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-   -   Honeywell IAQ thermostat and humidity control (http://www.diychatroom.com/f17/honeywell-iaq-thermostat-humidity-control-33672/)

GhostBuster 12-13-2008 10:50 AM

Honeywell IAQ thermostat and humidity control
 
I have successfully installed my honeywell iaq THM5421C1008 thermostat.
I have a question about the humidity control. The humidity screen shows a 32% humidity reading on the upper left but the unit is apparently calling for 50% humidity located on the lower right. Why is it not able to get the humidity up to 50%? I have place the control on the setting of control of the fan is run by the need for humidity but the unit just dose not seem to turn on the humidifier enought. I have gone into test mode and the thermostat does turn on the humidifier. I have a recently installed desert spring drum humidifier that is supposed to do a house of 3000 square feet and my house id 2000 square feet. I gave it a few week to get the humidity level up. I have an outdoor temp sensor which is accurately working.

beenthere 12-13-2008 12:48 PM

Because your furnace isn't cycling enough.

That model requires the furnace to be running for heat, in order to add humidity(or enough to notice).

Wrong humidifier for your application.

GhostBuster 12-13-2008 03:21 PM

I set the thermostat to the mode where the fan runs when humidity is called for. That did not seem to be enough. What is the right humidifier for my application. This one uses far less water than other models.

beenthere 12-13-2008 03:51 PM

A flow through.
Hooked to the hot water line.
They use more water, but will add moisture to the air.

The only humidifiers that will save water, and add moisture to the air without the furnace running for heat, are steamers.

GhostBuster 12-13-2008 04:38 PM

What is a good brand of steamer. I know honeywell makes one. The Desert is a bypass unit. Is that the same as a flowthrough?

GhostBuster 12-13-2008 04:40 PM

Maybe I could hook my desert spring to the hot water. The hot is softened. Desert Spring recommended un-softened water.

beenthere 12-13-2008 05:20 PM

Hoineywell has the Truesteam. But, the large unit, isn't really able to add that much moisture(12 gallons per day).
I prefer the EWC Autoflo steamer.
The small one is 16 gallons per day, and the large one is 22.

Hot water won't help the desert, it is a sump humidifier. So the water will cool down.

Flow through, is when fresh water is constantly flowing through it.

GhostBuster 12-13-2008 05:43 PM

so flow through is like my old aprilaire at my last house?

beenthere 12-13-2008 06:37 PM

If it was a 500, 600, or 700 model, yes.

SKIP4661 12-13-2008 07:17 PM

Is the outdoor temp sensor integrated with your humidifier? If it is it may be holding your humidity down, especially if your outdoor temp is low. Too much humidity and your windows will sweat. Around here if you have 50% humidity this time of year you won't see out of your windows.

chris75 12-13-2008 08:32 PM

Skuttle makes a good steam humidifier, but alot of maintenance comes with it, I use a Honeywell Flow-Through humidifier with a Invensys T-stat with Humidity sensing to turn the unit on and off, also have the outdoor sensor for the t-stat as well, and it works great.

integlikewhoa 12-18-2008 12:59 PM

Quote:

Originally Posted by SKIP4661 (Post 197599)
Is the outdoor temp sensor integrated with your humidifier? If it is it may be holding your humidity down, especially if your outdoor temp is low. Too much humidity and your windows will sweat. Around here if you have 50% humidity this time of year you won't see out of your windows.

Yes, The outdoor temp is integrated into the whole system.
This is correct. It wont raise the humidity to much inside if the outside temp is very low. It will steam the windows up. I have a zoned IAQ system with a truesteam setup.

GhostBuster 12-18-2008 05:16 PM

Yeah, I looked up the charts that recommend what % humidity for the outdoor temps and my IAQ seemed to be tracking OK. I wonder why my thermostat has a 50% humidity in the lower right corner when it maintains 30 or 32% which matches the tables.

integlikewhoa 12-18-2008 06:52 PM

I don't know about yours but is this on the main screen more screen? Mine shows outside temp on the bottom right.
Well I'm sure it could be a setting option.

GhostBuster 12-19-2008 01:28 AM

it is on the more pressed twice screen where it reports the humidity.


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