De-humidistat/exhaust fans- who is using them?

benihana

New member
I am in the final stages before Sheetrock goes up, the exhaust fan (pans 110CFM) is installed, but I racking my brain on how to hook up a de-humidistat to it so that I can have it auto controlled

Who is currently using them, and do you have any reccomendations on how to wire them?


Thanks
 
I have installed 2 of them for friends. Pretty straight forward, similar to wiring up a thermostat to control a heater or chiller. You wire the the fan to the humidistat, and the humidistat to an electrical source. Make sure the humidistat is not in close proximity to the fan in the room, else the readings will be affected by the air movement of the fan.

Dave B
 
Uhm, if you do that, make sure it's a line voltage humidistat. Most of the ones I've ever installed are low voltage that control a relay - 24V not 120V
Can't say as I've ever seen a line voltage humidistat, but my experience is in residential HVAC, I'd imagine hydroponic stuff might have line voltage stuff.
 
I asked a similar question a few months ago and came to the conclusion the a HRV was the way to go
 
To wire the Amazon Humidistat - the wiring configuration is printed on the back next to the wire terminals. You could mount it in the box you posted a link to. Or you could buy a plastic junction box at Home Depot or Lowes and mount it in that.

Don't let this task overwhelm you. This is a pretty easy. You are only working with 2 wires (110v AC) so you don't have to worry about + or - leads.

For the one linked to on Amazon you will need the Humidistat and an inexpensive 2 prong extension cord. You will cut the female end off the extension cord. One strand from the extension cord you will add an extra piece of wire to - So you have 2 ends, One end is inserted into socket 3 of the Humidistat. The other end of the first split goes to the First wire from your fan. Now you add another piece of wire to the second wire of the extension cord. One end goes into socket 4 on the humidistat.- Now you have the power connections connected to power up the humidistat. The second pigtail wire goes into socket 2 of the humidistat - which is the relay on the humidistat. Now you have 1 loose wire left - the second wire coming from the fan. That wire gets inserted into socket 1 of the humidistat - the second side of the relay. Now all your wiring is done.

Dave B
 
How about something like this? This is what I have been planning to use. Its called a Dayton dehumidifier plug

1UHG3_AS01.JPG
 
Regardless of what choice you went with , since you're dealing with 110VAC you don't want to have it wired outside of the wall. You want it in a junction box. I'm going to assume the Levitron unit is similar to mine, in that you wire AC power into the unit, and you bring the wires from your fan to the unit and it basically is a switch (automatic though).

Reason I went with what I did is because I could actually set the percentage of humidity I wanted the fan to turn on at. I will say the upside of the unit you have if you can mount it with a nice faceplate easily. I did with mine, however some modification was necessary to get it to work and be rigid.
 

Based on where it's humidity sensor is set it will depend on where you put the fan. My humidistat is next to my tank but part of the living space my tank is in. My fan pull directly from my tank space and the tank is enclosed from the living area. My humidistat is set at 35-40 percent depending on time of year. If it's set above 45 percent it would probably never kick on.

Now, that fan you're looking at is set at 60 percent. If that's going in a fish room, that's still pretty high and will constantly still feel a bit moist in the air I would think. You should probably strive for 50 percent or less humidity to avoid issues. It's too bad it doesn't have an adjustable dial because it would be nice to have it all build into one. I think you're going to want more control then it has though.

BTW, depending on how you set things up, a ventilation fan can be an integral part of cooling your tank. Mine certainly is.
 
I use (1) fan to pull the air out of the room vented to the outdoors, and (2) passive fresh air supply feeds from outdoors to provide the supply. I tried to make the room as air tight as I could, including using a all weather door for the room. I wanted make sure the air really was coming from outside vs from the rest of the house.

As for humidity control vs temp control. I bout the dual controller & I got creative with the application. Since one fan was more than enough air movement for me. I designed a relay with a dimmer switch and connected it to both outlets on the controller, and then sent the output to the fan. When the controller calls for temp reduction the fan runs on high speed. When the controller calls for humidity reduction, the same fan will now run in a super slow setting to remove the humidity. (temp control overrides humidity control if called for at the same time).

This works well for me. Hope this helped you
 

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Can you explain "passive fresh air supply"? What does that mean and how do you achieve it?
 
Can you explain "passive fresh air supply"? What does that mean and how do you achieve it?

Probably means essentially "a hole in the wall" :D Basically some vent. So when the exhaust fan turns on it creates a lower pressure inside which allows fresh air from outside to rush in. By making the rest of the fish room as air tight as possible from the house, you insure that most of the air in your fish room will come from the outside.
 
Probably means essentially "a hole in the wall" :D Basically some vent. So when the exhaust fan turns on it creates a lower pressure inside which allows fresh air from outside to rush in. By making the rest of the fish room as air tight as possible from the house, you insure that most of the air in your fish room will come from the outside.

But there would need to be a flap of some sort, as in a dryer vent. It would have to open inwards to let air in. Never seen that. Does it exist?
 
You'll have to wait for him to comment on that. But if you basically installed a dryer outlet backwards, so that the "outlet" was on the inside you could achieve a similar goal. However you'd need to make sure your fish room was really airtight on the house side for that to work effectively. Otherwise if the weather is mild no flap necessary?
 
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