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    <p>Jason,</p>
    <p>This is the way thermal shock was explained to me. Thermal shock
      creates micro fractures in the glass. PV modules have tough
      tempered glass so one thermal shock event, or a few dozen events,
      is unlikely to cause a module to fracture; but eventually the
      glass gets to the last straw when the micro fractures connect to
      each other and the whole pane breaks up. You can't do much about
      sun showers but you can certainly avoid spraying the hose on hot
      glass.</p>
    Kent Osterberg<br>
    Blue Mountain Solar <br>
    <p><br>
    </p>
    <div class="moz-cite-prefix">On 10/20/2023 1:47 PM, Jason Szumlanski
      via RE-wrenches wrote:<br>
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    <blockquote type="cite" cite="mid:CAE438R8k4=4cywkyXYfRiKW27cGRq-oE6htz1_82k2T+4MTbpw@mail.gmail.com">
      
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        <div>I don't understand the thermal shock nonsense. It routinely
          starts downpouring here when it's blazing hot out (sun
          showers) and the rain is way cooler than ground water in
          summer. It makes no sense. If hose water from the ground is
          going to hurt solar panels, you better not put them where it
          rains! 
          <div dir="auto"><br>
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          <div dir="auto">I replied privately to Dana, but for the
            benefit of the group, it takes a heavy soiling to make any
            appreciable difference. I have done numerous tests at times
            of high pollen and found little to no benefit to cleaning
            solar panels. Certainly it would not be worth paying someone
            to do it. Other climates may have different results. My
            suggestion would be to test first. Module level power
            electronics can provide incontrovertible proof.</div>
          <div dir="auto"><br>
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          <div dir="auto">Jason</div>
          <div dir="auto"><br>
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          <br>
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            <div dir="ltr" class="gmail_attr">On Fri, Oct 20, 2023, 4:21
              PM Dave Tedeyan via RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org" moz-do-not-send="true" class="moz-txt-link-freetext">re-wrenches@lists.re-wrenches.org</a>>
              wrote:<br>
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              <div dir="ltr">Hi Dana, 
                <div><br>
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                <div>See attached from REC. I would imagine these
                  guidelines would apply to all modules.</div>
                <div>Cheers,</div>
                <div>Dave</div>
              </div>
              <br>
              <div class="gmail_quote">
                <div dir="ltr" class="gmail_attr">On Fri, Oct 20, 2023
                  at 3:56 PM Dana Orzel via RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank" rel="noreferrer" moz-do-not-send="true" class="moz-txt-link-freetext">re-wrenches@lists.re-wrenches.org</a>>
                  wrote:<br>
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                        <p class="MsoNormal"><span style="font-size:14pt;font-family:"Century
                            Gothic",sans-serif">Hey ally ‘all,</span></p>
                        <p class="MsoNormal"><span style="font-size:14pt;font-family:"Century
                            Gothic",sans-serif"> </span></p>
                        <p class="MsoNormal"><span style="font-size:14pt;font-family:"Century
                            Gothic",sans-serif">Ok bad solar
                            installer! 7 years & I have never
                            cleaned my modules & live on a dirt
                            road. Yeah rain does a good job with the
                            dust but there is a film mostly on the
                            edges.</span></p>
                        <p class="MsoNormal"><span style="font-size:14pt;font-family:"Century
                            Gothic",sans-serif"> </span></p>
                        <p class="MsoNormal"><span style="font-size:14pt;font-family:"Century
                            Gothic",sans-serif">What does everyone
                            do for cleaning?</span></p>
                        <p class="MsoNormal"><span style="font-size:14pt;font-family:"Century
                            Gothic",sans-serif"> </span></p>
                        <p class="MsoNormal"><span style="font-size:14pt;font-family:"Century
                            Gothic",sans-serif">My array is 16’+
                            tall on a hill side. I have a pressure
                            washer & was going to pick up a large
                            sponge type mop & mount it on a painters
                            extension pole. </span></p>
                        <p class="MsoNormal"><span style="font-size:14pt;font-family:"Century
                            Gothic",sans-serif"> </span></p>
                        <p class="MsoNormal"><span style="font-size:14pt;font-family:"Century
                            Gothic",sans-serif">Good Biodegradable
                            cleaning solutions?</span></p>
                        <p class="MsoNormal"><span style="font-size:14pt;font-family:"Century
                            Gothic",sans-serif"> </span></p>
                        <p class="MsoNormal"><span style="font-size:14pt;font-family:"Century
                            Gothic",sans-serif"> </span></p>
                        <p class="MsoNormal"><span style="font-size:12pt;font-family:"Century
                            Gothic",sans-serif">_________________________________________________________</span></p>
                        <p class="MsoNormal"><span style="font-size:12pt;font-family:"Century
                            Gothic",sans-serif;color:rgb(56,86,35)">Dana
                            Orzel                </span><span style="font-size:12pt;font-family:"Century
                            Gothic",sans-serif;color:rgb(56,86,35)">GREAT
                            SOLAR WORKS!                      </span></p>
                        <p class="MsoNormal"><span style="font-size:12pt;font-family:"Century
                            Gothic",sans-serif;color:rgb(56,86,35)">C
                            – 208.721.7003      E – <a href="mailto:dana@solarwork.com" target="_blank" rel="noreferrer" moz-do-not-send="true"><span style="color:rgb(56,86,35);text-decoration:none">dana@solarwork.com</span></a></span></p>
                        <p class="MsoNormal"><span style="font-size:12pt;font-family:"Century
                            Gothic",sans-serif;color:rgb(56,86,35)">W
                            - www. <a href="http://greatsolarworks.com" target="_blank" rel="noreferrer" moz-do-not-send="true">greatsolarworks.com</a>    
                            <a href="http://www.solarwork.com/" target="_blank" rel="noreferrer" moz-do-not-send="true"><span style="color:rgb(56,86,35);text-decoration:none">www.solarwork.com</span></a></span></p>
                        <p class="MsoNormal"><i><u><span style="font-size:12pt;font-family:"Century
Gothic",sans-serif;color:rgb(56,86,35)">“Responsible Technologies
                                for Responsible People since 1988!”</span></u></i></p>
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