Out of Tune Yamaha Upright

[Terry Beckingham]

Hello list,

I have a Yamaha upright piano located in a church. I am not sure of the
model number but it is about 45 to 46 inches high. The piano is only about 3
years old. It goes out of tune badly in the tenor section in only about a
month after being tuned.

As the RH in the church must vary considerably when the church is filled
with people breathing out moist air on Sundays, I believed it was a humidity
problem. I installed a 5 part dampp chaser system in this piano about a
month ago.

I just had a call this morning that the tenor section is badly out of tune
again. Does anyone have any suggestions as to what could be causing this?

The piano is about three feet from an outside wall. The church is fairly new
and does not appear to be drafty. There is no heat source near the piano.
The temperature in the church is kept at a constant 68 degrees F.

Any suggestions would be much appreciated. Thanks in advance

Terry Beckingham
PTG Associated