Polutants and Polymer sensors
 

Last year I bought 5 dehumidifiers. As I put each to use, they eventually
failed. The failure was the readout value and functionality of the
humidistat in all but one unit which simply rattled too much. Something had
to be wrong with the environment, right? Well, this year, using a soap
solution, I found four slow gas leaks, all of which I then fixed. I bought
another Dehumidifier (a GE unit). Knock-on-wood this dehumidifier has not
failed. However, from the start the GE's readout shows 35% when the wet-
bulb hydrometer calculates as 65% and my digital hydrometer reads 65%.

I think the Natural gas was a source of pollution that permeated the
humidity sensors polymer substrate in each dehumidifier.

A search yielded this text:


Chemical vapors may interfere with materials used for the humidity sensor.
The diffusion of chemicals into the sensor's polymer may cause a shift in
both offset and sensitivity. In a clean environment the contaminants will
slowly dissipate. The reconditioning procedure will accelerate this
process. High levels of pollutants may cause permanent damage to the
humidity sensor's polymer.

Any comments?


Dave M.