Dave, we started by-passing our humidifier tanks last summer, and have done the same for this summer, for several of the very same reasons you mention. We (the student assistants) un-plug the humidifer, remove the tank, empty and clean it, and install new pads. If repairs are needed, the tank goes to the shop, if not, it is left hanging by two hooks (to indicate it's out of service) until fall. We use Radio Shack "test clamps" to short the LWL so the water light won't flash, and have painted-out all the "pads" lights with black nail polish. I'm not ready to draw conclusions as to how well the pianos fare, after just one summer of trial, however, the pitch of most practice pianos was quite good last fall, when tanks we're re-installed. The sketchy logic behind my decision is that during seasons when avg. RH is above 42%, dehumidifying wil be the dominant cycle (as you note). When the low humidity threshold is finally, if ever reached, the humidifier will NOT be available to return RH to the upper threshold. However, there seems to be plenty of ambient humidity to take care of that. Anyone find otherwise? Pressure Ridges, etc.: Regarding manufacturing processes and rcommendations, it seems helpful to divide things into two areas of responsibility: the manufacturer's, and the owners. The manufacturer's responsiblity is to determine the Wood Moisture Content the wood will be milled, assembled and finished at, then provide the owner with the corresponding range of RH required to keep it that way. i.e: If Steinway does their work at X% WMC, then they might tell the owner something like "your job is to keep the RH between XX and XX%." If the makers have done their job, and the owner does theirs, the WMC will remain at X%. i.e: the wood will remain at the identical dimensions at which it was original milled, assembled and glued... no pressure ridges, no cracks. (ever notice manufacturers always seem to specify a "range" rather than a pinpoint RH spec? It always seems to correspond very close to the upper/lower thresholds indicated on a Dampp-Chaser Humidistat) At Banff, where we anticipate below average RH year around, we always work our wood at a 5% WMC, and haven't a failure that I can recall (either pressure ridges or cracks). IOW, we select (take an educated guess at...) the WMC that matches the average range of RH. Mind you, in a "perfect world" neither Banff nor Brandon would ever drop below 11 degrees F, even in January. Yup, like that's gonna happen! ;>) ciao, Mark C. Mark: > > > > Thanks for your reply. The word "Forced" was not a good choice in my > original post. "Makes available" would probably be better. I just know > that if I were in a more extreme climate where humidification were > essential I would probably try to avoid the constant tank filling during > the summer if possible. Filling the tanks, changing the pads, etc. is a > lot of work! > > > > We have a couple of rooms where excess humidity is sometimes a problem > but for the most part our building stays quite good. I do worry more > about high humidity than low. Most of our grand pianos are Steinways > and since they dry their panels so much I've always thought they did > well in the dryness. When humidity is high the boards tend to develop > compression ridges which then crack the next time the humidity goes > down. I've always thought that if we keep them on the drier side, they > don't develop as many problems. > > > > We did get down to 11-degrees (F) once this year and that's pretty rare > but the temperature was back up long before our building had a chance to > react in any way. I know that 11-degrees would be a treat for you in > January! > > > > I do think someone should do more research on the idea of having the > system "off" when the relative humidity is in the correct zone. I also > realize that would probably demand humidistats with much higher accuracy > than what is currently available. > > > > dave > > > > David M. Porritt > >
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