Trouble Matching Lennox Wiring to Honeywell Thermostat


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Old 12-02-12, 04:20 PM
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Trouble Matching Lennox Wiring to Honeywell Thermostat

Hi all,

I'm renting a place that has an old mercury-style Lennox non-programable thermostat, and I am trying to install a Honeywell digital thermostat. In the Honeywell installation guide they provide some information about alternate wiring labels, but some of my wires still don't line up. This is what the Lennox had connected to it:

Y (orange)
VR (purple)
X (yellow)
F (green)
M (red)
V (blue)
R (black)

After consulting the Honeywell manual, I got this:

Y=Y
VR=?
X=Do Not Use
F=G
M=Y
V=R
R=Rc

I'm still unclear where VR should go, it makes no mention of that. Also, can you have two wires connected to the same terminal? It says that Y is Y but it says M is also Y, not sure what to do there either. Can anyone offer some advice? This is my first post, please let me know if you need additional info.

Thank you!
 
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Old 12-02-12, 07:11 PM
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Borrowed this from a friend, here you go:
 
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Old 12-03-12, 06:18 AM
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Thank you for this, this helps.

There's still no mention of VR, would anyone think it foolish to assume VR and VC are the same thing? I would then be connecting VR from the Lennox wiring to RC on the Honeywell thermostat, any objections?
 
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Old 12-03-12, 06:59 AM
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Wait, also, according to the image, Y=Aux. Does this mean I have auxiliary/backup heat? Like I said, I'm renting this place, and I don't have much info about this system. I see that the wiring schematic on the heat pump is similar to this picture, the Y from the thermostat connects to the W1 terminal strip, but the strip only has two wires connected, not three like this image, so that makes me think I do not have an em. heat relay.

I can ask the owner about it, but if Y=Aux, and I have Auxiliary Heat, then I need an new thermostat because the model I got says it doesn't work with systems with heat pumps and aux/backup heat... but, like I said, I only see two sets of wires connected to any of the given points on the terminal strip. Any advice?
 
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Old 12-03-12, 01:24 PM
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Ok, ignore my last two replies.

I think I have it figured out, based on what the Honeywell manual says, and filling in the blanks from that photo posted by hvactechfw, I have come to the following conclusion:

Y=W
VR=R
X=DNU
F=G
M=Y
V=R
R=RC

My only problem now is that I have two wires that both need to be connected to R; do I need a different thermostat, or can I connect both wires to the same terminal on the thermostat? The wiring schematic on the unit (and the one posted by hvactechfw) says both V and VR are '24VAC', they just connect to different places... any advice?
 
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Old 12-03-12, 03:33 PM
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yes, you can put 2 wires on 1 terminal.
 
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Old 12-03-12, 08:07 PM
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this has solved my problem, thank you for your help hvactechfw!
 
 

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