Wired my Aprilaire model 60; Furnance Always On?!?

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Hi.. i wired my new Aprilaire humidifier exactly as directed to an older Lennox furnace. The furnace now turns on, no matter what the thermostat setting.
It has something to do with the "C" connection: if I remove the "C" wire from the Aprilaire control (which is connected to "C" on furnace), no problem. As soon as i connect the "C" wire back, furnace turns on--even if thermostat is set to "system off".
I double-checked it all. Humidifier runs as per Test cycle. I installed Aprilaire humidifiers in the past no problem. What is going on?!???
Thank you, Dan
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There's no way it's wrong. I swear i have checked it all over and over; the wiring diagram from the box is so clear and simple:
Between Model 60 controller and Furnace:
R goes to R C goes to C W goes to W Gf goes to G on furnace
G from thermostat goes to G on humidistat
OMG it's exactly like that.
10 years ago i installed 5 Model 500s for friends, a Fanhandler, and an air exchange. You guys helped me out. They all still work perfect.
I am not a first timer.
I am going nuts tonight. Please help.
:Dan
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On Sat, 29 Jan 2011 17:58:02 -0800 (PST), Martinic
    OK, then it must be working perfectly :-)

    That time ten years ago - did you pay your minion dues ? I don't recall getting your check.
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It's wired correctly; there must be something wrong with:
a. older furnace needing different directions with new humidifier control? b. something wrong with the old furnace's control / wiring (the terminal strip / box buzzes)? c. incorrectly wired from the begining?
No--i didn't pay the dues. But i thanked profusely :)
:Dan
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On 1/29/2011 7:58 PM, Martinic wrote:

On some systems I've seen control voltage back-feed through the thermostat "G" connection and cause weird problems. If the system works fine without the new gadget, you my have to pick up a relay from your local supply house to isolate the control circuits from each other. I would check to see if "C" is the chassis ground like on many systems. Hook your DMM between the furnace cabinet and the humidifier chassis to see if you get a voltage reading when it's misbehaving. Google "Aprilaire Isolation Relay for General Purpose Use" You will find a lot of information.
http://www.shopwiki.com/Aprilaire+relay
TDD
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wrote:

Thanks guys.. i am done with it tonight. Going to continue research tomorrow and will follow your lead TDD. Argh. I hate it when things don't work like they're supposed to.... Good Night.
Dan
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wrote:

Hi.. not sure what you mean by "hook up DMM between furnace cabinet and humidifier chassis"--do you mean to actually touch the DMM leads to the cabinet sheet metal of the furnace? The humidifier is plastic-- what would i touch the lead to?
Thank you, Dan
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On 1/31/2011 12:23 PM, Martinic wrote:

I meant any metal chassis, There could be a metal chassis inside the plastic case, if not, don't worry about it. :-)
TDD
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wrote:

No metal except for brass outside of unit (solonoid/water valve).
But just to understand what you were thinking: if there's a problem with C in general, voltage would appear where it shouldn't, right? Are there other ways to check for this?
Dan
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On 1/31/2011 6:27 PM, Martinic wrote:

The "C" terminal often a blue wire is the 24 volt AC common and is usually attached to the metal cabinet of the air handler. Some of the manufacturers use their own color code but blue is the most used color for "C" common. I believe I posted a link to isolation relays that can be used if a humidifier is misbehaving and the best relay in my opinion to use is a current sensing relay that will turn on the humidifier whenever the air handler blower motor runs. Of course, use a humidistat to turn off the humidifier if you choose to run just the blower or AC.
TDD
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your installer is an idiot.
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I am the installer. I am not an idiot--i swear it. But i am missing something, obviously don't have the experience for this situation, and need someone to point out what's obvious.
The Lennox furnace is really old, and the terminal strip is located outside the unit sticking out of a box labelled Honeywell. It buzzes, but the buzz goes away after i connect the "C" from the humidistat.
Everything was working fine before i connected the new humidifier control (as per directions). It's not my house btw.
Thank you, Dan
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Steve.. i meant that i am the one installing the humidifier. Are you saying that the original furnace is installed incorrectly? I have this feeling that there's a problem with the ground or whatever the "C" is for.
Dan
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On Sat, 29 Jan 2011 18:07:25 -0800 (PST), Martinic
    I'm pretty sure he understood that ;-)

    No, he said you're an idiot :-)

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wrote:

It appears that the idiot installer has wired the controls incorrectly.
If the furnace board doesn't have a "HUM" terminal, then it probably falls into the "Jurassic" catagory and needs to be updated/upgraded and or replaced anyway.
Either way, it helps a lot to *READ* the installation instructions for the furnace, dehumidifier, and controls with specific attention to the control wiring and setup.
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On Jan 30, 6:56pm, "Stormin Mormon"

Are you talking about the Aprilaire Model 50 current-sensing relay? I suppose i could buy that and install it, but the humidistat that comes with the humidifier already has a function to humidify even if no heat and besides, it's *supposed* to work! This is a very simple hook-up; i think it has to be a simple problem too.
I want it to work like it's supposed to!! :)
:Dan
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On Jan 31, 4:54pm, "Stormin Mormon"

I can take pictures!! lol
:Dan
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On Mon, 31 Jan 2011 16:33:27 -0800 (PST), Martinic

    You'd probably fuck that up, too.
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On Jan 31, 7:39pm, "Stormin Mormon"

I will do so next time i'm there (it's not my place where i'm installing this). Maybe it's this new girlfriend that's the problem ha ha
:Dan
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Martinic wrote:

Hi, Are you sure it is model 60? Mot 600? I notice your email add. shows you are in Canada. I am in Calgary. G is furnace fan control lead, C is 24V AC control voltage common lead, W is heat control lead, R is 24V AC control vltage lead. Remember humidifier comes on only when furnace comes on and fan is running. Wonder if you left out humidistat? What is your thermostat?
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