<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=iso-8859-1"><meta name=Generator content="Microsoft Word 14 (filtered medium)"><style><!--
/* Font Definitions */
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri","sans-serif";
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-family:"Calibri","sans-serif";}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:14.0pt'>Hello,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt'>I have an older 10 collector system in which the glycol has stagnated due to a defective collector sensor, apparently for some time. I was able to drain the collectors, the cooked glycol is black with a good bit of sediment. I tried to flush the system with water but my ½ hp utility pump could not pump the water entirely through the collectors. Suction slowed down and stopped after just a few gallons, as if the pump couldn’t overcome the effective head of the system. I had no problem using this pump to charge the loop when it was commissioned. I suspect the collectors may be gummed up with cooked glycol. I guess compressed air is next to try. Are there any safe chemicals to use to purge / un-gum the collectors? Thanks. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='font-size:14.0pt'>Kirk Herander<o:p></o:p></span></b></p><p class=MsoNormal><b><span style='font-size:14.0pt'>VT Solar, LLC <o:p></o:p></span></b></p><p class=MsoNormal><b><i><span style='font-size:14.0pt'>Proven PV provider since 1991<o:p></o:p></span></i></b></p><p class=MsoNormal><b><span style='font-size:14.0pt'><a href="www.vermontsolarnow.com">www.vermontsolarnow.com</a><o:p></o:p></span></b></p><p class=MsoNormal><span style='font-size:14.0pt'>dba Vermont Solar Engineering<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt'>NABCEP<sup>TM </sup>Inaugural Certificant<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt'>VT RE Incentive Program Partner<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt'>802.863.1202<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>