[CAUT] HVAC information - Data Loggers

[Roger Wheelock]

Hello Don and List,

While I would be the first to say these data loggers are certainly 
affordable and easy to use, their accuracy can be highly variable.  We have 
found that manufactures of data loggers often "inflate" their relative 
humidity accuracy specification and do not discuss instrument drift with 
time.

It seems fairly ironic having an instrument that reads to 0.1% RH when the 
accuracy specification is +/- 3% (Model TW-USB-2) or +/- 4.5% (Model 
TW-USB-RT).  We recommend investing in a data logger that has +/- 2% 
accuracy or better, and then have it calibrated annually.  This Dickson 
model has been a workhorse for us over the years. 
http://www.dicksondata.com/product/model_TP125.php

Roger

----- Original Message ----- 
From: "Don Mannino" <DMannino at kawaius.com>
To: <grahampianos at yahoo.com>; <caut at ptg.org>
Sent: Tuesday, January 06, 2009 10:53 AM
Subject: Re: [CAUT] HVAC information - Data Loggers


Perhaps someone has already mentioned this and I missed it, but I have
come across a great tool for diagnosing and illustrating environmental
issues.  It is a relatively inexpensive and small data logger.

http://www.thermoworks.com/products/logger/usb_loggers.html

I like the TW-USB-2, which costs $82 and is quite accurate.

You install a small program with USB drivers in your computer, then plug
in the data logger.  You tell it through the software how often you want
to take measurements, and when to start measuring.  You then take the
data logger out of the computer, and place it in the room you want to
check.  It's only a few inches long, so can be taped under a piano
easily.

After whatever length of time you want recorded, you plug the logger
back into the computer and it makes a very nice graph of the temperature
and humidity levels.  This can be printed.

It seems to me that this kind of a tool would be a great aid in
illustrating how severe the conditions are, and armed with this chart
and some backup materials related to humidity levels and piano
soundboards, you would be better prepared to discuss the need for better
controls in a building.

I attached a PDF of one of the charts, a measurement of the overnight
conditions in our Shigeru Kawai showroom here in California.  You can
just see the temperature and humidity bump up at the very end when I
picked it up and carried it to my office to download the readings in the
morning.

Don Mannino