Open letter to Dampp Chaser

[Wallace Scherer]

Dear Bob Mair,

I read with interest your response to Frank Leister's letter in which he
expressed his concern over the seemingly improper functioning of the Dampp
Chaser system he has installed on his Steinway grand piano.

As a piano technician who has installed several Dampp Chaser systems
through the years, I too am concerned over what to me also seems like a
design problem. At least let me suggest a simple fix.

Frank stated, "it seems like the system is fighting itself."

I certainly had no idea that one of the two parts is heating at all times.
You stated, "Either the humidifier will be on or the dehumidifier(s) will
be on.  There will never be a time when both are on at the same time. 
Likewise, there will never be a time when neither one is on."

I would definitely agree with Frank that the system is fighting itself. It
certainly seems to me that once the DE-humidifier has reduced the relative
humidity inside the piano case sufficiently, the humidistat would cut it
off and do nothing for at least five minutes, maybe ten. This would give
enough time for the heat to dissipate and the humidistat to measure the
ambient humidity to determine if further control is necessary. The same
scenario would be true for the humidifier.

I certainly don't believe that Dampp Chaser systems are ONLY installed in
pianos that are located in places where the ambient humidity is NEVER at
the proper level. Certainly SOME pianos are located in places where the
ambient humidity is SOMETIMES at the correct level. At those times, the
system should not be doing anything except MONITORING. Neither the
humidifier nor the dehumidifier needs to be cycled on.

With all the stock electronic circuitry available, a timing device that
would WAIT ten minutes between cycles would be no big thing to include. For
the customer, a handy dandy indicator light panel would be helpful: A blue
light to indicate when the humidity is too low and the humidifier is on, a
green light to indicate when the humidity is OK and neither is on, and a
pink light to indicate when the humidity is too high and the dehumidifier
is on. (These colors would go along with the pink and blue spots on the
little humidity indicator cards that you distribute and that we sometimes
give to our customers.)

Well, thanks for listening. I really hope that this perceived problem will
be fixed soon so I can feel more comfortable about recommending the
complete Dampp Chaser humidity control system to my customers.

Sincerely,

Wally Scherer, Norfolk, VA
E-mail: WallyTS@compuserve.com
Web page: http://www.geocities.com/Vienna/2411 
"Old piano tuners never die - they just go beatless."