Need Assistance with Humidistat Wiring

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  #41  
Old 09-20-10, 01:03 PM
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Originally Posted by Jay11J View Post
On my board there HUM and EAC. Maybe the wired marked HUM was put on the wrong spot (EAC).

Look at the board and see what you got. Let me know what you find tmrw.
First off, here is a link to the XC95 furnace install manual which shows the wiring diagram. XC95m Gas Heating Furnaces

I opened up the junction box and found the outlet box they mounted for the humidifier was wired to the bottom black wire on the 3 pin Hum connector on the Circuit board. The diagram shows that wire going to the HSI, hot surface ignighter, however, it is actually the top wire that goes to the HSI and the bottom wire goes to the Furnace junction box. Don't know why it backwards but the plug only goes one way so it is that way from the factory.

A second black wire from the EAC 2 pin connector on the furnace board was connected to the romex 110 line inside the junction box and ran from the junction box to the small switch they mounted just below the junction box, which then has a 2wire thermostat cable running over to the yellow wires on the Humidifier.

Since I had disconnected the old thermostat wires running from the furnace to the Humidifier previously to hook up the True IAQ, this "Switch" was not even being used. So, I tried disconnecting the wire from the romex cable going to the switch thinking maybe this would stop the outlet from being hot when fan only was on. What happened is it killed the outlet box completely even when the furnace was in "Heat" mode. I went ahead and reconnected this EAC wire back to the switch and the outlet is hot whenever fan is energized.

So, I am back to square one and looking for new ideas.
 
  #42  
Old 09-20-10, 05:22 PM
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Originally Posted by Depdad View Post
I opened up the junction box and found the outlet box they mounted for the humidifier was wired to the bottom black wire on the 3 pin Hum connector on the Circuit board.
3 pins? I see HUM H(ot) and HUM N(eutral).

The two wires goes up to the power box on the side of the furnace.

But then I am going by what I've seen so far. I have not seen the new XC95m models. it may be changed from that.



ran from the junction box to the small switch they mounted just below the junction box, which then has a 2wire thermostat cable running over to the yellow wires on the Humidifier.
Can you post a photo this "switch"?
 
  #43  
Old 09-20-10, 06:05 PM
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Originally Posted by Jay11J View Post
3 pins? I see HUM H(ot) and HUM N(eutral).

The two wires goes up to the power box on the side of the furnace.

But then I am going by what I've seen so far. I have not seen the new XC95m models. it may be changed from that.




Can you post a photo this "switch"?
Never posted photos but here goes:
http://img819.imageshack.us/img819/1723/dscf0001h.jpg
http://img534.imageshack.us/img534/6905/dscf0002rv.jpg
The switch appears to be wired from the junction box and gets it's 110vac from the EAC wire on the Circuit board. Then it apparently converts that 110 to close contacts and activate the humidifier via the yellow wires like the humidistat would do. I have no idea why it is connected to the EAC Black wire or how it was working with the Trane thermostat, but it did work. The switch just has the two A/C wires and then 3 out connectors to which the thermostat wire connects to two and runs over to the humidifier yellow wires.

As for the connections on the furnace circuit board, the HUM connector has 3 holes with a black wire coming out of the top and bottom hole, center is empty. The EAC plub has just two wires, blk and white.

I put a link in my last post to the XC95 install manual that shows the wiring diagram, but I cannot figure out the way the HUM and EAC work together.
 
  #44  
Old 09-20-10, 07:56 PM
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YOu looked here, and that's where you are seeing the HUM wire at?




[/QUOTE]

I didn't see anything in the service fact or the manual, but on my XV90, HUM is powered up only when heat is called. EAC is any time the blower runs.
 
  #45  
Old 09-20-10, 09:08 PM
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Originally Posted by Jay11J View Post
YOu looked here, and that's where you are seeing the HUM wire at?




I didn't see anything in the service fact or the manual, but on my XV90, HUM is powered up only when heat is called. EAC is any time the blower runs.[/QUOTE]

I am attaching a few photos of my junction box where you can see the two romex cables connected to it. The top one is attached to the HUN wire that runs from the Furnace circuit board where you can see the white plug with the two black wires. There is a bundle of 3 black and 3 white running into the bottom of that junction box that come from the circuit board. The other two sets of 110 wires are for the EAC and the main power in to the circuit board.

If you need more photos let me know.
 
  #46  
Old 09-20-10, 09:34 PM
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Originally Posted by Depdad View Post
I didn't see anything in the service fact or the manual, but on my XV90, HUM is powered up only when heat is called. EAC is any time the blower runs.
I am attaching a few photos of my junction box where you can see the two romex cables connected to it. The top one is attached to the HUN wire that runs from the Furnace circuit board where you can see the white plug with the two black wires. There is a bundle of 3 black and 3 white running into the bottom of that junction box that come from the circuit board. The other two sets of 110 wires are for the EAC and the main power in to the circuit board.


If you need more photos let me know.[/QUOTE]

http://img802.imageshack.us/img802/9886/dscf0004.jpg
http://img820.imageshack.us/img820/586/dscf0005y.jpg
http://img193.imageshack.us/img193/2015/dscf0006ei.jpg
http://img101.imageshack.us/img101/849/dscf0007g.jpg
http://img690.imageshack.us/img690/8673/dscf0008up.jpg
http://img810.imageshack.us/img810/8691/dscf0009cr.jpg
http://img180.imageshack.us/img180/8946/dscf0010ro.jpg
http://img823.imageshack.us/img823/8590/dscf0011i.jpg
 
  #47  
Old 09-21-10, 03:28 PM
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The first photo in the last post shows the junction box with the two romex cables attached and the bundle of blk and white wires running to it from the circuit board. I opened up the junction box again today and checked all the wiring. It appears to be wired correctly. The wires are clearly marked HUM and EAC on both the black and white sets coming from the circuit board. I checked to make sure the HUM wires were wired to the romex going to the humidifier's AC outlet on the side of the furnace and they were. I then checked the EAC blk and white and they were connected to the romex running to the small contact switch. From the contact switch there is the 2 wire thermostat wire running over to connect to the yellow wires of the humidifier.

I ran the system and set the Trane TCONT thermostat to heat and requeset for humidity. I then checked continuity across the thermostat wires going to humidifer and got a connection. As soon as I lowered the request for humidity, the continuity was disconnected As I said previously, the small switch converts the 110 from EAC leads to close the switch and completes the circuit for the 24 volt transformer in my Humidifier turning it on.

I checked the AC outlet on the furnace and it was hot whenever the fan was on, whether I set for heat, Air cond or just continous fan. The outlet did cycle off with the heat as long as the fan was not set to continous.

The last thing I tried was disconnecting the switch completely so there was nothing connected to the EAC leads coming from the circuit board, thinking maybe that was why the outlet stayed hot whenever the fan was running. It made no difference, the outlet was always hot with the fan running. Guess this new "Communicating" furnace has a mind of it's own and is set up different than it's predesessors.

I think the thing that confuses me the most is how the Trane Thermostat can call for the humidifier to come on through the EAC connection which is connected to the small switch that completes the circuit in the humidifier to activate it. I understand that the AC is provided to the humidifier via the HUM terminals, but how does the EAC trigger the switch to turn on the humidifier? All I know is it works perfect the way it is, but no provision to connect the outdoor temp sensor.

I'm at a lost now!!!
 
  #48  
Old 09-21-10, 06:13 PM
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Something must off been crossed on the board.

So I would move the EAC wire to the outlet on the side. then plug in the humidifier on this.

Then R from the board to R and W on the TrueIAQ. C back to B/C on the board.
 
  #49  
Old 09-21-10, 07:05 PM
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Don't know if that would work as the EAC wires are only hot when the Trane TCONT thermostat is calling for Humidity. When I lowered the humidity setting on the thermostat, the EAC wires no longer have 110. Apparently this is all controlled by the "Communicating" circuit board and the Trane thermostat. Wouldn't I would end up with the Trane thermostat and the IAQ humidistat both fighting for control of the humidifier?
 
  #50  
Old 09-21-10, 08:53 PM
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That's right..... Well, either just let the Trane stat control it, and just have to move the % up and down as needed.

or, just turn it up high, and let the IAQ take care of it.
 
  #51  
Old 09-21-10, 09:33 PM
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Originally Posted by Jay11J View Post
That's right..... Well, either just let the Trane stat control it, and just have to move the % up and down as needed.

or, just turn it up high, and let the IAQ take care of it.
I thought of that too, just setting the Trane humidity at it's highest and then let the IAQ actually control it. I will give that a try as that is the last resort. It will be a while before it gets colld enough to try it out though.

Incredible that Trane did not design this furnace to work with a temp sensor other than the one built into the A/C compressor. How hard would it be to design a temp sensor to plug into the furnace board. Maybe the Trane Rep and my contractor will get something out of the Factory, haven't hear back from them.
 
 

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