Art Todesco wrote:
bud-- wrote:
Jim Elbrecht wrote:
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...rwiring_sm.jpg


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

Relay "relay" is connected to thermostat G-C and is energized when the
stat calls for cooling or the stat is set for "fan on". The fan runs
at high speed.

Control "fan & limit switch" is a plenum switch that is operated by
heat. The fan (NO contacts) comes on when the switch gets hot and the
fan is held on while the plenum is hot. The normally closed contacts
only open if the control gets too hot. If the NC contacts open nothing
operates except the fan. "Aux limit" is a redundant safety control.

(Not obvious what the low voltage connection to the "fan & limit
switch" is - "if used". It is connected thermostat W-C and would be
energized when the stat calls for heat. "Relay" has common symbol for
a coil. "Fan & limit switch" is different - probably heat activated.)

The "blue" wire from the "fan and limit switch" terminal "F" to the
"relay" terminal "4" is only on when you are heating. _It is the wire
to tap_.

This is similar to what Lefty said, but you don't want to connect to
the blue wire at the motor.

It is desirable to only power the dehumidifier during heating (not
cooling). The wire above will do that. The other thing to avoid is
connecting (directly or indirectly) to a motor wire that can feed the
wrong voltage to the humidifier solenoid. The wire above also avoids
that.

It is much easier to figure out what is happening with a control
diagram with wiring on horizontal rungs, rather than a connection
diagram provided.

In my old house I used a special gadget where you clamp it around the
neutral wire for the blower. It has 2 leads which you wire in series with
the 24 volt circuit to the humidifier. Here's a link:
http://www.amazon.com/gp/product/B001TXE0G2

Probably what Lefty described.

Worked perfectly. As for not wanting the humidifier to turn on in the
summer, the humidistat will usually take care of that .... you can just
turn
is as low as possible and it'll be ok.


Also, you really don't want to
connect
the 110 volt side of a 24 volt transformer to a multi-speed blower, where
speeds are determined by heating or cooling because strange voltages
appear on the unused lead, i.e. blower running on medium, high lead may
have 160 volts on it depending on the motor.

That was one of my points, and it doesn't happen if connection is made
where I said.

--
bud--