<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"><base href="x-msg://1665/"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Crispin,<div><br></div><div>I have not explore controls for air flows with natural draft units. Clearly both secondary and primary air could be controlled by variable aperture air supplies. The Big Green Egg and some Weber units offer this.</div><div><br></div><div>I just have not tried it .... yet.</div><div><br></div><div>Obviously the multi-speed fan powered units have turn down ratios.</div><div><br></div><div>One take away is that it would probably be good to have independent controls for both Primary and Secondary air regardless of the nature of the draft - forced or natural. In my experience, stove performance is very sensitive to the interaction of the two.</div><div><br></div><div>Regards,</div><div><br></div><div>Jock</div><div><br></div><div><br></div><div><br></div><div><br><div><div>On May 23, 2013, at 12:36 PM, Crispin Pemberton-Pigott <<a href="mailto:crispinpigott@gmail.com">crispinpigott@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div lang="EN-CA" link="blue" vlink="purple" style="font-family: Arial; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div class="WordSection1" style="page: WordSection1; "><div style="margin: 0mm 0mm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">Dear Jonathan<o:p></o:p></span></div><div style="margin: 0mm 0mm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span></div><div style="margin: 0mm 0mm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">That is a nice set of devices with many new avenues explored.<o:p></o:p></span></div><div style="margin: 0mm 0mm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span></div><div style="margin: 0mm 0mm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">I have a question:<o:p></o:p></span></div><div style="margin: 0mm 0mm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span></div><div><div><div style="margin: 0mm 0mm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">Can any of these units be controlled so the cook can regulate the heat getting into the pot?<o:p></o:p></span></div><div style="margin: 0mm 0mm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); "> </span></div><div style="margin: 0mm 0mm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">Thanks<br>Crispin in Ulaanbaatar<o:p></o:p></span></div></div><div><div style="margin: 0mm 0mm 0.0001pt; font-size: 12pt; font-family: 'Times New Roman', serif; "><span style="font-size: 9pt; font-family: Helvetica, sans-serif; "> </span></div></div></div></div>_______________________________________________<br>Stoves mailing list<br><br>to Send a Message to the list, use the email address<br><a href="mailto:stoves@lists.bioenergylists.org" style="color: purple; text-decoration: underline; ">stoves@lists.bioenergylists.org</a><br><br>to UNSUBSCRIBE or Change your List Settings use the web page<br><a href="http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org" style="color: purple; text-decoration: underline; ">http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org</a><br><br>for more Biomass Cooking Stoves, News and Information see our web site:<br><a href="http://stoves.bioenergylists.org/" style="color: purple; text-decoration: underline; ">http://stoves.bioenergylists.org/</a></div></blockquote></div><br></div></body></html>