Hello list, I have been travelling outside the US on business and it is not always so easy to get email, so it is just now that I am able to read of all the interest in Dampp-Chaser. I am Roger Wheelock, Vice President of Dampp-Chaser Corp. and will do my best to respond to the technical issues under discussion. We develop our Systems using actual averages of sound board moisture content in pianos in our research test rooms. We maintain test rooms at a constant 70% and constant 20% relative humidity (RH). Without a Climate Control System the moisture content of the soundboard varies when exposed to these extreme environments from a high of about 11% (at 70% RH) to a low of about 5% (at 20% RH). With a System installed soundboard moisture content range is reduced from 6% to 1% or less. Some of our best systems will show 7.5% average soundboard moisture content when the test room environment is at 70% RH and only drop to 7.3% average soundboard moisture content when the test room environment is changed to 20% RH. It is this control of soundboard moisture content that provides pitch stability to the piano, and allows a technician to perform a finer, higher quality tuning after the System has been installed. The System actually creates its own environment within the body of the piano. An electromechanical switch with a humidity sensor band ensures that the dehumidifier and the humidifier continally cycle while the system is operating. This provides the control to maintain a constant environment even if the room environment is very humid or very dry. The switches in the humidistat are all precailibrated in another test room at the factory. Here, in a twenty hour period the humidity is gradually raised to around 60% RH and then lowered to 30% RH. Computers record the high and low set points for the switch. Switches are calibrated as necessary to ensure that specifications are met for either a normal, wet or dry humidistat. The average of the two set points falls in the following ranges for each type of humidistat. Normal = 42-44% RH Wet = 48-50% RH Dry = 36-38% RH Each humidistat has differential between the low and high set point of less than 8% RH. The wet humidistat is designed for pianos which have been in a humid environment for a long time. The dry humidistat is designed for pianos which have been in a dry environment for a long time. Regarding dehumidifiers, we recommend a 50 watt and two 25 watt dehumidifiers for a grand piano which is longer than 6 feet 10 inches, a 50 watt and a 25 watt dehumidifier for smaller grand pianos, and a 50 watt dehumidifier for vertical pianos. If any of you have further questions please contact me directly. I can be reached for the next seven days at DamppChaser@compuserve.com. After that I can be reached at roger@dampp-chaser.com. Thanks, Roger
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