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Humidistat Accuracy

  • 1.  Humidistat Accuracy

    Posted 11-30-2002 19:30 
    From "Farrell" <mfarrel2@tampabay.rr.com>

I have a big pile of copies of a full-color beautiful Damp-Chaser marketing handout that describes how the use of their dehumidifier system keeps the relative humidity (RH) of the atmosphere in the area of the piano soundboard at maximum of 42% RH. Why is it that when I place the probe of my NIST-certified 1% accuracy hygrometer on top of my Damp-Chaser humidistat, it reads 55% RH? When I place the probe on top of the soundboard it reads 55%. When I place the probe in the middle of the room where the piano resides, it reads 55%. The heater rods are not warm. The atmosphere next to the soundboard should be 42%. The room and  everywhere else around the piano is 55% RH. The humidistat should turn on at.......something near 42% RH.  I'm looking at the pretty graph:  http://www.dampp-chaser.com/main.html  It suggests that RH won't even come close to 55%. Where is the discrepancy?

Terry Farrell


  • 2.  Humidistat Accuracy

    Registered Piano Technician
    Posted 11-30-2002 21:38 
    From Dave Doremus <algiers_piano@bellsouth.net>

At 9:30 PM -0500 11/30/02, Farrell wrote:
>I have a big pile of copies of a full-color beautiful Damp-Chaser 
>marketing handout that describes how the use of their dehumidifier 
>system keeps the relative humidity (RH) of the atmosphere in the 
>area of the piano soundboard at maximum of 42% RH.


Terry, This is a pet peeve of mine. I have just the last two weeks 
had two dampp chaser control units running in a customers house 
plugged into light bulbs. He has a curious mind and got the units 
with a rebuild that I did not do. (The piano has many problems still 
but that's another story.) One does not start to dry until the room 
humidity is over 70%, anywhere below 60% it tries to add water. The 
other one is always drying, never shuts off at New Orleans humidity. 
I had 30% in my shop yesterday, the lowest since last winter, he told 
me the unit was still heating. He has a fairly high end hygrometer, 
still only accurate to 7%, and is talking about a sling psychrometer. 
Meanwhile the dampp-chasers are only lighting the room. Neither is 
accurate enough to be in a piano. I have two humidistats at home that 
I hope to experiment on this week, but I dont think they are 
wonderful devices unless you have no other option. You'd be better 
off with room humidity control, IMHO.
-- 
----Dave


-----------------------------
Dave Doremus RPT
New Orleans
algiers_piano@bellsouth.net
------------------------------


  • 3.  Humidistat Accuracy

    Posted 12-01-2002 08:16 
    From "Farrell" <mfarrel2@tampabay.rr.com>

The sling hygrometer is fine for the room RH, but not much use to determine the RH right next to the underside of the soundboard (unless you have a 9' Brambach with no framing!). Before I bought my high-end hygrometer, I had run my shop dehumidifier off several regular DC humidistats and several "DRY" DC humidistats. The regular ones would turn the dehumidifier on around 60% to 65%. The "DRY" ones would be a bit better, switching the dehumidifier on in the upper 50%s. Now with my better hygrometer, I see that my cheap hygrometers now read two or three percent high, so I guess my stated ranges should be a bit lower. Still though, it appears we are not close to low-40%s.

Now that I have a good hygrometer, I will make some new observations of humidistat performance.

BTW. I have a Sear basement-type dehumidifier in my shop (900 square feet). It has an "electronic humidistat" - whatever that might be - that you can set to a range of desired humidity levels - the range extends down to 40% RH. I keep mine set at 45% and keep a small fan on top of the dehumidifier to keep air circulating so that it gets a good average shop-RH exposure. I have been very impressed with its performance. Every time I check RH in the shop with my new hygrometer, it reads between 43% and 45%.

A few humidistats I ran across on the web:

Johnson Controls $130

Microprocessor controlled unit http://www.greenair.com/humidistat.htm

http://www.meaco.com/conservation_heating_humidistat.htm

http://www.saginomiya.co.jp/english/e_products/rle.html

BTW - here is a room humidifier for those in dry climates:  http://www.powerhousecatalog.com/product/481/

I don't know the price of most of these. I know also I have seen a couple in lab equipment catalogs - I think they were in the $200 to $300 range. I think to be fair, we must acknowledge that DC sells their humidistats at a VERY low price. I think that we, as piano technicians trying to provide some target environmental conditions for a piano, must decide for ourselves whether the DC humidistat performs adequately, or if some other humidistat might better meet our needs. Realize that most good ones cost quite a bit more than a DC. The problem I have with DC is their claim of maintaining 42% RH. I haven't observed it yet.

Terry Farrell
  

    
                                                
    
					
                                                    

        
                                                
				
    
                                                
    
                                                    
                                                        
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  • 4.  Humidistat Accuracy

    Registered Piano Technician
    Posted 12-01-2002 11:14 
    From Don <pianotuna@accesscomm.ca>

Hi Terry,

One reason you are getting weird readings is that the dc controller was
never intended for high wattage units like stand alone dehumidifiers. I
suspect that each time the unit cycles the contacts inside "weld"
themselves together giving you a much higher *off* cycle.

Where did you get your "high end" humidstat?

At 10:16 AM 12/1/02 -0500, you wrote:
>The sling hygrometer is fine for the room RH, but not much use to
determine the RH right next to the underside of the soundboard (unless you
have a 9' Brambach with no framing!). Before I bought my high-end
hygrometer, I had run my shop dehumidifier off several regular DC
humidistats and several "DRY" DC humidistats. The regular ones would turn
the dehumidifier on around 60% to 65%. The "DRY" ones would be a bit
better, switching the dehumidifier on in the upper 50%s.

Regards,
Don Rose, B.Mus., A.M.U.S., A.MUS., R.M.T., R.P.T. Tuner for the Center of
the Arts

mailto:pianotuna@accesscomm.ca

http://us.geocities.com/drpt1948/

3004 Grant Rd.
REGINA, SK
S4S 5G7
306-352-3620 or 1-888-29t-uner


  • 5.  Humidistat Accuracy

    Posted 12-01-2002 13:23 
    From "Farrell" <mfarrel2@tampabay.rr.com>

It is indeed rated for high wattage units like a stand alone dehumidifier. I don't have a DC humidistat in front of me, but it has an amp rating. I seem to recall they are rated up to 600 watts at 120 volts. The dehumidifier power consumption (500-some watts) is just below the rating for the humidistat - so that should be OK. 

I bought a Pacer Model DH50 (Digital Hygro-Thermometer), http://www.pacer-ind.com/hygrometers/dh50.html  The specs say accurate to within 2%, but reportedly, most units test to within 1% accuracy. The test results that came with mine indicate that it was within 0.7% accuracy RH, over the operational scale range of 5% to 95% RH. I will send it to the manufacturer on a yearly basis for recalibration.

Terry Farrell
  

    
                                                
    
					
                                                    

        
                                                
				
    
                                                
    
                                                    
                                                        
                                                        Original Message


  • 6.  Humidistat Accuracy

    Registered Piano Technician
    Posted 12-01-2002 14:18 
    From Don <pianotuna@accesscomm.ca>

Hi Terry,

Motors *draw* far more on start up than the "rated" amounts. The amp rating
on the new humidistat is much lower than the old *brown* units (15 amps for
them). So welding is still quite possible. BTW where did u find a
dehumidifier that was only rated at 500 watts????? Mine is much much higher
than that.

At 03:23 PM 12/1/02 -0500, you wrote:
>It is indeed rated for high wattage units like a stand alone dehumidifier.
I don't have a DC humidistat in front of me, but it has an amp rating. I
seem to recall they are rated up to 600 watts at 120 volts. The
dehumidifier power consumption (500-some watts) is just below the rating
for the humidistat - so that should be OK. 


Regards,
Don Rose, B.Mus., A.M.U.S., A.MUS., R.M.T., R.P.T. Tuner for the Center of
the Arts

mailto:pianotuna@accesscomm.ca

http://us.geocities.com/drpt1948/

3004 Grant Rd.
REGINA, SK
S4S 5G7
306-352-3620 or 1-888-29t-uner


  • 7.  Humidistat Accuracy

    Posted 12-01-2002 00:49 
    From "Isaac OLEG" <oleg-i@wanadoo.fr>

Dave,

I don't understand why a high end hygrometer could be only given for
7%. I have the kind of tool sold as that and it is said 5% (and a not
so expensive one may be)

But indeed a psychrometer is not expensive and more accurate.

I bet accuracy is not the good world when it comes to hygrometers
actually, because of the relation between temperature and humidity
reading.

Are you sure of the plugging ?

I believe it is possible to the damp chaser to be reasonably working ,
may be not at 42 % particularly if the place is very dry or very
humid, but you describe a situation where nothing really works. I'd
suggest that the damping elements may be not enough to act, may be the
opening of the hygrometer is dirty, or misplaced. I understand there
is some latency between the heating humidifier works and between the
drying rods works. Can't remember why in regard of the official
explanations.

Id think the systems are prerequisites in a very humid situation, but
I don't believe much in the moisting part, and they probably only cut
high ends anyway

 I would send them back to the dealer for "calibration" the units.

in a 75-80% situation, I installed a 3 rods system this spring, and it
seem to do its job fine after a few hours.
Did not see the actual results, I will in a few weeks.

Let us know what it gives please.

Regards.

Isaac OLEG

> -----Message d'origine-----
> De : pianotech-bounces@ptg.org
> [mailto:pianotech-bounces@ptg.org]De la
> part de Dave Doremus
> Envoye : dimanche 1 decembre 2002 05:38
> A : Pianotech
> Objet : Re: Humidistat Accuracy
>
>
> At 9:30 PM -0500 11/30/02, Farrell wrote:
> >I have a big pile of copies of a full-color beautiful Damp-Chaser
> >marketing handout that describes how the use of their dehumidifier
> >system keeps the relative humidity (RH) of the atmosphere in the
> >area of the piano soundboard at maximum of 42% RH.
>
>
> Terry, This is a pet peeve of mine. I have just the last two weeks
> had two dampp chaser control units running in a customers house
> plugged into light bulbs. He has a curious mind and got the units
> with a rebuild that I did not do. (The piano has many
> problems still
> but that's another story.) One does not start to dry until the room
> humidity is over 70%, anywhere below 60% it tries to add water. The
> other one is always drying, never shuts off at New Orleans
> humidity.
> I had 30% in my shop yesterday, the lowest since last
> winter, he told
> me the unit was still heating. He has a fairly high end hygrometer,
> still only accurate to 7%, and is talking about a sling
> psychrometer.
> Meanwhile the dampp-chasers are only lighting the room. Neither is
> accurate enough to be in a piano. I have two humidistats at
> home that
> I hope to experiment on this week, but I dont think they are
> wonderful devices unless you have no other option. You'd be better
> off with room humidity control, IMHO.
> --
> ----Dave
>
>
> -----------------------------
> Dave Doremus RPT
> New Orleans
> algiers_piano@bellsouth.net
> ------------------------------
> _______________________________________________
> pianotech list info: http://www.ptg.org/mailman/listinfo/pianotech
>


  • 8.  Humidistat Accuracy

    Posted 12-01-2002 02:42 
    From "Isaac OLEG" <oleg-i@wanadoo.fr>

May be Damp chaser changed something in their model lately ?

I've send back one unit yet, but I don't installed so many, only one
system recently and it seem to work, even if it begin with higher
humidity that you describe.

I checked yet a unit with the electronic hygrometers I have and it was
10% 15% accurate env. don't remember the exact numbers
In a fluctuation situation, that should work enough well I guess.

Regards.

Isaac OLEG



> -----Message d'origine-----
> De : pianotech-bounces@ptg.org
> [mailto:pianotech-bounces@ptg.org]De la
> part de Farrell
> Envoy? : dimanche 1 d?cembre 2002 03:30
> ? : pianotech@ptg.org
> Objet : Humidistat Accuracy
>
>
> I have a big pile of copies of a full-color beautiful
> Damp-Chaser marketing handout that describes how the use of
> their dehumidifier system keeps the relative humidity (RH)
> of the atmosphere in the area of the piano soundboard at
> maximum of 42% RH. Why is it that when I place the probe of
> my NIST-certified 1% accuracy hygrometer on top of my
> Damp-Chaser humidistat, it reads 55% RH? When I place the
> probe on top of the soundboard it reads 55%. When I place
> the probe in the middle of the room where the piano
> resides, it reads 55%. The heater rods are not warm. The
> atmosphere next to the soundboard should be 42%. The room
> and  everywhere else around the piano is 55% RH. The
> humidistat should turn on at.......something near 42% RH.
> I'm looking at the pretty graph:
> http://www.dampp-chaser.com/main.html  It suggests that RH
> won't even come close to 55%. Where is the discrepancy?
>
> Terry Farrell
> _______________________________________________
> pianotech list info: http://www.ptg.org/mailman/listinfo/pianotech
>


  • 9.  Humidistat Accuracy

    Posted 12-01-2002 04:14 
    From "Isaac OLEG" <oleg-i@wanadoo.fr>

Generally accepted is the fact that even a simple hair hygrometer that
one can build himself , as
http://www.inrp.fr/lamap/activites/objets_techniques/idees/technique/a
ir_vent/hygrometre.htm

is accurate at 5% once well regulated.

I have such a commercial system in my workshop  (with a tall 25 cm
hair) to add a little internal pressure (with an air drier) when the
humidity is too high (it flow dry air in the place from another room)

The system is very reactive and I feel I can maintain the wanted
environment (around 50% actually)

What I don't get is that the different electronic hygrometers I have
all give readings that look similar at 5% or 7% more or less.
I suspect that the accuracy of the electronic systems is may be good
in a little medium zone, but far less in the high and low ranges

I believe too that the capacity used in the cheap circuits find in the
hygrometers and such electronic devices, is always reacting the same
way, and differently than hair hygrometers that gives too another
reading that a psychrometer.
Richard, may be chiming in, as he seem to be knowing more than me
about these facts.
Mostly they may be more precise at a certain temperature level than
another, we are asking an actually very small element to react to
difference of tension induced by the absorption of humidity, and this
change with the air pressure, the temperature...
This is asking a lot to these small parts.

Psychometric measure can be done with only one thermometer, and 2
readings, one wet and one dry. Did not do that really, but I
understand the psychrometers are the tools used for the weather
prediction, so they are accurate.

Regards,

Isaac OLEG


  • 10.  Humidistat Accuracy

    Posted 12-02-2002 15:15 
    From Ron Nossaman <RNossaman@cox.net>

>I have a big pile of copies of a full-color beautiful Damp-Chaser 
>marketing handout that describes how the use of their dehumidifier system 
>keeps the relative humidity (RH) of the atmosphere in the area of the 
>piano soundboard at maximum of 42% RH. Why is it that when I place the 
>probe of my NIST-certified 1% accuracy hygrometer on top of my Damp-Chaser 
>humidistat, it reads 55% RH? When I place the probe on top of the 
>soundboard it reads 55%. When I place the probe in the middle of the room 
>where the piano resides, it reads 55%. The heater rods are not warm. The 
>atmosphere next to the soundboard should be 42%. The room and  everywhere 
>else around the piano is 55% RH. The humidistat should turn on 
>at.......something near 42% RH.  I'm looking at the pretty 
>graph:  http://www.dampp-chaser.com/main.html  It suggests that RH won't 
>even come close to 55%. Where is the discrepancy?
>
>Terry Farrell


Pardon me folks, but while you are busy answering a question on using a 
Dampp-Chaser humidistat on a room de-humidifier, wasn't Terry's question 
here about a Dampp-Chaser system correctly installed in his piano? That's 
how it reads to me, and I'd be curious as to why the heater rods aren't on 
at 55% RH too.

Ron N


  • 11.  Humidistat Accuracy

    Posted 12-02-2002 15:56 
    From Ron Nossaman <RNossaman@cox.net>

>It may be in the high end of the switching zone.
>
>55% with a high temperature in the room is the same as 42% with a
>colder one.
>So the only data about RH is not enough for me, as you look (I
>presume) for the stability of the wood.
>
>Regards.
>
>Isaac OLEG

You're absolutely right. A 37?F room at 42%RH has an MC of about 8.23%. So 
does a room of 145?F at 55%RH. It's probably working fine and Terry just 
has his thermostat set 75?F too high. Could happen to anyone.

Ron N


  • 12.  Humidistat Accuracy

    Posted 12-02-2002 16:45 
    From Ron Nossaman <RNossaman@cox.net>

>You're absolutely right. A 37?F room at 42%RH has an MC of about 8.23%. So 
>does a room of 145?F at 55%RH. It's probably working fine and Terry just 
>has his thermostat set 75?F too high.

OK, so it's 108?F.


>Could happen to anyone.

You said it.

Ron N


  • 13.  Humidistat Accuracy

    Posted 12-03-2002 05:39 
    From Ron Nossaman <RNossaman@cox.net>

>I just checked my book
>
>60 % R.H at 73 F? is having the same quantity of water in the air than
>40% R.H. at 59 F?

What book is that? I show:
73? F @ 60% RH = 10.9% MC
59? F @ 40% RH = 7.8% MC



>That was the sense of my remark.

I understood your remark. I just can't verify your figures.



>Is not this water what we try to control ?

I assumed that's what we were talking about here.

Ron N


  • 14.  Humidistat Accuracy

    Posted 12-02-2002 15:30 
    From "Isaac OLEG" <oleg-i@wanadoo.fr>

It may be in the high end of the switching zone.

55% with a high temperature in the room is the same as 42% with a
colder one.

So the only data about RH is not enough for me, as you look (I
presume) for the stability of the wood.

Regards.

Isaac OLEG


> -----Message d'origine-----
> De : pianotech-bounces@ptg.org
> [mailto:pianotech-bounces@ptg.org]De la
> part de Ron Nossaman
> Envoye : lundi 2 decembre 2002 23:15
> A : Pianotech
> Objet : Re: Humidistat Accuracy
>
>
>
> >I have a big pile of copies of a full-color beautiful Damp-Chaser
> >marketing handout that describes how the use of their
> dehumidifier system
> >keeps the relative humidity (RH) of the atmosphere in the
> area of the
> >piano soundboard at maximum of 42% RH. Why is it that when
> I place the
> >probe of my NIST-certified 1% accuracy hygrometer on top
> of my Damp-Chaser
> >humidistat, it reads 55% RH? When I place the probe on top of the
> >soundboard it reads 55%. When I place the probe in the
> middle of the room
> >where the piano resides, it reads 55%. The heater rods are
> not warm. The
> >atmosphere next to the soundboard should be 42%. The room
> and  everywhere
> >else around the piano is 55% RH. The humidistat should turn on
> >at.......something near 42% RH.  I'm looking at the pretty
> >graph:  http://www.dampp-chaser.com/main.html  It suggests
> that RH won't
> >even come close to 55%. Where is the discrepancy?
> >
> >Terry Farrell
>
>
> Pardon me folks, but while you are busy answering a
> question on using a
> Dampp-Chaser humidistat on a room de-humidifier, wasn't
> Terry's question
> here about a Dampp-Chaser system correctly installed in his
> piano? That's
> how it reads to me, and I'd be curious as to why the heater
> rods aren't on
> at 55% RH too.
>
> Ron N
>
> _______________________________________________
> pianotech list info: http://www.ptg.org/mailman/listinfo/pianotech
>


  • 15.  Humidistat Accuracy

    Posted 12-02-2002 19:43 
    From "Farrell" <mfarrel2@tampabay.rr.com>

RH is everything. If something reacts at 42% RH or 55% RH, that is independent of temperature.

Terry Farrell
  

    
                                                
    
					
                                                    

        
                                                
				
    
                                                
    
                                                    
                                                        
                                                        Original Message


  • 16.  Humidistat Accuracy

    Registered Piano Technician
    Posted 12-02-2002 16:17 
    From Don <pianotuna@accesscomm.ca>

Hi Ron,

Terry took the thread to his room dehumidifier, not I.

At 04:15 PM 12/2/02 -0600, you wrote:
>
>>I have a big pile of copies of a full-color beautiful Damp-Chaser 
>>marketing handout that describes how the use of their dehumidifier system 
>>keeps the relative humidity (RH) of the atmosphere in the area of the 
>>piano soundboard at maximum of 42% RH. Why is it that when I place the 
>>probe of my NIST-certified 1% accuracy hygrometer on top of my Damp-Chaser 
>>humidistat, it reads 55% RH? When I place the probe on top of the 
>>soundboard it reads 55%. When I place the probe in the middle of the room 
>>where the piano resides, it reads 55%. The heater rods are not warm. The 
>>atmosphere next to the soundboard should be 42%. The room and  everywhere 
>>else around the piano is 55% RH. The humidistat should turn on 
>>at.......something near 42% RH.  I'm looking at the pretty 
>>graph:  http://www.dampp-chaser.com/main.html  It suggests that RH won't 
>>even come close to 55%. Where is the discrepancy?
>>
>>Terry Farrell
>
>
>Pardon me folks, but while you are busy answering a question on using a 
>Dampp-Chaser humidistat on a room de-humidifier, wasn't Terry's question 
>here about a Dampp-Chaser system correctly installed in his piano? That's 
>how it reads to me, and I'd be curious as to why the heater rods aren't on 
>at 55% RH too.
>
>Ron N
>
>_______________________________________________
>pianotech list info: http://www.ptg.org/mailman/listinfo/pianotech
>
>

Regards,
Don Rose, B.Mus., A.M.U.S., A.MUS., R.M.T., R.P.T. Tuner for the Center of
the Arts

mailto:pianotuna@accesscomm.ca

http://us.geocities.com/drpt1948/

3004 Grant Rd.
REGINA, SK
S4S 5G7
306-352-3620 or 1-888-29t-uner


  • 17.  Humidistat Accuracy

    Registered Piano Technician
    Posted 12-02-2002 16:22 
    From Don <pianotuna@accesscomm.ca>

Hi Terry,

Please give us a bit more information. I think you have a Boston Piano?
Grand? Upright? Bottom Cover (or back cover)? How many dehumidifier rods?
How far from soundboard is Humidistat? How far is hum from humidifier? How
far is hum from drier bar(s)? Three light kind? Smart Bar? How long did you
leave your probe on top of the humidistat? Did you chart against barometric
pressure for a true R.H. reading?

At 04:15 PM 12/2/02 -0600, you wrote:
>
>>I have a big pile of copies of a full-color beautiful Damp-Chaser 
>>marketing handout that describes how the use of their dehumidifier system 
>>keeps the relative humidity (RH) of the atmosphere in the area of the 
>>piano soundboard at maximum of 42% RH. Why is it that when I place the 
>>probe of my NIST-certified 1% accuracy hygrometer on top of my Damp-Chaser 
>>humidistat, it reads 55% RH? When I place the probe on top of the 
>>soundboard it reads 55%. When I place the probe in the middle of the room 
>>where the piano resides, it reads 55%. The heater rods are not warm. The 
>>atmosphere next to the soundboard should be 42%. The room and  everywhere 
>>else around the piano is 55% RH. The humidistat should turn on 
>>at.......something near 42% RH.  I'm looking at the pretty 
>>graph:  http://www.dampp-chaser.com/main.html  It suggests that RH won't 
>>even come close to 55%. Where is the discrepancy?
>>
>>Terry Farrell


Regards,
Don Rose, B.Mus., A.M.U.S., A.MUS., R.M.T., R.P.T. Tuner for the Center of
the Arts

mailto:pianotuna@accesscomm.ca

http://us.geocities.com/drpt1948/

3004 Grant Rd.
REGINA, SK
S4S 5G7
306-352-3620 or 1-888-29t-uner


  • 18.  Humidistat Accuracy

    Posted 12-02-2002 19:40 
    From "Farrell" <mfarrel2@tampabay.rr.com>

Boston GP-178 grand. No bottom cover. Six rods totalling 195 watts. Top of humidistat is 2" below soundboard panel. No humidifier (room never gets below 40% RH. No light kind. Left probe on humidistat for 20 minutes or so - plenty of time for full equalization No, I am not aware of barometric pressure influence on RH.

Checked RH this evening. Right at 58% RH. Rods stone cold.

Terry Farrell
  

    
                                                
    
					
                                                    

        
                                                
				
    
                                                
    
                                                    
                                                        
                                                        Original Message


  • 19.  Humidistat Accuracy

    Registered Piano Technician
    Posted 12-02-2002 20:15 
    From Don <pianotuna@accesscomm.ca>

Hi Terry,

D.C. does suggest that the humidistat be placed as close to the sound board
as possible. I don't ever run into a situation where I do a "rods only"
install, so obviously I have little expertise in that area. In my regular
full system installs I tend to get the controller within 1/4 inch of the
sound board (or closer if I can). I would tend to use a bottom cover in
your situation however, and drop the number of rods down.

Terry how far from the controller to the "nearest" rod?

Long shots follow:

1. I hate to say it--but....is it plugged in the "right way"? *grin*.

2. Is it possible that the controller you are using was once used to
control the room dehumidifier you mentioned? It's possible it is damaged. 

At 09:40 PM 12/2/02 -0500, you wrote:
>Boston GP-178 grand. No bottom cover. Six rods totalling 195 watts. Top of
humidistat is 2" below soundboard panel. No humidifier (room never gets
below 40% RH. No light kind. Left probe on humidistat for 20 minutes or so
- plenty of time for full equalization No, I am not aware of barometric
pressure influence on RH.
>
>Checked RH this evening. Right at 58% RH. Rods stone cold.
>
>Terry Farrell
>  
>
    
                                                
    
					
                                                    

        
                                                
				
    
                                                
    
                                                    
                                                        
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  • 20.  Humidistat Accuracy

    Posted 12-03-2002 06:20 
    From "Farrell" <mfarrel2@tampabay.rr.com>

Bottom covers were not around when I did the install several years ago. Perhaps I will do that sometime - I like the idea of them.

I seem to recall that when installing the humidistat, access with a drill pushed the unit 2 inches from the board. This still would not affect why it doesn't seem to turn on at 58%. Oh, and BTW, it is a "DRY" humidistat - I believe it is supposed to keep the environment around 38% or so. I always use the "DRY" (or is it the "WET" one? - anyway, the one that targets the drier RH - it's been a couple years since I last ordered a humidistat) version because it at least seems to get me a little closer to target.

Hey, you never know, but yes, the rods are plugged into the correct spot.

I'm sure the humidistat was not used with the dehumidifier. I did use a humidistat on my old dehumidifier because the built-in humidistat was so erratic. My new dehumidifier has a very good humidistat - I keep it set to 45% and the shop stays right between 43% and 44%. So I don't use the DC humidistat for that purpose any more.

If I were using a full system, whether the piano stayed at 42%, 38% 58% or even 68%, I don't think it would make a whole lot of difference (or would we tend to get a bit of string corrosion at 68%?). But because, in a modern air-conditioned Florida home, RH rarely gets above 75%, nor below 40%, it give us the opportunity down here to not use the humidifier part of the DC system, and still maintain a stable optimal environment. Any time you can bypass something that requires maintenance, puts water in a piano, causes lights to flash, costs more money, bla, bla, bla, - AND get the same benefits - you come out way ahead. That is why I want my dehumidification system on my pianos down here to create a piano environment of around 40% to 45% - when the home does go to its extreme 35% or 40% RH in the dead of winter, we still won't see much change in the piano environment. So, for our Florida environment having a dehumidification system that keeps the piano RH down in the lower 40%s is where we want to be. That is why I keep getting frustrated with something that appears to keep the piano closer to 60% RH.

Terry Farrell
  

    
                                                
    
					
                                                    

        
                                                
				
    
                                                
    
                                                    
                                                        
                                                        Original Message


  • 21.  Humidistat Accuracy

    Posted 12-03-2002 08:54 
    From "Roger Wheelock" <roger@dampp-chaser.com>

Hi Terry,

Here's a note from Bob Mair.  He does not subscribe to the list so I am
posting for him.

Roger

Terry,

Send it (the Humidistat) back.  Let's put it through the test program.
Let's settle what the calibration is rather than continuing to speculate.
We will send you a replacement to use while the one in question is being
sent back.

Bob


> So, for our Florida environment having a dehumidification system that
keeps the piano RH down in the lower 40%!
> s is where we want to be. That is why I keep getting frustrated with
something that appears to keep the piano closer to 60% RH.
>
> Terry Farrell


  • 22.  Humidistat Accuracy

    Posted 12-03-2002 09:35 
    From Ron Nossaman <RNossaman@cox.net>

>Here's a note from Bob Mair.  He does not subscribe to the list so I am
>posting for him.
>
>Roger

Roger,
If I've been told, I've forgotten. What would be a reasonable expected 
average cycle time for a humidistat with a full system in a stabile 
environment.

Ron N


  • 23.  Humidistat Accuracy

    Posted 12-03-2002 09:59 
    From "Roger Wheelock" <roger@dampp-chaser.com>

Hi Ron,

In a grand with an H-3 Humidistat positioned 4 to 6 inches from the
Humidifier we see a 3-4 hour cycle.  The Dehumidifier is energized about 1/3
of the time.

Adding an undercover and positioning the H-3 at 12 to 14 inches from the
Humidifier results in a cycle time as short as an hour.  We believe this is
a reflection of the system working in a more confined space.

It is our opinion that a shorter and more regular cycle allows for more
effective stabilization of soundboard moisture content.

Thanks,

Roger


    
                                                
    
					
                                                    

        
                                                
				
    
                                                
    
                                                    
                                                        
                                                        Original Message


  • 24.  Humidistat Accuracy

    Posted 12-03-2002 10:15 
    From Ron Nossaman <RNossaman@cox.net>

>In a grand with an H-3 Humidistat positioned 4 to 6 inches from the
>Humidifier we see a 3-4 hour cycle.  The Dehumidifier is energized about 1/3
>of the time.
>
>Adding an undercover and positioning the H-3 at 12 to 14 inches from the
>Humidifier results in a cycle time as short as an hour.  We believe this is
>a reflection of the system working in a more confined space.

Hi Roger,
Makes sense, steeper change gradients.


>It is our opinion that a shorter and more regular cycle allows for more
>effective stabilization of soundboard moisture content.

Makes sense to me too.

Thanks,

Ron N


  • 25.  Humidistat Accuracy

    Registered Piano Technician
    Posted 12-03-2002 07:44 
    From Don <pianotuna@accesscomm.ca>

Hi Terry,

Don't bother to drill *grin*.

At 08:20 AM 12/3/02 -0500, you wrote:
>Bottom covers were not around when I did the install several years ago.
Perhaps I will do that sometime - I like the idea of them.
>
>I seem to recall that when installing the humidistat, access with a drill
pushed the unit 2 inches from the board. 

Regards,
Don Rose, B.Mus., A.M.U.S., A.MUS., R.M.T., R.P.T. Tuner for the Center of
the Arts

mailto:pianotuna@accesscomm.ca

http://us.geocities.com/drpt1948/

3004 Grant Rd.
REGINA, SK
S4S 5G7
306-352-3620 or 1-888-29t-uner


  • 26.  Humidistat Accuracy

    Posted 12-03-2002 03:02 
    From "Isaac OLEG" <oleg-i@wanadoo.fr>

Ron, your are certainly right too !

But is not the real weight of the water in the air the final factor we
should consider ? (as being able to affect piano parts)?

In this case, R.H is only an indication, that was the idea of my
(exaggerated) post.

Anyway, as I understand it, the warmer the air, the most water he is
able to accept before saturation, so for example when people open the
windows in winter believing they will add some moisture inside, in
fact they do not because the cold air outside is may be showing more
H.R, because nearer of saturation, when it goes in the warm room, the
quantity of water it contents is in fact less in proportion to the
saturation point (R.H.).

The same apply to the humidistat, so I say that H.R. values is not
sufficient, or we may say that we accept a range of H.R. and a range
of temperature together.
If my room is a bit warm and I read 50% RH it is fairly possible that
when colder there will not be as much R.H showed by my hygrometer, as
I understand it anyway, it is useless to maintain the same H.R all
along the year, or the temperature should be maintained too.

I have no idea of the amount of changes of the air pressure when at
ground level, but they play a role in the numbers that the hygrometers
give us too (and the way humidistat react.

It is not to say that the DC humidistat are precision devices, but I
guess that they are playing they role generally well (I hope so
anyway)
What I should be more concerned is of their use in the high humidity
ranges, as the rods may not be able to warm enough air to absorb
enough the moisture.
Then we obtain warm moist air, and that can be prejudicial to the
instrument.

In France the piano trade tend to consider high R.H as being good for
the pianos (i.e.) 50%-60%.

As these agree parameters easily encountered in homes this is a good
argument for selling pianos (and a bad one to sell Damp Chaser
systems) It may be an old habit from the iron strings, and wooden
frames.

Probably clear as mud, any clearing will be appreciated.


regards.

Isaac OLEG




> -----Message d'origine-----
> De : Ron Nossaman [mailto:RNossaman@cox.net]
> Envoy? : lundi 2 d?cembre 2002 23:56
> ? : oleg-i@wanadoo.fr; Pianotech
> Objet : RE: Humidistat Accuracy
>
>
>
> >It may be in the high end of the switching zone.
> >
> >55% with a high temperature in the room is the same as 42% with a
> >colder one.
> >So the only data about RH is not enough for me, as you look (I
> >presume) for the stability of the wood.
> >
> >Regards.
> >
> >Isaac OLEG
>
> You're absolutely right. A 37?F room at 42%RH has an MC of
> about 8.23%. So
> does a room of 145?F at 55%RH. It's probably working fine
> and Terry just
> has his thermostat set 75?F too high. Could happen to anyone.
>
> Ron N
>
>


  • 27.  Humidistat Accuracy

    Posted 12-03-2002 04:33 
    From "Isaac OLEG" <oleg-i@wanadoo.fr>

>
> RH is everything. If something reacts at 42% RH or 55% RH,
> that is independent of temperature.
>
> Terry Farrell

Sure it is supposed to, but it is possible that depending of the
capacitances used some probe are more sensible than others.

What I have seen is that the hygrometers are reacting the same at 5%
diff when in "normal conditions", but their readings differ way more
in dry or humid ones, or in very warm or very cold situation.

Isaac OLEG

Ventilation of the place where the humidity is read play a role too.


  • 28.  Humidistat Accuracy

    Posted 12-03-2002 04:59 
    From "Isaac OLEG" <oleg-i@wanadoo.fr>

I just checked my book

60 % R.H at 73 F? is having the same quantity of water in the air than
40% R.H. at 59 F?


That was the sense of my remark.

Is not this water what we try to control ?


Regards.

Isaac OLEG

> -----Message d'origine-----
> De : pianotech-bounces@ptg.org
> [mailto:pianotech-bounces@ptg.org]De la
> part de Ron Nossaman
> Envoy? : mardi 3 d?cembre 2002 00:45
> ? : Pianotech
> Objet : RE: Humidistat Accuracy
>
>
>
> >You're absolutely right. A 37?F room at 42%RH has an MC of
> about 8.23%. So
> >does a room of 145?F at 55%RH. It's probably working fine
> and Terry just
> >has his thermostat set 75?F too high.
>
> OK, so it's 108?F.
>
>
> >Could happen to anyone.
>
> You said it.
>
> Ron N
>
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>