      Ed


      --- In amelyachtowners@yahoogroups.com, amelliahona <no_reply@...>
      wrote:
      >
      > Regarding the Hi Pressure Switch:
      >
      > I worte: "(Dessalator told me what it was once but I don't recall
      > now) in order to protect all the plumbing from excessively
      > high pressures."
      >
      > I found my email from Dessalator and it said:
      >
      > Dessalator: " It shuts down the system at 68/70 bars."
      >
      > Gary
      >
    • amelliahona
      Hi Ed: Great work. When looking at these voltages I need to always know what ground source you are referencing. Ed wrote (enclosed in : Pin #4 53V with
      Message 2 of 22 , Sep 3, 2007
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        Hi Ed:

        Great work. When looking at these voltages I need to always know
        what ground source you are referencing.

        Ed wrote (enclosed in " " :

        " Pin #4 53V with the meter set on AC and 24 V with the
        meter set to DC. (I got the same results testing Fuse F1)"

        I can't explain this. Where you using pin 1 as the ground for these
        measurements? In fairness the only source I have for pin 4 being
        220 VAC is from Dessalator (a notoriously unreliable source of
        informatiion on this subject), as I have not measured or traced
        those wires myself. To clear this up, perhaps you would do the
        following and let me know what you find:
        1. unplug plug 1 (P1)
        2. with the 220 VAC breaker set and the 24 VDC panel switch ON
        3. measure the voltage (both DC and AC) between pin 1 and pin 4
        4. and (with power off) trace the red wire from pin 4 to see where
        it goes (I can't make out its origin from the photos I have here.

        "After a couple of minutes, Pin #5 thru Pin #11 all showed 24V DC –
        did not test when this happened timewise. "

        This would be appropriate as this essentiallly provides "activating"
        24 VDC power (and return) to the following:
        1, hi pressure pump relay,
        2, low pressure pump relay, and
        3. bypass solenoid.
        The control side (i.e. sinking pins 7, 9, & 11 to ground) is controlled
        through relays RY1, RY2, & RY3.
        Furthermore this seems to imply that the logic board timer circuit
        and some of the other ICs are functioning properly.

        " I tested the pins on T1 and T2. with fuses to the "top":
        T1 left pin 21.8V center pin ~ 0 right pin 23.5V
        (should be ~ 12V?)"

        Again, please verify what you were using as the ground for your
        multi-meter when making these measurements. The right pin
        should be 12 VDC, the center pin is ground (0 volts DC)), and the
        left pin is the input from the full bridge rectifier/capacitor C1
        combination. It is dependant on the input AC voltage on pin 4
        (hence my need to know that voltage accurately). It may be that
        T1 is shorted ?????, or the rectifier is gone????? and this is the cause
        of your failure(s)?????? That would be a fairly logical failure mode.

        " T2 left pin 21.6V center pin ~ 0 right pin 5.6V
        (correct voltage)"

        This seems correct except I would have expected a 12 VDC voltage
        on the left pin. The approx 5 VDC output voltage is appropriate,
        and is what is fed to all the ICs and is why the green logic board
        LED is appropriately illuminated and your logic board timer is working.

        " I next disconnected the Plug#1 and tested between pin #1 and
        pin #5. It showed 53V with the meter set on AC and 24 V with the
        meter set to DC but only with the rotary switch turned to "ON". With
        just the 220V breaker, there was no voltage here."

        From this I believe that the 53 VAC you are seeing is an erronious
        characteristic of your digital voltmeter when looking at DC voltages
        OR that there is a failure mode that is allowing AC to bleed on to the
        DC circuits.
        To trouble shoot this, I would:
        1. with P1 plugged into the logic board
        2. measure DC voltage between pins 1 and 4, and between pins 1 & 5
        3. do this measurement in each of two configurations, with:
        first: with the 220 VAC breaker set on ONLY, (rotary switch off).
        second: 220 VAC breaker OFF and only the rotary panel switch on.

        "Next I jumpered pin #5 to pin #8 and pin #1 to pin #9. The low
        pressure pump came on and ran normally."

        Great, that is as it should be. Jumpering pin 5 to 8 provides 24 VDC
        to the low pressure pump relay, and jumpering pin 1 to pin 9 provides
        a ground return for the relay, thereby achieving what RY1 does, that
        is activating thelow pressure pump control relay (the 220 VAC control
        relay).

        So the manual work around is to have three single pole single
        throw switchs. One switch each on pins 7, 9, and 11 with one pole
        of each switch to each of those pins and the other pole going to
        ground (i.e. pin 1). You then manually throw switch 1, activating
        the low pressure pump, wait a bit, then throw switch 2, activating
        the high pressure pump, then dial up the pressure until product
        water is made, and finally when your electronic EC meter shows
        you have truely good product water, you throw switch number three,
        diverting the product water to your fresh water tanks. Then, if your
        EC meter alarm sounds due to a failure resulting in the production
        of poor quality water you turn off switch three and proceed to shut
        down the system to make repairs. This is the "logic" that should
        have been part of this board, but was not.

        "406 KA7812" so it looks like the correct part"

        I have confirmed that the output of T1 (aka Motorola 7812 or KA7812)
        should be 12 VDC.

        "BTW, the high pressure sensor switch was "open".

        Thanks Ed. That confirms what I was theorizing.

        "It shuts down the system at 68/70 bars."

        That is between 986 and 1015 psi.

        Regards,

        Gary
      • amelliahona
        Ed: Regarding I tested the pins on T1 and T2. with fuses to the top : T1 left pin 21.8V center pin ~ 0 right pin 23.5V (should be ~ 12V?) I
        Message 3 of 22 , Sep 3, 2007
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          Ed:
          Regarding
          " I tested the pins on T1 and T2. with fuses to the "top":
          T1 left pin 21.8V center pin ~ 0 right pin 23.5V
          (should be ~ 12V?)"

          I just uploaded to the Files section the data sheet for T1
          This voltage regulator is made by many different manufacturers
          and in many different voltage configurations, but this
          data sheet is typical and is the exact one for the motorloa
          chips on my logic board and should be representative for
          your KA7812 chips.

          Gary
        • amelliahona
          STOP THE PRESSES: Ed I deduced some new information related to: I rechecked all of the pins on Plug #1. With the 220 V breaker turned ON and the panel
          Message 4 of 22 , Sep 3, 2007
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            STOP THE PRESSES: Ed I deduced some new information related to:

            " I rechecked all of the pins on Plug #1. With the 220 V breaker
            turned "ON" and the panel rotary switch turned "ON" and with
            the plug connected to the board, I had:

            Pin #4 53V with the meter set on AC and 24 V with the meter set
            to DC (I got the same results testing Fuse F1)"

            Dessalator told me via email over a year ago that pin 4 is 220
            VAC. THIS CAN NOT BE CORRECT. Based on the Spec. Sheet for
            T1 (7812 voltage regulator), the max Vi (input voltage is 35
            Volts DC). This input voltage comes directly input from the
            bridge rectifier/filter capacitor (C1). There is NO WAY FOR
            220 VAC to be rectified and filtered and end up with 35 VDC.
            However, 53 VAC would be rectified and filtered to
            approximately 24-25 Volts AC.

            To answer this questions we need to know: WHAT IS THE
            AC VOLTAGE BETWEEN PLUG 1 PIN 1 AND PIN 4 with the
            breaker on. If it is indeed about 53 Volts AC then
            where does that voltage come from. There must be a small
            transformer somewhere that steps the 220 VAC down to about
            53 VAC. We need to trace the red wire on P1 pin 4 and
            see where it goes. The transformer is not on the logic board.

            The DC input voltage to the 7812 (T1) voltage regulator
            must be at least 2 volts more than the output voltage (per
            the spec sheet) and we know that the output voltage HAS
            TO BE 12 VDC because that is what RY1, RY2, and RY3
            require. So I believe there is definitely a problem with T1.

            The 24 VDC that you read on pin 4 is just your multimeter
            trying to measure AC voltage.

            Lastly, it will be important to see if the 24 Volt DC out of T1
            has burned up the control coils of RY1, RY2, and RY 3. You
            could test them with a 12 VDC source to see if they still
            energize (clicking sound). I'll try and post a photo showing
            the pins to apply 12 volts DC to to test them.

            Ed if you want to take this ongoing trouble shooting off the
            forum please feel free to email me directly at
            AgCEagle at comcast dot net

            Regards, Gary
          • Judy
            Gary and Ed, I have been reading all of your posts with keen interest and am trying to produce a troubleshooting guide with all of the info. I would
            Message 5 of 22 , Sep 4, 2007
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              Gary and Ed,

              I have been reading all of your posts with keen interest and am trying
              to produce a troubleshooting guide with all of the info.

              I would appresciate it if you kept your posts on the Amel forum, or if
              not, copy me at KE5FTK at winlink.org.

              Best,

              Bill Rouse s/v BeBe SM2 #387
              sailing with Captain Judy in Curacao

              --- In amelyachtowners@yahoogroups.com, amelliahona <no_reply@...> wrote:

              > ... Ed if you want to take this ongoing trouble shooting off the
              > forum please feel free to email me directly at
              > AgCEagle at comcast dot net
              >
              > Regards, Gary
              >
            • amelliahona
              Judy: I will keep it on the forum as requested. I just didn t want to bore anybody. I have used your old board to verify some of what I have written. I have
              Message 6 of 22 , Sep 4, 2007
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                Judy: I will keep it on the forum as requested. I just didn't want to
                bore anybody.

                I have used your old board to verify some of what I have written. I
                have not attempted to fix it because I didn't have access to a 220 VAC
                50 Hz power supply for testing, but now that I know that the board
                doesn't take 220 volts, I just need to verify the correct input voltage
                and perhaps I can repair yours. Or at the very least I can bypass the
                power supply part and verify the logic/relays work.

                On another note, I am now on page 8 of a Users Guide, including
                troubleshooting, photos of all components and specifications. I will
                post parts of it in the files section as it is complete. Please note
                any ammendments (notated in the header) when referencing this
                item as it is a work in progress. I have already updated the file
                entitled Logic Board Schematic.pdf to reflect the discoveries of
                yesterday.

                The NAIS JSI-12v relays on the logic board are $1.49 USD each and
                the T1 & T2 voltage regulators (Motorola 7812CT and 7805CT) are
                $0.39 USD each I just ordered ten of each for spares and trouble
                shooting.

                Happy sailing Judy,

                Gary

                "Judy" <sailingjudy@...> wrote:
                >
                > Gary and Ed,
                >
                > I have been reading all of your posts with keen interest and am trying
                > to produce a troubleshooting guide with all of the info.
                >
                > I would appresciate it if you kept your posts on the Amel forum, or if
                > not, copy me at KE5FTK at winlink.org.
                >
                > Best,
                >
                > Bill Rouse s/v BeBe SM2 #387
                > sailing with Captain Judy in Curacao
              • edmund_steele
                Gary, I am back aboard. (Jerusalem was great!) Couple of things. First, all of my voltage measurements were referenced to Pin 1 ground. Second, I noticed that
                Message 7 of 22 , Sep 6, 2007
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                  Gary,
                  I am back aboard. (Jerusalem was great!) Couple of things.

                  First, all of my voltage measurements were referenced to Pin 1 ground.

                  Second, I noticed that my board does not have the C1 capacitor, just
                  the rectifier.
                  I retested the voltage on Pin 5 and determined that it is 24V DC. I
                  measured and confirmed continuity between both Pin 4 and Pin 5 and
                  the output positive terminal of the rotary switch with Plug 1
                  disconnected from the board. That is, there is NO AC going to my
                  control board. Except for the missing C1, my board looks just like
                  your photo.

                  Thanks for your diagnosis of the failed T1 and fried RY1, RY2, RY3
                  relays. This is what I had surmised. However, we have no chance of
                  getting replacement parts for months yet.

                  I have now have components for my "manual control" box and will hook
                  this up today and make sure everything works.

                  Ian,
                  That is great news about the new Dessalator board that actually does
                  what it is supposed to do. Do they have a name or part number for it?
                  Did you get it from Amel or Dessalator?

                  Ed


                  --- In amelyachtowners@yahoogroups.com, amelliahona <no_reply@...>
                  wrote:
                  >
                  > Judy: I will keep it on the forum as requested. I just didn't
                  want to
                  > bore anybody.
                  >
                  > I have used your old board to verify some of what I have written.
                  I
                  > have not attempted to fix it because I didn't have access to a 220
                  VAC
                  > 50 Hz power supply for testing, but now that I know that the board
                  > doesn't take 220 volts, I just need to verify the correct input
                  voltage
                  > and perhaps I can repair yours. Or at the very least I can bypass
                  the
                  > power supply part and verify the logic/relays work.
                  >
                  > On another note, I am now on page 8 of a Users Guide, including
                  > troubleshooting, photos of all components and specifications. I
                  will
                  > post parts of it in the files section as it is complete. Please
                  note
                  > any ammendments (notated in the header) when referencing this
                  > item as it is a work in progress. I have already updated the file
                  > entitled Logic Board Schematic.pdf to reflect the discoveries of
                  > yesterday.
                  >
                  > The NAIS JSI-12v relays on the logic board are $1.49 USD each and
                  > the T1 & T2 voltage regulators (Motorola 7812CT and 7805CT) are
                  > $0.39 USD each I just ordered ten of each for spares and trouble
                  > shooting.
                  >
                  > Happy sailing Judy,
                  >
                  > Gary
                  >
                  > "Judy" <sailingjudy@> wrote:
                  > >
                  > > Gary and Ed,
                  > >
                  > > I have been reading all of your posts with keen interest and am
                  trying
                  > > to produce a troubleshooting guide with all of the info.
                  > >
                  > > I would appresciate it if you kept your posts on the Amel forum,
                  or if
                  > > not, copy me at KE5FTK at winlink.org.
                  > >
                  > > Best,
                  > >
                  > > Bill Rouse s/v BeBe SM2 #387
                  > > sailing with Captain Judy in Curacao
                  >
                • amelliahona
                  Ed wrote: First, all of my voltage measurements were referenced to Pin 1 ground. Thanks for the clarifications. Second, I noticed that my board does not
                  Message 8 of 22 , Sep 9, 2007
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                    Ed wrote:

                    "First, all of my voltage measurements were referenced to Pin 1 ground."

                    Thanks for the clarifications.

                    "Second, I noticed that my board does not have the C1 capacitor"

                    That is interesting. It seems there are several versions of this board
                    out there. Perhaps Dessalator originally had an AC powered version
                    of their board. It never really made sense to me to have both
                    24 VDC and AC power on the board but that is what Dessalator told me
                    and originally I had no reason to doubt them. That coupled with
                    a full bridge rectifier/capacitor circuity on the board led me to
                    believe that what they said was true. JUST ONE FINAL THING TO
                    ILLUCIDATE - Where does the red wire to pin 4 come from. Can
                    you please physically trace it for me?

                    If there is only 24 VDC on the board then the rectifier really only
                    provides reverse voltage protection to the board. The input of
                    24 VDC to T1 would be an appropriate input voltage. T1 then
                    would put out the 12 volts for the relays RY1, RY2, RY3 and as
                    input to T2.

                    "we have no chance of getting replacement parts for months yet."

                    I have obtained the replacement parts for the relays and T1, T2. Total
                    cost for 8 of each was less than $20 USD. You might test the
                    relays by putting 12 volt DC across the terminal of the coils on
                    the board (rig up some flashlight batteries or some such and
                    see the files section for the relay pin configuration).

                    If the new Dessalator board works as advertised and they are willing
                    to provide documentation that might be the way to go. If you
                    would like replacement parts let me know and I will see what I
                    can do to try and get you some.

                    Let me know what you find out about the pin 4 red wire.

                    Thanks, Gary
                  • amelliahona
                    Hi Ed: Any chance you have had a moment to trace the red wire on Plug 1, Pin 4? If it indeed goes to the same point on the rotary switch as the red wire on
                    Message 9 of 22 , Sep 12, 2007
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                      Hi Ed:

                      Any chance you have had a moment to trace the red wire
                      on Plug 1, Pin 4? If it indeed goes to the same point on
                      the rotary switch as the red wire on pin 5 give me your
                      thoughts on why Dessalator would do that. Is it just a
                      jumper wire?

                      I have T1 spares, as well as some spare relays.
                      I could probably mail the voltage regulators to you in a
                      standard envelope, the relay might be another matter.

                      The latest schematic in the files section (revision 3) shows
                      the coils on RY1, RY2, RY3, and the data sheet in the files
                      section gives you the pin layout.

                      Thanks for the info.

                      Gary
                    • edmund_steele
                      Hi Gary, We have been at sea and just got to an internet connection again (Limassol, Cyprus). I did try to physically track both wires from pins 4 and 5
                      Message 10 of 22 , Sep 13, 2007
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                        Hi Gary,
                        We have been at sea and just got to an internet connection again
                        (Limassol, Cyprus). I did try to physically track both wires from
                        pins 4 and 5 without success. I will try again really HARD and let
                        you know.

                        BTW, the manual override of the control board works fine.
                        Ed

                        --- In amelyachtowners@yahoogroups.com, amelliahona <no_reply@...>
                        wrote:
                        >
                        > Hi Ed:
                        >
                        > Any chance you have had a moment to trace the red wire
                        > on Plug 1, Pin 4? If it indeed goes to the same point on
                        > the rotary switch as the red wire on pin 5 give me your
                        > thoughts on why Dessalator would do that. Is it just a
                        > jumper wire?
                        >
                        > I have T1 spares, as well as some spare relays.
                        > I could probably mail the voltage regulators to you in a
                        > standard envelope, the relay might be another matter.
                        >
                        > The latest schematic in the files section (revision 3) shows
                        > the coils on RY1, RY2, RY3, and the data sheet in the files
                        > section gives you the pin layout.
                        >
                        > Thanks for the info.
                        >
                        > Gary
                        >
                      • edmund_steele
                        Hi Gary, The wire from Pin 4, Plug 1 is paralleled to the wire from Pin 5, about an inch and half from the plug. The joint was buried right under the first
                        Message 11 of 22 , Sep 14, 2007
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                          Hi Gary,
                          The wire from Pin 4, Plug 1 is paralleled to the wire from Pin 5,
                          about an inch and half from the plug. The joint was buried right
                          under the first cable tie and well hidden.

                          Thank you for the kind offer of mailing spares. We are in cruising
                          mode and will be stopping at ports of entry and anchorages for just a
                          few days at most. We plan to winter in Marmaris, Turkey and fix all
                          then.
                          Best Regards,
                          Ed


                          --- In amelyachtowners@yahoogroups.com, "edmund_steele"
                          <edmundsteele@...> wrote:
                          >
                          > Hi Gary,
                          > We have been at sea and just got to an internet connection again
                          > (Limassol, Cyprus). I did try to physically track both wires from
                          > pins 4 and 5 without success. I will try again really HARD and let
                          > you know.
                          >
                          > BTW, the manual override of the control board works fine.
                          > Ed
                          >
                          > --- In amelyachtowners@yahoogroups.com, amelliahona <no_reply@>
                          > wrote:
                          > >
                          > > Hi Ed:
                          > >
                          > > Any chance you have had a moment to trace the red wire
                          > > on Plug 1, Pin 4? If it indeed goes to the same point on
                          > > the rotary switch as the red wire on pin 5 give me your
                          > > thoughts on why Dessalator would do that. Is it just a
                          > > jumper wire?
                          > >
                          > > I have T1 spares, as well as some spare relays.
                          > > I could probably mail the voltage regulators to you in a
                          > > standard envelope, the relay might be another matter.
                          > >
                          > > The latest schematic in the files section (revision 3) shows
                          > > the coils on RY1, RY2, RY3, and the data sheet in the files
                          > > section gives you the pin layout.
                          > >
                          > > Thanks for the info.
                          > >
                          > > Gary
                          > >
                          >
                        • Dr. Goodman
                          Forgive my ignorance--What is a TDS reading, and how is it obtained. Presumably it has to do with water purity? -- David Goodman email:
                          Message 12 of 22 , Sep 19, 2007
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                            Forgive my ignorance--What is a TDS reading, and how is it obtained.
                            Presumably it has to do with water purity?

                            --
                            David Goodman
                            email: drdavegoodman@...
                            cell: 608-772-0634
                            STT: 340-998-2169


                            [Non-text portions of this message have been removed]
                          • amelliahona
                            DAVID, THERE IS NO SUCH THING AS A DUMB QUESTION!!! Here is a site that will hopefully answer your question: http://www.simplyhydro.com/tds-ec.htm To quote
                            Message 13 of 22 , Sep 19, 2007
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                              DAVID, THERE IS NO SUCH THING AS A DUMB QUESTION!!!

                              Here is a site that will hopefully answer your question:

                              http://www.simplyhydro.com/tds-ec.htm

                              To quote from that site (which by the way is talking about plant nutrient solutions, but
                              which are the same principles as for sea water)

                              "TDS, EC, PPM, microSiemens: What do all those letters mean?

                              What is the best way to calibrate a TDS or Ec meter?
                              Answer: Standard reference solutions are used. The bottles are marked with the
                              conductivity (EC) value in microSiemens/cm and the corresponding ppM values for sodium
                              chloride (NaCl) and potassium chloride (KCl) solutions, and sometimes for a "442"
                              reference mixture. The conductivity of sodium chloride solutions is close to that of
                              hydroponic mineral nutrients, so a "1000 ppM NaCl" standard is most frequently used
                              when calibrating the meter for hydroponic solutions. You should follow the calibration
                              instructions in the manual which the manufacturer of your meter provided.

                              What does a TDS or EC meter measure?
                              Answer: The electrical conductivity (EC) of your nutrient results from motion of mineral
                              ions when the meter applies an electrical voltage. The ppM value of a sodium chloride
                              solution happens to be very close to half of its conductivity value (in microSiemens/cm), so
                              many meters display the conductivity as an equivalent NaCl amount.

                              What does the term parts per million (ppm) mean?
                              Answer: It is a common unit for measuring the concentration of elements in the nutrient
                              solution. One ppm is one part by weight of the mineral in one million parts of solution.

                              How do I convert between TDS and EC readings?
                              Answer: To obtain an approximate sodium chloride TDS value, multiply the EC reading (in
                              microSiemens/cm) by 1000 and divide by 2.

                              To get an EC value, multiply the ppm reading by 2 and divide by 1000.
                              Thus, if your EC is 1:
                              1*1000/2= 500 ppm.
                              And if your ppm is 500:
                              500*2/1000= 1 EC

                              Is it better to use an EC or a TDS meter?
                              Answer: If you have plant nutrient recommendations in EC units, an EC meter is
                              convenient. If your plant nutrient recommendations are in ppM values, a sodium chloride
                              TDS calibration is easier to use."

                              Hope this helps.

                              My EC meter usually shows about 500-550 microSiemens when the water maker is
                              running. It will start out at 550 and fall to as low as 460 after it has been running
                              for an hour or so. Water makers work better (at least the membranes do) when
                              they are used for prolonged periods frequently. Thus my water maker TDS readings
                              should be about 250 ppm.

                              Regards, Gary Silver, MD

                              --- In amelyachtowners@yahoogroups.com, "Dr. Goodman" <drdavegoodman@...> wrote:
                              >
                              > Forgive my ignorance--What is a TDS reading, and how is it obtained.
                              > Presumably it has to do with water purity?
                              >
                              > --
                              > David Goodman
                              > email: drdavegoodman@...
                              > cell: 608-772-0634
                              > STT: 340-998-2169
                              >
                              >
                              > [Non-text portions of this message have been removed]
                              >
                            • drdavegoodman
                              Dear Ian and Gary; I have looked at the Simply Hydroponics website that Gary referred me to and it did have the answers to my question. So I m getting one of
                              Message 14 of 22 , Sep 20, 2007
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                                Dear Ian and Gary;
                                I have looked at the Simply Hydroponics website that Gary referred me
                                to and it did have the answers to my question. So I'm getting one of
                                the TDS meters--good selection on ebay
                                Thanks!
                                Dave

                                --- In amelyachtowners@yahoogroups.com, amelliahona <no_reply@...> wrote:
                                >
                                > DAVID, THERE IS NO SUCH THING AS A DUMB QUESTION!!!
                                >
                                > Here is a site that will hopefully answer your question:
                                >
                                > http://www.simplyhydro.com/tds-ec.htm
                                >
                                > To quote from that site (which by the way is talking about plant
                                nutrient solutions, but
                                > which are the same principles as for sea water)
                                >
                                > "TDS, EC, PPM, microSiemens: What do all those letters mean?
                                >
                                > What is the best way to calibrate a TDS or Ec meter?
                                > Answer: Standard reference solutions are used. The bottles are
                                marked with the
                                > conductivity (EC) value in microSiemens/cm and the corresponding ppM
                                values for sodium
                                > chloride (NaCl) and potassium chloride (KCl) solutions, and
                                sometimes for a "442"
                                > reference mixture. The conductivity of sodium chloride solutions is
                                close to that of
                                > hydroponic mineral nutrients, so a "1000 ppM NaCl" standard is most
                                frequently used
                                > when calibrating the meter for hydroponic solutions. You should
                                follow the calibration
                                > instructions in the manual which the manufacturer of your meter
                                provided.
                                >
                                > What does a TDS or EC meter measure?
                                > Answer: The electrical conductivity (EC) of your nutrient results
                                from motion of mineral
                                > ions when the meter applies an electrical voltage. The ppM value of
                                a sodium chloride
                                > solution happens to be very close to half of its conductivity value
                                (in microSiemens/cm), so
                                > many meters display the conductivity as an equivalent NaCl amount.
                                >
                                > What does the term parts per million (ppm) mean?
                                > Answer: It is a common unit for measuring the concentration of
                                elements in the nutrient
                                > solution. One ppm is one part by weight of the mineral in one
                                million parts of solution.
                                >
                                > How do I convert between TDS and EC readings?
                                > Answer: To obtain an approximate sodium chloride TDS value, multiply
                                the EC reading (in
                                > microSiemens/cm) by 1000 and divide by 2.
                                >
                                > To get an EC value, multiply the ppm reading by 2 and divide by 1000.
                                > Thus, if your EC is 1:
                                > 1*1000/2= 500 ppm.
                                > And if your ppm is 500:
                                > 500*2/1000= 1 EC
                                >
                                > Is it better to use an EC or a TDS meter?
                                > Answer: If you have plant nutrient recommendations in EC units, an
                                EC meter is
                                > convenient. If your plant nutrient recommendations are in ppM
                                values, a sodium chloride
                                > TDS calibration is easier to use."
                                >
                                > Hope this helps.
                                >
                                > My EC meter usually shows about 500-550 microSiemens when the water
                                maker is
                                > running. It will start out at 550 and fall to as low as 460 after
                                it has been running
                                > for an hour or so. Water makers work better (at least the membranes
                                do) when
                                > they are used for prolonged periods frequently. Thus my water maker
                                TDS readings
                                > should be about 250 ppm.
                                >
                                > Regards, Gary Silver, MD
                                >
                                > --- In amelyachtowners@yahoogroups.com, "Dr. Goodman"
                                <drdavegoodman@> wrote:
                                > >
                                > > Forgive my ignorance--What is a TDS reading, and how is it obtained.
                                > > Presumably it has to do with water purity?
                                > >
                                > > --
                                > > David Goodman
                                > > email: drdavegoodman@
                                > > cell: 608-772-0634
                                > > STT: 340-998-2169
                                > >
                                > >
                                > > [Non-text portions of this message have been removed]
                                > >
                                >
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