Climate Control Promotion

[Delwin D Fandrich]

----- Original Message -----
From: "Farrell" <mfarrel2@tampabay.rr.com>
To: <pianotech@ptg.org>
Sent: January 15, 2001 10:28 AM
Subject: Re: Climate Control Promotion


> Hi John. I like the DC systems quite a bit, but I am disappointed on the
> accuracy of their humidistats. Have you ever put the min/max hygrometer
next
> to the humidistat and checked it for a lengthy period of time (also good
to
> monitor room RH at the same time)? Also a good excercise is to plug an old
> electric clock (no digital) into the humidistat to see how long it runs
over
> a period of time.
>
> My own observations with many humidistats is that rather than turning on
and
> off within a few % of 42% RH, the regular calibration humidistats turn on
> and off in the 57% to 65% range. I wish I could keep my pianos in the 42%
> range.
>
> Terry Farrell
---------------------------------------------------

Terry,

Have you checked the accuracy of your hygrometer? The most common type --
i.e., those available through Pianotek, etc. -- are generally not all that
accurate. Relative humidity is a very difficult thing to measure with any
accuracy. It will cost you several hundreds of $$$ to get one that will have
certified accuracy much better than +/- 5% or so. I've checked a couple of
the inexpensive digital hygrometers against my sling hygrometer and have
found them to off as much as 20%.

Still, while I trust the sling hygrometer, it is real difficult to get an
accurate reading from it right up next to the soundboard.  So, I would
suggest checking the digital against a sling from time to time and making up
a correction chart. While the inexpensive digitals may not be all that
accurate, they do seem to be reasonably repeatable.

Del