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<DIV><FONT face=Arial size=2>Hello List,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Bob Mair, CEO of Dampp-Chaser Corp., =
has asked me
to post the following related to the recent thread on humidistat
accuracy.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Thanks!</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Roger</FONT></DIV>
<DIV><FONT size=2><FONT face=Arial></FONT> </DIV>
<DIV>
<P>Don Rose has hit the nail right on the head in his 12/01/02 response =
to
Terry.</P>
<P>Stand alone Dehumidifiers normally are rated in amps and those that =
we
routinely use are 6.3 amps and 7.5 amps. I don’t think they go much =
higher. I
have seen 5.3 amp units and may have at some point in the distant past =
seen 3.9
amp units.</P>
<P>If you want to convert amps to watts you can use the rough rule of =
thumb that
1 amp equals 120 watts. Again, more for information than anything else,
Dampp-Chaser Humidistats are rated at 200 watts max for the Dehumidifier =
side,
20 watts for the Humidifier side. They contain essentially the same =
switch that
was used years ago, so they are capable of withstanding an overload. =
However,
they are not designed to control a Dehumidifier rated at 6.3 amps steady =
state
that draws 6 times that during start up. Particularly when start up can =
occur a
number of times each day in a piano application.</P>
<P>On hygrometers, Klaus Fenner wrote an article for the Piano =
Technicians
Journal, sometime in the late 1980's, describing what all manufacturers =
of
"hair" hygrometers know, and for the most part are willing to =
acknowledge. After
operating in the same RH level for a substantial period of time they get =
"lazy"
and won’t move out of this level even when the RH level demands that =
they do so.
They require "exercising" to bring them back to proper operation. Lufft
hygrometers are sold with instructions on exercising. They call it =
recalibration
but it, in fact, is exercising. Be careful when using your "hair" =
hygrometer
that it has not become lazy. If anyone is interested in the Klaus Fenner =
article, let me know and I’ll make you a copy.</P>
<P>I believe our promotional literature describes our System as =
maintaining an
AVERAGE RH level of 42%, not a maximum 42%. On this subject, does anyone =
read
our Newsletter? We sent 15,000 Newsletters out this past June that =
contained an
article on Humidistat testing. It had 2 great pictures showing =
Humidistat switch
testing and some very good explanation. The following is a portion of =
the
article:</P>
<P><B>Creates its own Environment</P>
<DIR>
<DIR>
<P>How the Humidistat switch works:</B> The electromechanical switch has =
a
polymer band which swells as the relative humidity rises and shrinks =
when the
relative humidity falls. During testing, computers monitor and register =
the
<B>set points</B> at which each switch changes from the humidifying to =
the
dehumidifying mode. Our specifications regarding set points: the high =
event must
be no higher than 51.5%, the low event no lower than 39.0% with a =
differential
no greater 8%.</P></DIR></DIR>
<P><B>04502-C0425 57</B></P>
<P>Time degF %R Evnt</P>
<P>1510 81.3 57.8 High</P>
<P>2044 81.0 42.1 Low</P>
<P>0437 81.3 48.3 High</P>
<DIR>
<DIR><B>
<P>Above, an actual switch test record.</B> This is a recording of the =
action of
each switch which is made during a 16 hour test period. The "042502" on =
the
record is April 25, 2002 (the date of testing is on all Humidistats). =
Throughout
the test, the temperature fluctuated between 81.0F and 81.3F. As the =
test began,
the relative humidity was 57.8%. To test the switch in the =
Humidification mode,
the RH was lowered, and at 42.1%, this switch energized the Humidifier. =
In our
terminology, 42.1% is the lower set point. The chamber then =
automatically began
raising the humidity to simulate the conditions in a piano when the =
Humidifier
is operating. As humidity increased, the polymer band swelled until an =
upper set
point of 48.3% relative humidity was reached. At that point, the switch
energized the Dehumidifier and shut off the Humidifier. The switch in =
the table
above had a differential of 6.2%, which is well within our standards. =
<B>The
narrow differential produces a narrow range of relative humidity which =
forces
the soundboard to stabilize at a constant moisture content, regardless =
of room
humidity levels. In this way, the System creates its own environment =
within the
piano.</P></B></DIR></DIR>
<P>Now perhaps the most important part of this message is: We have a =
great
technical support section at Dampp-Chaser and are happy to help any and =
all.
It’s far more beneficial (and easier) to talk about a Technicians =
specific
problem over the phone than it is by way of email. If something isn’t =
going
right or you think it’s not going right, call us. That is why we are =
here. The
number is 1-800-438-1524. Ask for Bob, Mitch or
Roger.</P></FONT></DIV></BODY></HTML>