variable humidistats

[DAMPPCHASR@aol.com]

Mitch Kiel,

     We don't purposely supply an adjustable humidistat because it can be
adjusted by anyone and once this is done you don't know where you are,
calibration wise.  Try it with a an adjustable room humidifier or
dehumidifier.  See if you can get to the calibration point you want
consistantly.  Don't settle for something 5% RH off.  Get right to it.  Look
at what you are using to calibrate with.  See how accurate it is and in
particular, how accurate it is guaranteed to be over a long period of time.
     Now that you have it calibrated, let it opperate for six months.  If
something goes astray (the piano isn't doing what you think it should), ask
who has been messing with the adjustment.  Someone may have or it may be that
something else has taken place.  You are just not sure. At any rate, you
adjust it to what you think will make it opperate where you think it should
and you start all over again.
     This doesn't particularly address the Dolman humidistat that you
describe but your question gave me the opportunity to share why we don't make
adjustable humidistats.
     On the subject of more closely matching the control to the ambient RH
level, we supply 2 additional calibration settings (in addition to the
standaard unit) to do this.  We supply a wet humidistat calibrated 6% (48% RH
average) higher than standard and a dry humidistat 4% (38% RH average) lower
than standard.  Could we do a humidistat at a level other than these?  Yes,
and would be happy to do so if there was a demand for it.

Bob Mair,
Dampp-Chaser Electronics