<html> <body> Wim, I've got an S&S D here with an undercover and a piano cover.  The control on DCs works well.  It took the undercover to get the darn thing to stabilize. Andrew Anderson At 12:41 PM 5/22/2008, you wrote: <blockquote type=cite class=cite cite="">One of my client has a small grand with a Piano Disc sitting in the living room, overlooking the ocean. The dealer suggested to her to keep the PD turned on all the time to help keep the moisture away. The piano also has a string cover to protect the strings. When she called to set up an appointment she mentioned that she and her husband go the mainland for 2 or 3 months at a time, several times a year, and wanted to know what else she could do to protect her new piano. I suggested a full piano cover, which she is getting.  I asked the dealer if he thought leaving the PD turned on the whole time she is gone would be a good idea, especially with a full piano cover, and he said no. So I want to put a DC under the piano. But most DC are on pianos that are open, so the air can circulate. So my question is, would the heat of the DC do damage to a piano that has a full cover on it? Because of the constant wind from the ocean, the temperature in the house doesn't fluctuate too much, from about 75 - 80. Willem (Wim) Blees, RPT Piano Tuner/Technician Honolulu, HI Author of The Business of Piano Tuning available from Potter Press <a href="http://www.pianotuning.com/" eudora="autourl"> www.pianotuning.com</a> <hr> Stay informed, get connected and more <a href="http://mobile.aol.com/productOverview.jsp?productOverview=aol-mobile-overview&?ncid=aolmbd00030000000139"> with AOL on your phone</a>. </blockquote></body> </html>