On Tuesday, November 25, 2014 9:25:35 AM UTC-5, wrote:
On Tuesday, November 25, 2014 7:58:57 AM UTC-5, trader_4 wrote:
On Monday, November 24, 2014 11:46:43 PM UTC-5, micky wrote:
On Mon, 24 Nov 2014 19:28:33 -0800 (PST), Hongyi Kang
wrote:


Thanks Edward, one of the websites Nate posted earlier:
http://home.fuse.net/clymer/water/rh.html=20

actually had the conversion between different temperature's RH. And I just=
finished the salt calibration of my hygrometer, it's actually measuring 70=
% instead of 75%, so I guess it is 5% off. The temperature of the air comi=
ng out of the hot register was between 95 and 102. Based on these, I think=
my humidifier is probably working fine, just not enough yet for my wife's =
problem. I'll ask the service tech and see if they could rewire the unit s=
o that it can run while the blower is on. Thanks!

That' a very good idea. I had a room AC when I lived in a very small
room and the AC was right next to my bed, and the fan ran all night even
if the air had cooled off and the compressor wasn't running. I hated
the noise.

I took off the cover, and just had to rearrange three slip-on
connectors. I didnt' have to cut or solder anything, and when the
compressor went off, the fan did too. Furnaces and humidifiers are
more spread out so it probably won't be that easy, but it can certainly
be done.

Actually you only need one wire with two ends.

There is probably a neutral wire from the humidifier to a common neutral
somewhere . You can leave that alone. All you need is a hot
wire that runs from the hot wire where the blower gets its power and
goes straight to the humidifier, where the hot wire from the furnace
control unit already connects to the humidifier. So the power
doesn't have to go through the furnace control unit.


Are you aware that he said he had a variable speed blower, which
today is likely ECM?

right.

and even with an old fashion multi speed blower there are complications. If you connect the humdifier directly to the blower motor, the humidifer will be fed with different voltages when the blower operates at different speeds.

The best way to deal with this is to add another relay to power the humidifer.

They have current sensing relays that can be added. But he may not even
need one. It's a modern furnace and they typically have outputs on the
control board for a humidifier, air cleaner, etc. First thing is to find
out what the furnace has and under what conditions it's activated.

Plus it looks like a moot point to me. After measuring the humidity in
the house, instead of at the hot air register, I believe the OP reported he
was getting 70 - 75% with the way it's wired now. He said something about
making it higher, but that's another story, and IMO, a bad idea.




Bottom line, use a relay or be sure to connect to a the high speed tap and use a meter to check the voltage at the humidifer over all modes of operation.
Nothing is ever easy. :-)

Mark

Leaving what's working alone is.....