<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <html> <head> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; = charset=iso-8859-1"> <meta name=Generator content="Microsoft Word 10 (filtered)"> <style>  </style> </head> <body lang=EN-US link=blue vlink=blue> <div class=Section1> I guess they do that so that it = isn’t clicking on and off constantly. If you set it for 30% I imagine it = takes it down to 30% and then shuts off. It doesn’t turn on again until = it hits 35%. You could set it 2.5% below your target which would have it = fluctuating 2.5% above and 2.5% below and give you an average RH over time of your = target. Since it takes a certain amount of time for the wood to lose or gain = moisture you would expect the range of the corresponding EMC to be somewhat less = than 5% which would put it in an acceptable range of your target, I would = presume. That’s, of course, assuming that they are accurate.   <div> David Love davidlovepianos@comcast.net </div> -----Original = Message----- From: = pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On Behalf Of Farrell Sent: Monday, January 23, = 2006 4:05 PM To: Pianotech = List Subject: Re: Humidistat = for Wood conditioning box   <div> That web site states = "The differential between the on and off points is fixed at 5% RH", = which means the environment will vary 5%, depending on where it is in the on/off = cycle. A decent thermostat will keep the environment within a degree or so and = thus keeps the RH next to perfectly constant. </div> <div>   </div> <div> I had considered this = subject humidistat and others also. I'm glad I stuck with the simple thermostat. = It reall is easy to use and works very well. </div> <div>   </div> <div> Terry = Farrell </div> <div>   </div> <div> ----- Original Message = ----- </div> <div>   </div> <div> >> I found this = humidistat that I would use for a wood conditioning box >> that seems to be fairly good but expensive ($290).  Anyone = have any >> experience with it or can you suggest one that works as well = for less >> $$$.  It’s the RHC that I’m looking = at—scroll down to the second unit. >> >> <a = href="http://www.greenair.com/humidistat.htm">http://www.greenair.com/humi= distat.htm</a> >> >> David Love > > > If you're conditioning wood for soundboard building, +-5%RH is > pretty miserable accuracy. If you set it at 30%RH and 90°F = looking > for 6%MC, you could get anywhere from 5.2%-6.7%. Of course, if > that's just calibration accuracy, and repeatability within a narrow = > range is good (which they never seem to think is important enough = to > mention) you can offset the reading and be pretty close. I assume = > that's what the mentioned 5% "set differential" is for. = So even a > cheap humidistat can work well if it makes the same mistake with = > dependable repeatability. > > Ron N </div> </div> </body> </html>