[CAUT] Hygrometers

[Ed Sutton]

How about the "Professional" meter that Pianotek sells?
I like it because it reads quickly and reads lower RH than the Radio Shack types.
I haven't compared it to a sling psychrometer. The sling psychrometers I have found were rather expensive.
Ed Sutton

  ----- Original Message ----- 
  From: John Musselwhite 
  To: College and University Technicians 
  Sent: Thursday, November 15, 2007 4:41 PM
  Subject: Re: [CAUT] Hygrometers


  At 12:42 PM 11/15/07, Paul wrote:


    Hi List, 

    I have a couple of those cheap  max-min thermo-hygro readers from Pianotek.  I'm not sure if they're very accurate.  

  They're more accurate than the Radio Shack ones, but I don't think by much.


    If you all remember, last fall/winter I sent in some photos of one of our recital rooms that Richard West took before I got here with the fog and water dripping all over everything.  It hasn't been that bad since I've been here, but the last couple of times I've gone in there this past week, it feels really muggy, but the hygrometer only registers 40-45% (which would be ideal).  Any suggestions on who makes a real accurate reader? 

  We have the opposite problem here where Rh can be down into the single digits in mid-winter. None of the "standard" humidity gauges go down that far. I use a Cooper Digital Psychrometer much like the one down the page at http://www.techinstrument.com/acatalog/Hygrometers__RH___humidity_.html   (SAMJR995). It's a digital version of a "sling psychrometer", the wet/dry bulb unit we use to make truly accurate RH readings. While it's supposedly accurate +-5% it still reads down to zero Rh which in worst case might actually be 5%. I've read as low as 3% in mid-winter here in some churches. In those pianos with DC's installed, sticking it under the rim for a minute and pressing the "hold" button shows it's in the 40-43% range at the soundboard even with extremely low humidities outside the instrument.

  I also have a USB recording hygrometer that will track the RH and temp over a long period of time. It's at http://www.measurementcomputing.com/cbicatalog/USB-502.asp?dept_id=414&pf_id=1759 . It reads very much like the "standard" units and differs from the Psychrometer's readings. I trust the Cooper more for truly accurate readings.

                   John



  -------------------------------
  John Musselwhite, RPT  -  Registered Piano Technician
  Musselwhite Piano Services - Calgary, Alberta Canada
  Office/cel (403) 246-7717 Fax (403) 255-5268
  Outside of Calgary call Toll Free:  1-866-95-PIANO (1-866-957-4266)
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