Humidistat Accuracy

[Isaac OLEG]

Dave,

I don't understand why a high end hygrometer could be only given for
7%. I have the kind of tool sold as that and it is said 5% (and a not
so expensive one may be)

But indeed a psychrometer is not expensive and more accurate.

I bet accuracy is not the good world when it comes to hygrometers
actually, because of the relation between temperature and humidity
reading.

Are you sure of the plugging ?

I believe it is possible to the damp chaser to be reasonably working ,
may be not at 42 % particularly if the place is very dry or very
humid, but you describe a situation where nothing really works. I'd
suggest that the damping elements may be not enough to act, may be the
opening of the hygrometer is dirty, or misplaced. I understand there
is some latency between the heating humidifier works and between the
drying rods works. Can't remember why in regard of the official
explanations.

Id think the systems are prerequisites in a very humid situation, but
I don't believe much in the moisting part, and they probably only cut
high ends anyway

 I would send them back to the dealer for "calibration" the units.

in a 75-80% situation, I installed a 3 rods system this spring, and it
seem to do its job fine after a few hours.
Did not see the actual results, I will in a few weeks.

Let us know what it gives please.

Regards.

Isaac OLEG

> -----Message d'origine-----
> De : pianotech-bounces@ptg.org
> [mailto:pianotech-bounces@ptg.org]De la
> part de Dave Doremus
> Envoye : dimanche 1 decembre 2002 05:38
> A : Pianotech
> Objet : Re: Humidistat Accuracy
>
>
> 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
>
>
> -----------------------------
> Dave Doremus RPT
> New Orleans
> algiers_piano@bellsouth.net
> ------------------------------
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