Humidifiers and Dehumidifiers - Too much humidity with Aprilaire 600

Hi All.

I have a very strange problem. I have installed Aprilaire 600 humidifier on cold return with hot water because of space limitations. I also installed A50 relay so humidifier will work when fan is on and sensor inside my not heated garage. Now the problem is even with settings on "1" on humidistat the humidifier is running constantly generating about 45% of RH. I also tried to run humidifier in manual mode, but it still generates too much humidity. With setting 1 it generates around 35%. I live in MN and it was pretty cold for couple of weeks so if run humidifier then my windows are getting too fogy.

I'm currently running it in manual mode with settings between 1 and "off" generating about 25% RH. I prefer to run humidifier in auto mode so I don't have to watch temperature every evening and change setting manually.

Anybody has any suggestions what is wrong. I thing it could be humidistat is not measuring RH properly (???) and it doesn't shutdown the water valve, but I have no idea on how to verify this.

Please help me.

Thanks :wall:

Is the humidifier shutting down when there is no call for heat??

I agree, with our temps here in MN, will need the Auto/outdoor sensor to control the humidity..

Odd weather we are having.. 45˚ today, and Tuesday night -10˚!!!

Yes it does , but it depends if fan is on or auto, because installer wired it into fan blower. I think that humidistat is not measuring HR properly.

Is the humidistat mounted on the return?

If it is, you know if it's open behind the humidistat?

Yes, it is mounted on return and yes, there is an opening behind the humidistat

I am going to guess you may have a defective humidistat. I would contact whomever you got the unit from and ask for a replacement.

Do you thing if I will change humidistat location and move it to plenum(supply) side may change things?

No, DO NOT put it on the supply.. They can be only mounted in the return, or in the living space.

I just want to give an update on this. May be somebody will find this helpful.

I moved sensor outside and looks like its working ok. I don't get foggy windows when it's getting really cold out at night. But humidistat still is set to "1" and I think I figured out why I can't set it higher and not get moisture on my windows.

My utility room is small and the door is always closed. So when heat is on, I think humidistat is reading a low humidity because it is hot and dry in that room so it keeps valve open. Is this makes sense?

Now the question is: Can I try to move humidistat to a different place on return to compensate for this? Or what else can I do?


Thanks

By the way, I forgot to mention that I did switch my Honeywell thermostat to 3 cycle from 6. Should I reverted it back or should I keep it. My furnace is not high efficiency it is only 82% I believe.

What are the cons and pros for setting it on 3 vs 6( in my case) ?

Thanks

:eek: I think mine is mounted in the hot air side!!! I installed it like 3 years ago and havent had any problems (I dont think) but I better check this when I get home to make SURE!!! YIKES!!!

The humidistat can be mounted else where, but is there a cut out behind the humidistat to read the humidity in the return not the room itself?

Leave it at 3, it will be easier on the equipment, you won't have as many on and off cycles.

Y would your humidity control be mounted in a utility room unless your mother in law sleeps there, the controller needs to be in a living area or preferably in a sleeping area.

Y would your humidity control be mounted in a utility room unless your mother in law sleeps there, the controller needs to be in a living area or preferably in a sleeping area.

because that is where my furnace is.

The humidistat can be mounted else where, but is there a cut out behind the humidistat to read the humidity in the return not the room itself?

yes there is, but room is too small and it gets very hot in there and dry. I placed a weather station in the room and when furnace is running it would get about 84F and only about 20% RH when thermostat is only set to 71F in the house.

yes there is, but room is too small and it gets very hot in there and dry. I placed a weather station in the room and when furnace is running it would get about 84F and only about 20% RH when thermostat is only set to 71F in the house.

When there is a cut out behind the humidistat, there should be no affect of it from the furnace area itself. Unless the a lot of gaps between the humidistat and ductwork that the air is being sucked into it around there.