On Oct 8, 2:47*am, "Lefty" wrote:
"Jim Elbrecht" wrote in message
...
On Wed, 7 Oct 2009 18:13:36 -0400, "RBM" wrote:
"Jim Elbrecht" wrote in message
-snip-
Could someone look at these and try to put into words where the
transformer wires-- 2 black & a green-- go?
Schematic
http://i289.photobucket.com/albums/l...ng_diagram.jpg
Humidifier hook-up
http://i289.photobucket.com/albums/l...ifierwiring_sm....
If you want the transformer to power up when the blower is on, connect it
to
the white and black wires where the diagram shows the blower, unless
you're
using the medium speed, then use the white and blue
Thanks-- * I didn't think that was a choice *I* made. * *I thought the
furnace chose the speed & I was looking for something to connect to
before it made that choice. * *I'll have another read through the
literature to see what it says about the two speeds.
Thanks-
Jim
You *are* using the medium speed (the blue wire). *The black wire is from
the air conditioning relay. *The blue wire is from the fan/limit control,
which is connected to the heating speed tap at (or near) the blower motor.. I
don't see where this furnace can choose it's own speed, based on the
provided diagram. *The tech who sets this furnace up will measure the
temperature rise (heating) and drop across the evaporator (cooling) and
physically plug in the black and blue wires into the speed tap accordingly.
On looking at this again, I agree with your analysis. It appears the
blue wire is used to power the fan for heating and the relay selects
black when in AC mode. So, he would have 120V between the blue and
white fan wires during heating.
Anyway, the huimidifier is automatically interlocked to only run on a
heating fan call, not during a cooling nor fan on (at thermostat subbase)
call.
Assuming of course that he has it wired up that way. That is how my
Aprilaire is hooked up. It has 120V all the time and has a 24V
trigger lead connected to the furnace controls.
Alternately, you could use the model #50 current sensing relay for
interlock.
HTH, Lefty