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Can you control indoor humidity with HAI?

Acropolis

Member
Now that I have a better overall understanding of automation systems, I am trying to iron out some of the details for my system. I noticed that HAI has a temp/humidity sensor. Is it possible to tell the system to turn on the humidifier and fan on my furnace without turning on the heat? I currently have a thermostat (stand alone) that allows you to set an upper and lower humidity setting (34% - 39% for example). If the system is set to heat and the indoor humidity level falls below the set level, the thermostat will turn on the fan and humidifier to raise the humidity without turning on the actual flame for the heat (unless the temp falls below setting as well). This maintains the humidity levels without the extra expense of heating unnecessarily.

If it can't be done directly through the HAI thermostat, would it be possible to use some sort of trigger to kick on the humidifier and set the thermostat to fan until the desired humidity level is reached?

Taking it one step further, in the perfect world (automation gets us one step closer) your ideal indoor humidity levels would change based on outdoor temperature. By adding an outdoor temperature sensor, you could easily have the system adjust the desired humidity level base on outdoor temp with no manual interaction.

I am not sure how feasible any of this is, but I am hoping that someone will be able to point me in the right direction.

Thanks,
Acropolis
 

BobS0327

Active Member
You can control the furnace fan using the HAI RC80 thermostat and the HAI humidity sensor. Programmatically, it's done as follows:

Code:
When HumidSensor NOT READY: THERMOSTAT FAN ON
where the sensor goes to a NOT READY state when the sensor reading is not in the accepted humidity range and ONLY turns the fan on.

I'm not aware of any way to control the furnace humidity via HAI programming
 

Madcodger

Active Member
I had a friend who rigged his furnace humidifier to run all the time, as his house was very dry one winter. As I recall, he had two problems: One, their was a large amount of excess water that the humidifier did not use, that was just wasted down the drain. Two, the performance wasn't that great without the benefit of added heat from the furnace.

Now, that said, I'd really like to be able to do this and may just try it, perhaps using some modification to limit the water flow. We have the largest furnace humidifier possible according to our HVAC guy, yet the house is always too dry in the winter and we have to run those annoying room units in the bedrooms.

If anyone has tried this or comes up with good ideas, particularly related to limiting the water flow to avoid waste, please post!
 

Acropolis

Member
Rupp said:
Mad,
  What do you mean by waste?  How is your humidifier designed?
If his humidifier is like mine, water trickles through a screen from a small pipe. any water that is not blown into the air goes down a drain so that there is no standing water for bacteria to grow in. It actually doesn't stay on all the time. There is a small solenoid that is triggered by the humidistat that opens to turn on the water when the fan is blowing and the humidity levels are below the set range. With a traditional thermostat, the heat has to turn on any time the humidity level gets to low (even if the temperature is warm enough). Now that I am talking through this, I am guessing that I coud use the HAI system to open and close the solenoid when it turns on the fan (and the humidity is below the set level). I just need to learn more about the HAI system and if it can open and close a low voltage solenoid using a trigger of some kind (I'm guessing it's actually the same type of control as the fan itself).

Actually, my current thermostat will turn on the humidifier without the heat when needed. It is great because I am not paying for gas when the house is warm enough, but needs more humidity.

Hmmm.... I'm starting to think that this system is going to have me automating a lot of things (and I haven't even ordered it yet).
 

Madcodger

Active Member
Rupp said:
Mad,
What do you mean by waste? How is your humidifier designed?
Rupp,

Acropolis is correct. Any water not used goes down the drain. From what I've seen on my system and my friend's, it's quite a bit.

One problem I have is that I keep the fan running on our furnace 24/7. I thought our HVAC contractor was nuts when he suggested it, but with a variable speed fan it really helps to control dust in a house. The fan runs on low and is constantly filtering the air, which is great. When it needs to run at a higher speed to produce heat, it speeds up automatically.

I may be able to tie into the output that turns on the higher fan speed...
 

Acropolis

Member
Madcodger,

You should be able to turn down the water so that it is only a drip through the filter. If you are hearing water running down the drain, you have it way to high. It should just be a drip to keep the pad wet.

You could also look at something like what I am doing to only open the water solenoid when the humidity levels are low or only when the fan is on high. Have you measured the indoor humidity levels?

Acropolis
 
I've got a Skuttle 45 on my heater (installed by previous owner). I have no drain capability so I'm trying to tune it to keep the min amount of water in the pan as possible.

I was was going to hook up the motor to a powerflash (or Insteon equivalent) then control the fan with my Indigo set up. Still need humidity sensing capabilities though.
 

Madcodger

Active Member
Acropolis said:
Madcodger,

You should be able to turn down the water so that it is only a drip through the filter. If you are hearing water running down the drain, you have it way to high. It should just be a drip to keep the pad wet.

You could also look at something like what I am doing to only open the water solenoid when the humidity levels are low or only when the fan is on high. Have you measured the indoor humidity levels?

Acropolis
Thanks, Acropolis. I think you're absolutely right - I had it too high, as did my friend. I haven't measured indoor humidity through the HA system yet. I use HomeSeer, and have been hoping the ACRF plugin for that would be able to handle the Oregon Scientific sensors as I have several that report into a freestanding RF monitor / receiver. It won't tie into the HA system, though.

If I can ever get a few days off, this is one of the projects I want to play with.

Joe
 
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