A while back I tuned a little K&C console in a church that (I found out later) had a swamp-type AC unit (in Florida!). I tuned it to A440. Two weeks later, after they moved the piano from the swamp-type church to the new church sanctuary with a compressor-type AC unit, the pianist called to complain that the piano had gone out of tune. I went out to the church and sure enough, it was a bit out of tune - it ranged from 30 to 80 cents FLAT! After looking all over the piano for a broken plate strut or anything else that might explain the pitch drop, I finally got to talk with Pastor who mentioned the old building that was always clammy, etc. I had never seen anything like that, and have not since. Terry Farrell ----- Original Message ----- From: "Keith Roberts" <kpiano@goldrush.com> To: "Pianotech" <pianotech@ptg.org> Sent: Friday, June 27, 2003 10:33 AM Subject: Air conditioning > > > Reminds me of the argument between two technicians about whether > > air conditioning lowered relative humidity or raised it. They > > were both right, only one was in Arizona and the other in Florida. > > There are two different types of cooling air conditioners. A > freon/compressor type which will dry the air out and is a closed system (no > outside air). > Correct me please if this next statement is wrong. Air which is already dry > and can't get much drier will have a higher RH at 80* than 100*. (* means > degrees F ). > RH around here (gold country, California) dropped to 8% these last > couple of days. The skin cracks in an air conditioned house. So I'm not sure > if the RH goes up at all. I know it does when the temperature starts to drop > in the evening. > The other type is an evaporative (swamp) cooler. It is an open system > and windows need to be open to not back pressure the blower. They will not > work in a humid enviroment as there is no room for the water to evaporate. > At 100* outside with a RH of 20%, a swamp cooler will blow 75* air with a RH > of 70%. At the piano (mine) the RH was 47%. > I recommend people put in a swamp cooler around here even if they have > the other type of air conditioning. It can be ducted instead of sitting in > the window and is cheaper than adding a humidifier to the compressor type. > It is a more pleasing air and far cheaper to run than the compressor type. > The compressor type becomes a fine back up on the five (maybe) days a year > the swamp cooler doesn't work. > Keith Roberts > > > > > _______________________________________________ > pianotech list info: https://www.moypiano.com/resources/#archives
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