Humidifiers and Dehumidifiers - RH Detecting Issues with Aprilaire 600A

I had my Aprilaire 600A humidifier installed about 2 weeks ago. This is the first few days where it was needed (but it rained a lot).

I noticed that it's not keeping our place at 35 RH (it's around 1250 sqft). Instead it's getting too dry. I even turned it up to 7-8.

I noticed that the RH reading on the aprilaire unit itself reads about 43%. However, when I read the RH anywhere in the condo, it's much lower than that (i.e. 28%) using two other types of sensors. Since the aprilaire unit registered at 43%, it shuts on/off a lot. Why is it reading so high when the real RH is about 28%?

Thank you

I had my Aprilaire 600A humidifier installed about 2 weeks ago.
By whom? You or dealer?

I noticed that it's not keeping our place at 35 RH (it's around 1250 sqft). Instead it's getting too dry. I even turned it up to 7-8.
Is an outdoor sensor being used, or is it in "Manual"mode?

Where is the humidistat mounted?

Installed by a dealer I found on the aprailaire website. It's on manual mode (at least that's what it says) at the bottom. The dealer said if I still have problems after Monday to give him a call.
I have it set to 7-8 (the humidify is now rising - my only concern is why it says the RH is as high as it is when 2 other independent things are much lower). So I just find it really weird and am curious if this is normal or if there's a reason it's reading too high (and therefore not coming up as often).

From what I can tell it seems to be mounted on the air-intake on the heating system itself. Is there a sensor there that comes off of the aprilaire device to detect RH - or is that build directly into the unit (where you select what RH you want).

Thank you

Is the humidistat above the unit on the duct?

The sensor is built into that, and should have an opening in the duct this mounts into.

I'll try to describe as best as I can - don't think I can post images.

The humidstat appears to be about the same level as the humifier unit (where the water panel goes), but on another side. However, the humidifer has a large metal pipe that goes to the ducts above the heating system that gets blown out to the condo. That large metal pipe isn't exactly installed flush up installed into the ducts. For example, it seems like some could leak out a little - not sure if that's common.

The air intake is actually about a few feet from the heating unit itself - just on the other side of the wall. The intake is at the bottom of the unit. It happens to be also right by the living room making it pretty loud whenever the heat does kick on.

The humidistat should be above the level of the humidifier.

I have a feeling that it's getting a false reading of where it's at now (the way I understand your lay out.

Are you able to take a photo of it?

Sure I'll take pictures now and post as soon as they are loaded.

So the humidifier itself puts moisture directly into the intake? (is that why you mentioned it should be above it)? For some reason I thought the humidifer was only mounted on the intake, but that the metal tubing took the moisture up into the ducts.

So the humidifier itself puts moisture directly into the intake?
That is correct.

The air flow is coming from the supply side (under pressure) and blows over the pad and into the return duct mixing in with the return air. (negative pressure)

Ok, can you see these two pictures?

For my unit, the intake is at the bottom of the picture. And at the top are the ducts to get the heat to the rest of the condo. Is that typical (or opposite) of normal systems?

It seems like the humidifer uses the bypass to bring the moisture to the very top - so hopefully not near the humidistat. But as you can tell they are right by each other. What do you think? And thanks for baring with me I don't know much about these systems and have been learning a lot thanks to this website!

http://i357.photobucket.com/albums/oo17/kbhit/Furnice1.jpg

and...

http://i357.photobucket.com/albums/oo17/kbhit/FurnaceTop.jpg

Yep, you are getting a false reading. That is way too close to the humidifier.

No, the air is NOT going up to the top of the furnace, is going from top down to the bottom mixing into the air flow.


Pop the cover off the humidfier, and you can feel the air flow sucking into the humidifier, and air blowing out of the bypass pipe.

I would ask the dealer to move the humidistat to the wall next to your t-stat (Take it out of the return box)

As for the pipe leaking is nothing to worry about.. Looks like they had a tight spot to work in.

Thanks. I agree - I wonder why they thought it may have worked where it was. Does it sometimes work that close?

Moving it to near the thermo-stat sounds like a good idea, seems like they would have to run some electrical cord through some walls, but doesn't seem like a long distance.

I am not sure why they did that.. But your lay out is very far and few in between. So maybe this person who put it in didn't know it would have any affect.

yes, they will have to run some low voltage wire to the new spot.

Thank so so much! I have one more question if you don't mind - before I speak to them on Monday.

That is - the light that says if the humidifer is on only turns Green when the heat is turned on.
1. If I tell my thermo-stat to run the blower (circulate air) even without heat, the humidifer still does not turn on. This means I can only get new humidity when the heater is working - which doesn't work well when I have the temperature turned down. Is this normal and correct?

2. If I could get it working with the blower - then theoritically I could get some sort of thermo-stat sensor to trigger the blower when it needs...

1. If I tell my thermo-stat to run the blower (circulate air) even without heat, the humidifer still does not turn on. This means I can only get new humidity when the heater is working - which doesn't work well when I have the temperature turned down. Is this normal and correct?
Correct, this is the correct and normal way to do it.. I've played with mine in the past, and had it come on with my fan (I run my blower 24/7) and the humidifier ran a lot more to keep up. So I switched it back to come on with the heat only, and it didn't run as long. Hot air helps evaporate the water better than room air temp.

2. If I could get it working with the blower - then theoritically I could get some sort of thermo-stat sensor to trigger the blower when it needs...
You could, but no need to get something to turn the fan on.. the only humidifier will do fine with the blower only is the steam model.


I am off to bed. Will be back tomrrow night.