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  • Looking to replace solar water heater

    I am looking to replace my solar hot water heater only. I have asked several companies for estimates but they all seem to want to sell me the whole system. Little bit nervous not sure where to buy as my home stores don't seem to have decent pricing or knowledge. I have replaced a conventional water heater before but not sure what steps to take for solar. Thank you very much in advance for any help that can be given.

    I live in Sunny Arizona this is what I have now.
    17 year old 82 Gallon State Solar/electric water heater w/ Goldline differential. Don't think I need such a large tank since I am only one person and don't use much hot water. I am open to just getting a conventional water heater w/ timer but would like to replace solar heater if I would get ROI in a decent time.

    I guess questions that I have are what would you do conventional 40 electric w/ timer or replace solar unit? I am only one person.
    Where can I find out more on how to replace solar unit. What all the pipes are and steps.
    Local stores only have one solar model its pretty expensive what are my options. Don't think I want to spend more than $800.
    If I detach glycol lines on top will it dump all over? Where do I get replacement glycol?
    Do I need to replace differential? If not how do I make sure its set up correctly. It has been messed with in the past.

    I have pictures of what I have here:




  • #2
    that is an indirect with an external heat exchanger. The other pipes going from the solar actually move the water from the tank and back.
    It is possible to take a standard 80 gallon electric tank and modify it to work.
    This entails removing the drain valve and replacing it with a T and feeding the cold water in there, removing the cold inlet nipple and dip tube and cutting it off so it ends about 1/3 of the way from the bottom off the tank.

    The other two pipes in the top of the tank are simply attached to dip tubes one at the bottom and one 1/3 of the way up.

    Is there another water heater as back up or is this a one tank affair.

    How many square feet of collector area do you have?
    NABCEP certified Technical Sales Professional

    [URL="http://www.solarpaneltalk.com/showthread.php?5334-Solar-Off-Grid-Battery-Design"]http://www.solarpaneltalk.com/showth...Battery-Design[/URL]

    [URL]http://www.calculator.net/voltage-drop-calculator.html[/URL] (Voltage drop Calculator among others)

    [URL="http://www.gaisma.com"]www.gaisma.com[/URL]

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    • #3
      Thanks for the heads up on that naptown, I am exited about this. It looks like I have a single 3x8. Is there a problem with using a 40 gallon tank with this? By reading the table on page 89 in article below it looks like I am right on the money for Arizona. Even having 25 gallons of solar storage would be enough for me I think with 15 gallons of electric backup.

      I found an article from Home Power magazine that talks about the modification that you are referring to. http://homepower.com/article/?file=HP96_pg88_Marken -
      One-Tank SDHW Storage with Electric Backup. I am going to read over these instructions and try to make sense of the layout of my system. I might have questions later. Does this set of instructions jive with what you are talking about?

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      • #4
        I have my water heater picked out will get it tomorrow. Bradford White Tall 50 Gal... $415 delivered.

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        • #5
          no need to mess with the glycol side

          Sounds like you have it figured out!

          Of course, the glycol pH should be tested every five years, and should stay above 7.

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          • #6
            Originally posted by Art VanDelay View Post
            Sounds like you have it figured out!

            Of course, the glycol pH should be tested every five years, and should stay above 7.
            I will have to look into how to flush it I am sure that it is bad by now being 17 years old more than likely.

            Does anyone know how the pumps would turn on and off? Do I have to reattach my differential for the new setup? How do I tell what settings to put it at?

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            • #7
              Originally posted by ardcarmvk View Post
              I will have to look into how to flush it I am sure that it is bad by now being 17 years old more than likely.

              Does anyone know how the pumps would turn on and off? Do I have to reattach my differential for the new setup? How do I tell what settings to put it at?
              Yes you will need to rescue the sensors from the tank and save for reinstallation in the new tank.

              As far as recharging goes you will need some glycol solution, a couple of buckets and a pump.
              If you have to buy all of the above it may be less expensive to call a local solar company to have this done.
              the pumps are a bit pricey to do this.
              NABCEP certified Technical Sales Professional

              [URL="http://www.solarpaneltalk.com/showthread.php?5334-Solar-Off-Grid-Battery-Design"]http://www.solarpaneltalk.com/showth...Battery-Design[/URL]

              [URL]http://www.calculator.net/voltage-drop-calculator.html[/URL] (Voltage drop Calculator among others)

              [URL="http://www.gaisma.com"]www.gaisma.com[/URL]

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              • #8
                Originally posted by ardcarmvk View Post
                I will have to look into how to flush it I am sure that it is bad by now being 17 years old more than likely.

                Does anyone know how the pumps would turn on and off? Do I have to reattach my differential for the new setup? How do I tell what settings to put it at?
                You don't need to change any settings.

                The old glycol might be fine. I doubt if a solar company would flush and refill for less than $300.

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                • #9
                  Originally posted by Art VanDelay View Post

                  The old glycol might be fine.
                  1. You may be able to rejuvenate it by using additives to correct the ph and restore the corrosion inhibitors, etc.
                  See http://www.epa.gov/osw/conserve/materials/antifree.htm for more info (not enough to tell you exactly what to do or where to get the additives though.)
                  2. If it needs to be replaced, the old glycol mix may be need to be disposed of as hazardous waste under applicable laws, but should be disposed of safely in any case. You can find disposal or recycling sites in the US (some free) at www.earth911.com.
                  SunnyBoy 3000 US, 18 BP Solar 175B panels.

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                  • #10
                    Thank you all for the continued support on this, I will look into refreshing glycol or pricing the flush after my install. Well tomorrow is the big day of my install. Very excited. I figured out that my tank is also too big to fit through the storage closet door. I'll work something out I am sure.

                    I looked into configuring my differential and it has way jacked settings now. The High limit is way down at 130 degrees and I will change it to 200 degrees. I found a nice article here. http://www.solarradiant.com/thermal/

                    Still have some last minute questions. Where is my mixing valve int he pictures that I provided and how will the sensors from the differential fit on my new water heater?

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                    • #11
                      This is why I am assuming is going to happen tomorrow. I will get more detailed pictures of current setup for my archive that I will keep. From my picture here: http://s1220.photobucket.com/albums/...e000000006.jpg I assume that the right is the cold water source I will probably replace or oil the valve since its nice and stiff. I assume the mixing valve is the dial on the left before it goes out to the house upper left to the wall. The one in the left back is the hot from the exchanger and the right back is cold to exchanger. I think thats all right, I just have to figure out where all the wires fit and are for. Even though I am not near the heater I expect one is from tank sensor to differential and one is from exchanger or collector sensor. Then I would have power to the tank and power to the differential. Am I all pretty correct here?

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                      • #12
                        Originally posted by ardcarmvk View Post
                        This is why I am assuming is going to happen tomorrow. I will get more detailed pictures of current setup for my archive that I will keep. From my picture here: http://s1220.photobucket.com/albums/...e000000006.jpg I assume that the right is the cold water source I will probably replace or oil the valve since its nice and stiff. I assume the mixing valve is the dial on the left before it goes out to the house upper left to the wall. The one in the left back is the hot from the exchanger and the right back is cold to exchanger. I think thats all right, I just have to figure out where all the wires fit and are for. Even though I am not near the heater I expect one is from tank sensor to differential and one is from exchanger or collector sensor. Then I would have power to the tank and power to the differential. Am I all pretty correct here?
                        I would change the glycol for sure. After 17 years, the reason it MIGHT be ok is that you had a big tank but the longest I have ever waited to change someones glycol is 10 years and it was pretty yucky. Unless I am blind, I don't see an expansion tank either.

                        If it is not too late, Bradford white has an 80gal tank with an electric element in the top and a heat exchanger in the bottom. You could get rid of your back up tank.

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                        • #13
                          Originally posted by ardcarmvk View Post
                          Thank you all for the continued support on this, I will look into refreshing glycol or pricing the flush after my install. Well tomorrow is the big day of my install. Very excited. I figured out that my tank is also too big to fit through the storage closet door. I'll work something out I am sure.

                          I looked into configuring my differential and it has way jacked settings now. The High limit is way down at 130 degrees and I will change it to 200 degrees. I found a nice article here. http://www.solarradiant.com/thermal/

                          Still have some last minute questions. Where is my mixing valve int he pictures that I provided and how will the sensors from the differential fit on my new water heater?
                          Don't change the High limit on the controller. I anything run it up to 140. you need to leave a bit of wiggle room on the high limit. 200 will not allow any room for stagnation and cooling when load is low.
                          Mixing valve should remain in the same relative position as it was on the outlet of the tank.
                          Sensors may require a bit o finagling to get them in the correct position. perhaps even cutting through the Jacket of the water heater at the top and inserting and reinsulating around it.
                          What controller do you have (resol?)
                          NABCEP certified Technical Sales Professional

                          [URL="http://www.solarpaneltalk.com/showthread.php?5334-Solar-Off-Grid-Battery-Design"]http://www.solarpaneltalk.com/showth...Battery-Design[/URL]

                          [URL]http://www.calculator.net/voltage-drop-calculator.html[/URL] (Voltage drop Calculator among others)

                          [URL="http://www.gaisma.com"]www.gaisma.com[/URL]

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                          • #14
                            Originally posted by MikeSolar View Post
                            I would change the glycol for sure. After 17 years, the reason it MIGHT be ok is that you had a big tank but the longest I have ever waited to change someones glycol is 10 years and it was pretty yucky. Unless I am blind, I don't see an expansion tank either.

                            If it is not too late, Bradford white has an 80gal tank with an electric element in the top and a heat exchanger in the bottom. You could get rid of your back up tank.
                            Yeah I already bought the 50 gallon according to the article for arizona and 24 sq ft x 2 gallons, 50 gallon should be okay. I don't have a back up tank just the one that I bought.

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                            • #15
                              Originally posted by Naptown View Post
                              Don't change the High limit on the controller. I anything run it up to 140. you need to leave a bit of wiggle room on the high limit. 200 will not allow any room for stagnation and cooling when load is low.
                              Mixing valve should remain in the same relative position as it was on the outlet of the tank.
                              Sensors may require a bit o finagling to get them in the correct position. perhaps even cutting through the Jacket of the water heater at the top and inserting and reinsulating around it.
                              What controller do you have (resol?)
                              Naptown, I have a old gold line gl-30 it has an extra dial "element interlock" that I do not know what it is. Interlock was the one that was @ 130 degrees. I have my high limit @ 170. Pics below.

                              So when you say cutting through the jacket of the heater that is the R-8 insulation that I am going to buy and not the 2" of heater insulation right? I am still having a problem seeing how the sensor installs.



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