View Full Version : Humidifier Fan Blowing Wrong Way?
02-23-2007, 09:44 AM
I've posted here about humidity (lack thereof) problems. Won't go above 22% when it is cold outside.
After trying lots of things, found out that smoke from a blown out candle will not enter the vents to my fan powered humidifier (Carrier).
I opened it up, and it sure looks like the fan is blowing air OUT instead of into the cold air return duct.
I had to installed at the same time along with 2 new furnaces, and I think both are blowing air out.
Is this possible? How to correct?
02-23-2007, 02:15 PM
Fan powered humidifiers pull air from the duct system & then back out into the duct system. They are much less effective in the return side due to lower air temperatures. Effectiveness can also be affected by run times of furnace. In really cold weather, you may not want too much more humidity than you are getting. However, you could get more if the fan type humidifier were located in the supply duct & furnace runtime increases. A steam type humidifier costs more to operate, but will give you the humidity you want, independent of what the temperature of the air inside the duct, as long as the fan is running.
02-23-2007, 02:56 PM
This Carrier humidifier appears to pull area from the surrounding room through vents, across the media, and into the cold air return duct right before the furnace.
However, the fan appears to be running the wrong way. It is pulling air out of the cold air return, across the media, and into the surrounding room.
02-23-2007, 03:42 PM
I have learned from experience to never say never; so have your installing dealer check & verify to you that the humidifier is working as normal. Do not expect much from the return type installation.
02-23-2007, 05:12 PM
Okay, I was wrong about the way the humidifier works. It does not draw air in from the room, but draws it in from the cold air return, across the media, and then BACK INTO THE COLD ERROR RETURN.
Bottom line, I cannot get humidity about 21-22%.
How important is it to have the humidifier installed on the hot air side?
Also, the humidifier only runs when the furnace is burning. Is it sound to run it whenever the fan is blowing (and needs humidity)?
We keep the thermastat at 68, so the furnace does not run a lot.
I have infinity furnace with infinity control. How do I hook it up to run humidifier whenever the fan is running, and the humidity is too low?
02-23-2007, 05:42 PM
Is the humidifier on a horizontal or vertical duct?
As to making it work differently, the best advice I can give you is call the installer. If the system is new he should do this for you for no charge.
As to humidity level, that may be the best it will ever be depending on your house and enviornment....in other words there may be nothing wrong with the humidifer. You may be loosing more moisture due to infiltration than the humidfier is capable of replacing. You may have to go to a steam type humidifier or depending on your house even this may not do it.
02-23-2007, 06:21 PM
A fan powered humidifier installed on the return side of a furnace is not going to be great at increasing the RH in the home. Its hard to evaporate much water with 68 degree air. Even with the fan running, the return air will not be any warmer. The output of those humidifiers are rated with air temperatures of 120 degrees or more. I have been involved in situations like yours; the solution was either put the humidifier in the supply duct, or go to steam humidifiers. If your home has an infiltration problem that leads to low RH in the home; the humidifier in the return duct offers very little help in overcoming the problem.
Powered by vBulletin® Version 4.2.0 Copyright © 2013 vBulletin Solutions, Inc. All rights reserved.