Humidistat Accuracy

Dave Doremus algiers_piano@bellsouth.net
Sat, 30 Nov 2002 22:38:02 -0600


At 9:30 PM -0500 11/30/02, Farrell wrote:
>I have a big pile of copies of a full-color beautiful Damp-Chaser 
>marketing handout that describes how the use of their dehumidifier 
>system keeps the relative humidity (RH) of the atmosphere in the 
>area of the piano soundboard at maximum of 42% RH.


Terry, This is a pet peeve of mine. I have just the last two weeks 
had two dampp chaser control units running in a customers house 
plugged into light bulbs. He has a curious mind and got the units 
with a rebuild that I did not do. (The piano has many problems still 
but that's another story.) One does not start to dry until the room 
humidity is over 70%, anywhere below 60% it tries to add water. The 
other one is always drying, never shuts off at New Orleans humidity. 
I had 30% in my shop yesterday, the lowest since last winter, he told 
me the unit was still heating. He has a fairly high end hygrometer, 
still only accurate to 7%, and is talking about a sling psychrometer. 
Meanwhile the dampp-chasers are only lighting the room. Neither is 
accurate enough to be in a piano. I have two humidistats at home that 
I hope to experiment on this week, but I dont think they are 
wonderful devices unless you have no other option. You'd be better 
off with room humidity control, IMHO.
-- 
----Dave


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Dave Doremus RPT
New Orleans
algiers_piano@bellsouth.net
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