[CAUT] Topping up the tank

[Porritt, David]

Mark:

 

Thanks for your reply.  The word "Forced" was not a good choice in my
original post.  "Makes available" would probably be better.  I just know
that if I were in a more extreme climate where humidification were
essential I would probably try to avoid the constant tank filling during
the summer if possible.  Filling the tanks, changing the pads, etc. is a
lot of work!  

 

We have a couple of rooms where excess humidity is sometimes a problem
but for the most part our building stays quite good.  I do worry more
about high humidity than low.  Most of our grand pianos are Steinways
and since they dry their panels so much I've always thought they did
well in the dryness.  When humidity is high the boards tend to develop
compression ridges which then crack the next time the humidity goes
down.  I've always thought that if we keep them on the drier side, they
don't develop as many problems.  

 

We did get down to 11-degrees (F) once this year and that's pretty rare
but the temperature was back up long before our building had a chance to
react in any way.  I know that 11-degrees would be a treat for you in
January!  

 

I do think someone should do more research on the idea of having the
system "off" when the relative humidity is in the correct zone.  I also
realize that would probably demand humidistats with much higher accuracy
than what is currently available.

 

dave

 

David M. Porritt

dporritt at smu.edu

________________________________

From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of
Mark Cramer
Sent: Friday, June 09, 2006 2:16 PM
To: College and University Technicians
Subject: Re: [CAUT] Topping up the tank

 

Hi Dave,

 

you raise a good point, I'm no authority, but will share what I think I
know about overlapping thresholds, then hope someone in the know will
set us both straight. 

 

1.) This may be a stretch, but I've been told a proven method to
regulate the temperature of blood resource in a blood bank, is to cycle
slightly warmer and cooler air through the storage unit, overlapping in
the critical temperature range.

 

Why they can't simply dial in a thermostat at the temperature they want,
and a get stable temperature... I don't know, I'm not an engineer. 

 

2.) Closer to home; over winter, I finally completed the heating/cooling
system (ductwork, furnace, etc.) at our cottage. Tom K., our mechanical
plant supervisor suggested the most efficient operation (we heat it all
winter) is having the furnace-fan run at low-speed continually, with the
furnace actively cycling in warm air in as required, rather have
everything shut off until it gets cold, then try heat it all up again.
Make's sense, and it works!

 

Granted Dave, neither of us are enthalpy control experts (I sure ain't),
but I hope we realize piano climate systems don't "force" humidity in or
out, that should be fairly obvious. You might find a conversation I had
with Bill Spurlock about water-damaged pianos helpful: 

 

Bill explained that warming and circulating air adjacent to moist wood
creates a gradient, or in simple terms makes the air a more inviting
destination for the moisture, than the wood is. This gradient invites
the moisture to change directions, and move towards the more welcoming
environment.

 

Likewise, to restore equilibrium moisture content to wood, simply
provide moist air in the vicinity... no "forcing" required. If the wood
is dry it will accept moisture, if it isn't, it won't.  By the way the
most satisfying explanation I've ever encountered on this subject was
the class Roger Wheelock gave at the Dallas Convention. Roger of course
is a scientist, and Bill I believe, has an engineering background. Isn't
it nice the PTG has such good resources, so we don't have to "guess"
about this stuff?

 

As for tempering the climate around pianos, I think all we're really
trying to do Dave, is maintain the equilibrium moisture content in the
wood (soundboard), to keep the piano at pitch and prevent damage.  And
it seems we can do this quite successfully, using the products you
mention, to maintain a compatible range of relative humidity in the air.

 

An "Inconvenient Truth" as you and I both know, is if relative humidity
isn't stable, the moisture content of the wood will not be stable
("Nature's Law," not ours), and if the wood isn't stable, neither is the
tuning, no matter the manufacturer, the day of the week, where you live,
who tuned it, or which foot they stood on.  

 

(I used to think piano owners/sales persons were the biggest
perpetrators of "piano-tuning myths," but you might be surprised at the
fanciful notions some of "us" have cultivated... myself included!?
Yipes! ;>) 

 

Anyhow, people who understand wood, know "the rules," and hopefully we
do too, since pianos are made of wood. For what we don't know, it's
fortunate to have a wealth of knowledge and experience in the technology
and manufacturing fields we can rely on. 

 

best regards,

Mark Cramer,

Brandon University

   

PS Regarding things that "do" work:

 

Last year ago I sent a post about fitting a soundboard cover to a KG-3c,
in a church that had 30-cent seasonal pitch swings, despite having a
Dampp-Chaser with one 50w and two 25w dehumidifiers. 

 

I tuned the same piano this morning, and was pleased to find the tenor
just 6 cents sharp, and the rest of the piano right on the button!     

 

 

 

  

   

   

That's the one thing (or one of the things) that I don't get about these
systems.  I'm fortunate that our climate here is sufficiently benign
that we don't have any systems installed.  As the system is currently
designed, it forces humidity into the piano - even when the ambient
humidity is high - and then forces it out.  To me it would make more
sense to have the humidifier come on at say 35% and the dehumidifier to
come on at 50% (45%??) but in between those it would leave the poor
piano alone!  Or in the summer if your humidity is high, just disconnect
the humidifier and the opposite in the winter.  What good is it to
continually humidify then dehumidify the piano probably several times a
day?

 

dave


David M. Porritt

dporritt at smu.edu

 

	-----Original Message-----
	From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org]On
Behalf Of Porritt, David
	Sent: Thursday, June 08, 2006 10:19 AM
	To: College and University Technicians
	Subject: Re: [CAUT] Topping up the tank

	Jeff Tanner wrote:

	 

	 ... and even in these high humidity summers the tanks need
filling more often than every two weeks -- more like a week to 10 days.

	 

	That's the one thing (or one of the things) that I don't get
about these systems.  I'm fortunate that our climate here is
sufficiently benign that we don't have any systems installed.  As the
system is currently designed, it forces humidity into the piano - even
when the ambient humidity is high - and then forces it out.  To me it
would make more sense to have the humidifier come on at say 35% and the
dehumidifier to come on at 50% (45%??) but in between those it would
leave the poor piano alone!  Or in the summer if your humidity is high,
just disconnect the humidifier and the opposite in the winter.  What
good is it to continually humidify then dehumidify the piano probably
several times a day?

	 

	dave

	
	David M. Porritt

	dporritt at smu.edu

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