Lennox to honeywell thermostat

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  #1  
Old 03-31-20, 12:38 PM
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Lennox to honeywell thermostat

Im trying to replace an older lennox thermostat T874R1178 24F5601with a honeywell RTH 2300B
https://www.dropbox.com/s/lqwg8xzggk64mlw/2020-03-31%2013.01.51.jpg?dl=0
https://www.dropbox.com/s/zbcjw8x9v2tc2go/2020-03-31%2013.01.44.jpg?dl=0
https://www.dropbox.com/s/y6m18n3qv1rhjzw/2020-03-31%2013.02.05.jpg?dl=0
Old
R
Y
X
F
V
VR
E
L
M
A
NEW
B
O
G
Y
W
R
RC
What wires should go to what terminal? Thanks in advance!
 

Last edited by Lee Levesque; 03-31-20 at 01:13 PM.
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  #2  
Old 03-31-20, 01:00 PM
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Welcome to the forums.

There is no guessing.
We need the model number of the old stat as well as the new Honeywell one.
We prefer a picture of the old thermostat base to see the actual colors on which terminals.
How-to-insert-pictures.
 
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Old 03-31-20, 01:23 PM
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I added links for the pictures and added the model numbers
 
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Old 03-31-20, 01:28 PM
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Pictures uploaded

Pictures for thermostat thanks
 
  #5  
Old 03-31-20, 01:36 PM
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Ok.... I see the wiring one I needed. Working on the diagram.

To confirm...... this is a heat pump system with back up electric heating ?
If yes..... that thermostat won't work. It doesn't support back up heating.
 
  #6  
Old 03-31-20, 01:46 PM
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It's electric forced air furnace with ac. No heat pumps...
 
  #7  
Old 03-31-20, 02:53 PM
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Ok.... thanks.

X -------> yellow -----> C
F -------> green ------> G
V -------> blue
Vr ------> red
E -------> white --------> W
L --------> white
A -------> blue

I've got some problems doing the transpositioning. Since there are two whites and two blue wires.... that would indicate two cables. I need that confirmed. There are two different wires on V and Vr... that's also strange.

You may need to confirm wiring at the air handler also.
 
  #8  
Old 03-31-20, 03:47 PM
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Yes there are two cables feeding the thermostat

My guess at wiring the new thermostat is as follows
NEW------OLD
B---??
O---??
G--F
Y--M
W--Y
R--VR
RC-R
On the old one i still don't know what to do with wires X E L A
Thanks !
 
  #9  
Old 03-31-20, 05:12 PM
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You don't have Y or M used on the old stat.
A and L would not normally be needed.
You should only have one 24v R wire.

It is possible the V is common and Vr is 24vAC.

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  #10  
Old 04-01-20, 06:52 AM
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Hi, this pic may be of some help.
https://www.manualslib.com/manual/55...t.html?page=83
you may have to sort through this link for the Lennox unit.
Geo
 
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Last edited by Geochurchi; 04-01-20 at 06:56 AM. Reason: Add a link
  #11  
Old 04-02-20, 07:31 PM
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https://www.doityourself.com/forum/t...l-rth6450.html

Looks like V and Vr is the same as Rc and R.
The strangest part is that M is the compressor "Y" and R is the reversing valve "O".
 
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