Generalaire 900 E2 Humidistat Problem


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Old 11-18-07, 03:59 PM
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Generalaire 900 E2 Humidistat Problem

I just installed a Generalaire 900 bypass humidifier. Everything with the install went great (thanks to many posters on this site for tips/hints), but I can't get the humidstat to trip the solonoid valve when relative humidity drops significantly below the set point.

I'm a novice by all means when it comes to wiring, but I'll explain what I have done thus far. I'm fairly confident that I've wired the transformer correctly. Using a voltmeter I show 27v on the humidstat where the hot and neutral wires connect. The instructions call for a "jumper" wire from the neutral to the first "humidifer" port on the humidstat. I can also read 27v from this port between the "hot" solonoid connection (explained in a bit), telling me the jumper wire is working. The second "humidifer" port on the humidistat connects to one of the wires on the solonoid valve. The second solonoid wire is connected directly to the "hot" of the transformer. The "outdoor sensor" connections have been made as well. My limited knowledge of electricity is that when the humidstat calls for humidity, it will somehow complete the neutral circut closing the loop and activating the solonoid valve.

My first thought was maybe the solonoid valve is bad. So I manually completed the loop and it does open. I then thought maybe I wasn't getting enough volts, so I bought larger gauge wire (and a voltmeter). My humidistat powers up just fine and everything appears like it should be working.

I do have a few questions. First, is there a hot and a neutral wire from the solonoid? They're not labelled. Second, which post on the transformer is supposed to be hot? One says 24v and one says 12vA. I'm using the 24v as the hot and the 12vA one as the neutral right now. Third,
is it possible I got a bad humistat and it just isn't calling for humidity when it should?

Any and all hints/suggestions would be greatly appreciated. I'm an accountant by trade so feel free to shoot me any tax questions you may have and I'll try to "pay it forward"
 
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Old 11-18-07, 05:15 PM
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Ok, I pulled the manual, and you did it right..

Take the wire off of the HUM at the humidistat, and take a OHM meter and see if you have complete circuit With one probe on the first HUM, and other probe on the 2nd HUM. Turn it up to make it call for humididty.

If you are not getting a reading, the you got a bad humidistat.

My question is, is the transformer always hot, or cycling with the furnace?
 
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Old 11-19-07, 06:35 AM
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Thanks for your reply Jay. I'll run that test when I get home from work this evening.

The transformer is only hot when the blower is running. I have hooked it up to the "EAC" terminal. This causes the humidstat to only power up and display when the blower is running, but I checked and the humidistat does remember the last setting even though it shuts off between each cycle.

From reading more posts in here I read about one guy whose humidistat wouldn't work whenever the outdoor sensor was connected. He was having the same problem as me so I will try unhooking the outdoor sensor when I get home tonight. Only problem with that is the automatic humidity setting was the only reason I bought this particular humidifier in the first place.

Thanks, again, for your help. I will let you know what I find out tonight.
 
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Old 11-19-07, 08:32 AM
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Let us know what you've come up with.

I looked it up again, and I didn't see anything saying it has to have 24v at all times, so we should be OK the way it is.

I am leaning towards a defective humidistat.
 
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Old 11-20-07, 06:53 AM
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It is now working! I ended up calling the manufacturer who directed me to someone in their engineering department. According to the engineer, the humidistat has a built in safety switch that will not allow the humidifier to engage whenever the outdoor temperature is above 50 degrees. This safety switch works whether the humidistat is in manual mode or auto mode whenever the outdoor sensor is wired into the humidistat. Disconnecting the sensor disables the safety switch, which allows the humidifier to operate in manual mode.

The instructions/website/box do not mention this small bit of information anywhere, even though it might be useful to someone installing a humidifier in warmer Fall weather in anticipation of cold weather ahead. I falsely assumed that "manual" mode meant if I "manually" cranked the humidity up to 60% to test my installation it would engage.

So it turns out I had it wired correctly from the start. Many thanks to Jay for assuring me I had it wired correctly which lead me down a different path. I didn't want to call the manufacturer without knowing that the problem wasn't something I had done with the wiring configuration.
 
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Old 11-20-07, 11:55 AM
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Glad to hear that it is working, and I've learned something new about this humidistat.

Thanks for the update, and will keep this in mind if we do ever get someone else posting the same issue as you said you had.

Glad to help, and have a great Thanksgiving!
 
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Old 11-22-07, 09:02 AM
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Bought a Honewell HE360 Powered Flow-Through

Jay, I appreciate your expertise input. This is just awesome!
I have skimmed through the posts and find that most have much newer furnaces than I do. Mine has Air Ease on the front cover. On the data plate inside it shows Johnson Corporation Model HAS130BD . The following link is a photo of what is in my unit. http://www.flickr.com/photos/21141685@N07/?saved=1
I have a question:
I do not see a terminal block with HUM C W R Y1 Y/Y2 or any such connections. In fact I see no terminal block at all. It looks like just a straight 120 coming down to the switch on one side and the step down transformer for 24v on the inside where the gas valve is fed 24v and 120v is passed down to the blower fan. I am interested in picking off voltage for the humidifer to kick in when the 24v is supplied to the valve and drop out when the 24v is removed. Is there a simple way of doing this without using the sail switch? I'm getting the sense that this sail switch can be common issue. I like low maintenance worries. Note: The yellow jumper wire from one 24v leg to gas valve solenoid was put in there as a quick fix due to lack of wire connector availability. I'll be taking care of that.
Thanks again for your input. What seems such small and easy effort for you means a tremendous amound to those of us learning!
Paul
 
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Old 11-22-07, 11:51 AM
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One more thing on the HE360A

On the location of this humidifier unit, does it really matter exactly where it's put? The ONLY spot availabe on my unit is on the left side for the return air entrance of the unit, on the left duct, just as the air is returned before the blower fan compartment, which is under the burners to the right in the main furnace unit. No other location allows for room due to the size of the unit. Here is the link to give you a better idea. The duct to the left is the return duct. http://www.flickr.com/photos/21141685@N07/2055684148/ Also to note is the fact that this unit needs to be installed below that gas elbow you see at the left of the furnace. I have about 28 inches height (from floor to elbo) to play with. The unit is 14 inches tall. Do you see a problem with about 4 inches room for the drain tubing at the bottom of the humidifier? I might have to jossil it a bit as I need clearance to pull the front cover and service/replace the filter pad during yearly maintenance. Not an ideal place, but I have no other options due to the size of this humidifier and allowable space for clearance.

If this is critical as far as affecting humidifying efficiency, should I look for another smaller style/size that will fit above the furnace output?

Thanks!
Paul
 

Last edited by lebleup; 11-22-07 at 11:57 AM. Reason: Clarification.
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Old 11-22-07, 04:44 PM
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Paul,

Is there any place on the supply side??? The 360 can only be on the supply side of the duct work.. You could put it on the return. but you are going to be wasting a lot of water for nothing.

Your system is the old basic system.. You are not going to have any of the set up on your system.. Only thing will turn on your system is the A50 relay on the blower wire, or sail switch.


Also, on the photo with the gas valve, what's that yellow jumper wire doing there??????
 
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Old 11-22-07, 05:15 PM
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Hey Jay. Thanks for replying. Hmmm. There is actually no place on the supply side without moving water heater, piping..etc. I can tell that the previous owner had a humidifier at one time because of sealed off sections on the return and supply side with a bypass hole blocked off. The yellow wire. Apparantly that was put there as a quick fix, I'm guessing, due to the lack of a wire end to slip over the solenoid tab. Just guessing. I'll clean that up. Well it looks like I'll have to find a unit that will fit on the supply side, or just do a similiar set up the previous owner had at one time with a bypass on the supply side. Am I thinking correctly? Any model suggestions? I have a 2300 sq ft ranch with basement fully liveable. And about the A50 relay, if I go that route, where can one be picked up? Home Depot?

Thanks for your help.

Paul
 
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Old 11-22-07, 05:24 PM
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Yeah, you are going to need to look into a bypass unit.

Look into Honeywell or Aprilaire. I'd suggest the HE260 from Honeywell, can be found at Home Depot... If you buy the kit, you are going to get a sail switch, they work fine as well.

My store don't carry the A50 in stock, just the kit.
 
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Old 11-22-07, 05:46 PM
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Sounds great. Thanks for your professional opinion.

Paul
 
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Old 11-23-07, 07:13 AM
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Another question: How critical is the difference in height for the humidifier unit and the bypass hole on the supply side. I read that there should be a slight difference in height with the unit being slightly lower than the bypass hole in the duct next to it. What if it is like a foot difference? Any iinput would be greatly appreciated.
 
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Old 11-23-07, 09:24 AM
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As long you got a good path, should be ok..

Mine is on the return, 90˚ up, then another turn to clear gas line then I am in the supply ductwork above .. Not all furnace are going to have a perfect side line up..
 
 

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