Bobby_M wrote:
Joseph,

Actually I think the older model 600's did not have the probe. I think
it was a design enhancement recently. Then again, I could easily see
an installer skipping it because it technically still humidifies and
shaves off a few minutes of his labor.

Bobby

You may well be right, I really don't know, but their description on
their web site sounds like it has always been there although it does not
clearly say so.

"The Aprilaire Automatic Humidifier Model 600 is the newest addition to the
aprilaire humidifier line. It takes humidifier innovation to the next level
and performs as good as it looks! It offers all of the performance benefits
of Aprilaire's more advanced humidifiers including AutoTrack which
automatically adjusts humidity based on outside temperature. "


--
Joseph Meehan

26 + 6 = 1 It's Irish Math