<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML xmlns="http://www.w3.org/TR/REC-html40" xmlns:o = "urn:schemas-microsoft-com:office:office" xmlns:w = "urn:schemas-microsoft-com:office:word" xmlns:x = "urn:schemas-microsoft-com:office:excel"><HEAD><TITLE>Light fixtures</TITLE> <META http-equiv=Content-Type content="text/html; charset=iso-8859-1"> <META content="MSHTML 6.00.2800.1400" name=GENERATOR> <STYLE>@font-face { font-family: Helvetica; } @page Section1 {size: 8.5in 11.0in; margin: 1.0in 1.0in 1.0in 1.0in; } P.MsoNormal { FONT-SIZE: 12pt; MARGIN: 0in 0in 0pt; FONT-FAMILY: "Times New Roman" } LI.MsoNormal { FONT-SIZE: 12pt; MARGIN: 0in 0in 0pt; FONT-FAMILY: "Times New Roman" } DIV.MsoNormal { FONT-SIZE: 12pt; MARGIN: 0in 0in 0pt; FONT-FAMILY: "Times New Roman" } A:link { COLOR: blue; TEXT-DECORATION: underline } SPAN.MsoHyperlink { COLOR: blue; TEXT-DECORATION: underline } A:visited { COLOR: purple; TEXT-DECORATION: underline } SPAN.MsoHyperlinkFollowed { COLOR: purple; TEXT-DECORATION: underline } P { FONT-SIZE: 12pt; MARGIN-LEFT: 0in; MARGIN-RIGHT: 0in; FONT-FAMILY: "Times New Roman"; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto } SPAN.EmailStyle20 { FONT-WEIGHT: normal; COLOR: windowtext; FONT-STYLE: normal; FONT-FAMILY: "Times New Roman"; TEXT-DECORATION: none; mso-style-type: personal-reply } DIV.Section1 { page: Section1 } </STYLE> </HEAD> <BODY lang=EN-US style="WORD-WRAP: break-word; khtml-nbsp-mode: space; khtml-line-break: after-white-space" vLink=purple link=blue> <DIV> Hi Dave,<o:p></o:p>  <o:p></o:p> you raise a good point, I'm no authority, but will share what I think I know about overlapping thresholds, then hope someone in the know will set us both straight. <o:p></o:p>  <o:p></o:p> 1.) This may be a stretch, but I've been told a proven method to regulate the temperature of blood resource in a blood bank, is to cycle slightly warmer and cooler air through the storage unit, overlapping in the critical temperature range.<o:p></o:p>  <o:p></o:p> Why they can't simply dial in a thermostat at the temperature they want, and a get stable temperature... I don't know, I'm not an engineer. <o:p></o:p>  <o:p></o:p> 2.) Closer to home; over winter, I finally completed the heating/cooling system (ductwork, furnace, etc.) at our cottage. Tom K., our mechanical plant supervisor suggested the most efficient operation (we heat it all winter) is having the furnace-fan run at low-speed continually, with the furnace actively cycling in warm air in as required, rather have everything shut off until it gets cold, then try heat it all up again. Make's sense, and it works!  <o:p></o:p> Granted Dave, neither of us are enthalpy control experts (I sure ain’t), but I hope we realize piano climate systems don't "force" humidity in or out, that should be fairly obvious. You might find a conversation I had with Bill Spurlock about water-damaged pianos helpful: <o:p></o:p>  <o:p></o:p> Bill explained that warming and circulating air adjacent to moist wood creates a gradient, or in simple terms makes the air a more inviting destination for the moisture, than the wood is. This gradient invites the moisture to change directions, and move towards the more welcoming environment.<o:p></o:p>  <o:p></o:p> Likewise, to restore equilibrium moisture content to wood, simply provide moist air in the vicinity... no “forcing” required. If the wood is dry it will accept moisture, if it isn't, it won't.  By the way the most satisfying explanation I’ve ever encountered on this subject was the class Roger Wheelock gave at the Dallas Convention. Roger of course is a scientist, and Bill I believe, has an engineering background. Isn’t it nice the PTG has such good resources, so we don’t have to “guess” about this stuff?<o:p></o:p>  <o:p></o:p> As for tempering the climate around pianos, I think all we’re really trying to do Dave, is maintain the equilibrium moisture content in the wood (soundboard), to keep the piano at pitch and prevent damage.  And it seems we can do this quite successfully, using the products you mention, to maintain a compatible range of relative humidity in the air.<o:p></o:p>  <o:p></o:p> An “Inconvenient Truth” as you and I both know, is if relative humidity isn’t stable, the moisture content of the wood will not be stable (“Nature’s Law,” not ours), and if the wood isn’t stable, neither is the tuning, no matter the manufacturer, the day of the week, where you live, who tuned it, or which foot they stood on.  <o:p></o:p>  <o:p></o:p> (I used to think piano owners/sales persons were the biggest perpetrators of "piano-tuning myths,” but you might be surprised at the fanciful notions some of “us” have cultivated… myself included!? Yipes! ;>) <o:p></o:p>  <o:p></o:p> Anyhow, people who understand wood, know “the rules,” and hopefully we do too, since pianos are made of wood. For what we don’t know, it’s fortunate to have a wealth of knowledge and experience in the technology and manufacturing fields we can rely on. <o:p></o:p>  <o:p></o:p> best regards,<o:p></o:p> Mark Cramer,<o:p></o:p> Brandon University<o:p></o:p>    <o:p></o:p> PS Regarding things that “do” work:<o:p></o:p>  <o:p></o:p> Last year ago I sent a post about fitting a soundboard cover to a KG-3c, in a church that had 30-cent seasonal pitch swings, despite having a Dampp-Chaser with one 50w and two 25w dehumidifiers. <o:p></o:p>  <o:p></o:p> I tuned the same piano this morning, and was pleased to find the tenor just 6 cents sharp, and the rest of the piano right on the button!     <o:p></o:p>  <o:p></o:p>  <o:p></o:p>  <o:p></o:p>   <o:p></o:p>    <o:p></o:p>    <o:p></o:p> That’s the one thing (or one of the things) that I don’t get about these systems.  I’m fortunate that our climate here is sufficiently benign that we don’t have any systems installed.  As the system is currently designed, it forces humidity into the piano – even when the ambient humidity is high – and then forces it out.  To me it would make more sense to have the humidifier come on at say 35% and the dehumidifier to come on at 50% (45%??) but in between those it would leave the poor piano alone!  Or in the summer if your humidity is high, just disconnect the humidifier and the opposite in the winter.  What good is it to continually humidify then dehumidify the piano probably several times a day?<o:p></o:p>  <o:p></o:p> dave<o:p></o:p> David M. Porritt <A href="mailto:dporritt@smu.edu">dporritt@smu.edu</A>  <o:p></o:p></DIV> <BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px"> <DIV class=OutlookMessageHeader dir=ltr align=left>-----Original Message----- From: caut-bounces@ptg.org [mailto:caut-bounces@ptg.org]On Behalf Of Porritt, David Sent: Thursday, June 08, 2006 10:19 AM To: College and University Technicians Subject: Re: [CAUT] Topping up the tank </DIV> <DIV class=Section1> Jeff Tanner wrote:<o:p></o:p> <DIV> <o:p> </o:p></DIV> <DIV>  … and even in these high humidity summers the tanks need filling more often than every two weeks -- more like a week to 10 days.<o:p></o:p></DIV> <DIV> <o:p> </o:p></DIV> <DIV> <DIV> That’s the one thing (or one of the things) that I don’t get about these systems.  I’m fortunate that our climate here is sufficiently benign that we don’t have any systems installed.  As the system is currently designed, it forces humidity into the piano – even when the ambient humidity is high – and then forces it out.  To me it would make more sense to have the humidifier come on at say 35% and the dehumidifier to come on at 50% (45%??) but in between those it would leave the poor piano alone!  Or in the summer if your humidity is high, just disconnect the humidifier and the opposite in the winter.  What good is it to continually humidify then dehumidify the piano probably several times a day?<o:p></o:p> <o:p> </o:p> dave<o:p></o:p></DIV> David M. Porritt<o:p></o:p></DIV> <A href="mailto:dporritt@smu.edu">dporritt@smu.edu</A><o:p></o:p></DIV></BLOCKQUOTE></BODY></HTML>