On 10/23/2011 11:29 AM, Nate Nagel wrote:
....

... (I could get rid of the sail switch and separate transformer if I
did it that way, too...)

Assuming you replaced it w/ an appropriate humidstat, yes.

....

... does not lock out the humidifier when the A/C
is on which is the main reason why I'm trying to redo it.
....

Nothing but a comparative story follows, but--

Just discovered during a new furnace installation here the humidifier
had been wired that way for 30+ yrs. (I hadn't used it since we moved
back after dad died owing to a leak in the line and thinking were going
to replace anyway, never got the necessary round tuit until this year...)

I suppose Dad simply closed the supply valve in summer. BTW, old units
are not at all unlikely to not have the extra terminals on the control
and the 120V sail switch was also pretty much the standard back then;
same setup here. Also, the humidstat portion had failed so ended up
replacing it and solenoid w/ the low voltage ones and the new furnace
(Carrier) being new does have the terminal so all is well...

--