More about humidity control

[Bob Anderson]

With respect to Lance Laforgue's comments about the lack of sensitivity
of Dampp-Chaser humidistats, I can only say that I haven't experienced
that problem. If I could keep the RH within a range of 6%(46% to 52%) on
all the pianos I service I would be one extremely happy camper. 

If you live in a very humid place, Lance, and find yourself constantly
adding water to the D-Ch. humidifier, the likely problem is a poor
placement of the humidistat resulting in improper feedback from the
humidifier, or even having the humidifier plugged into the dehumidifier
outlet on the humidistat. Although I live in a desert area, the humidity
in July and August is fairly high (the RH in my shop in the early
morning has been over 80% for the last week, and I haven't added water
to the humidifier in the piano in there since early July), and neither I
nor any of my customers who have the systems use much water during this
time span. In fact, customers notice how little water they're using and
sometimes wonder if the systems are working. They always are. They just
don't use any water if the humidity is high enough.

Bob Anderson
Tucson,AZ