[pianotech] Protection from underfloor heating

[Jim Ialeggio]

Joseph wrote:

<I was indeed referring to the "mid-summer" compared to "mid-winter" 
differential

I'd like to try and get a better sense of what is, could be or isn't 
happening with these system regarding pianos and piano stability. I'm 
curious whether the reports of piano instability caused by in floor 
systems are caused by the unfamiliarity effect, or whether the reports 
are a real effect. This means I'd like to compare any apparent 
detrimental effects in a fair comparison with other heating systems.

In reading posts on this subject over a number of years, a warning sign 
goes off instantly in my head. It's the "unfamiliar-thus-suspect" 
warning sign. According to the negative reports on in-floor heating, one 
might infer that other heating systems do not present stability issues 
to pianos. With the exception of wood stoves, traditional heating is 
never directly fingered as a threat to piano stability, but rather in 
traditionally heated buildings, the occupants are not maintaining 
appropriate interior conditions for piano stability. In-floor heating, 
on the other hand is fingered directly as the culprit, rather than the 
home system or the occupants responsibility to maintain appropriate 
ambient climate.

Is this a bias favoring the familiar or is it a reasonable bias?

I find a striking disconnect between technician reports on the 
aggressiveness of infloor heat regarding piano seasonal stability and 
piano soundboard/pinlock health, and both the technical research and on 
site installed experience gathered by the heating industry professionals 
and researchers on these systems. Over the last 20 yrs the in-floor 
systems have exhibited significant advantages over traditional systems.  
In-floor systems have proven to be more comfortable, gentle, and 
allergen friendly than any of the traditional heating options, providing 
even temperatures, much less vertical temp striation, and allowing the 
occupied spaces to be kept at lower temperatures(thus easier to maintain 
higher RH) than their convective/forced counterparts. 
http://legalett.ca/Radiant_Floor_Heating_in_Theory_and_Practice.pdf

So Joseph, as a starting place, and others please contribute as well, 
could you specify what you find when you show up to tune pianos in these 
homes after the heat kicks in or shuts down for the season...in terms of 
sharp/flat cents swings, unison disintegration, pin block behavior, 
soundboard compression ridges/splits, etc. Others who have not 
experienced stability swings also please make yourselves known. Lets 
hold off on any conclusions, but try to specify what symptoms, positive 
or negative we techs are specifically finding when they approach a piano 
in a in floor heated space.

In the spirit of taking the information where it takes us, I'll start, 
with my own experience.

My own grand, Chickering122, 5' grand, my own new re-manufacture (new 
rib crowned board, block, the works), full DC, floor length cover always 
covering instrument when I'm not playing, in my living room with 
in-floor heat.

Last tuned june 2012.  Using an ETD...Stoppers Only Pure...which I used 
when I tuned it in June, the cents offsets from where I put it in June 
are A2 (-)3cents, A3 (-)0.6cents, A4 (+)0.4 cents, A5 (+)2.2 cents, A6 
(-)1cent, A7 (-)9 cents   A1 is (-) 12 cents, from the program, but I 
don't agree with the ETDs on wound strings, so my stretches in the bass 
(A1, A2) are not Stopper's. I will quantify where I put these in the 
future for further reference. Piano needs a tuning (which I've been too 
busy to get to), as unisons have strayed unacceptably for my very picky 
ear. No wild unisons, but more movement than I find acceptable, and 
accomanying increased harshness in the treble. I did notice that the 
unisons strayed more noticeably as the heat kicked in full time. Initial 
RH of the house drops over the course of 2 weeks or so as the heat kicks 
in.

Current RH December 13, 1 new pocket meter says 49% @ 63f.  An older 
digital says 51% @ 67f.


Jim Ialeggio

-- 
Jim Ialeggio	
jim at grandpianosolutions.com
978 425-9026
Shirley Center, MA