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What is model on old thermostat?
Also what is model on the outdoor unit? That will tell me if it is a heat pump.
Ok first of all, your system is definitely not a heat pump so we want 0 selected as system type.
But we have an issue here with this second thermostat being in the circuit.
Normally if you have a second thermostat it is operating zone dampers for upstairs.
The 0 terminal is for energizing the reversing valve in a heat pump and not used with a conventional system.
It sounds like previous installer may have been using that O terminal somehow to connect the second thermostat.
I am not familiar with how that is done so I am going to open this to other experts who may be more familiar with the setup.I did not realize there was a second thermostat.
I have opted out of the question to see if perhaps other experts may have more information and can assist.Please do not rate or reply as that will send question back to my desk.Please stand by to see if another expert can assist further.
If you had a separate O and B terminal on the old unit you really need to get a thermostat with a separate O and B terminal as these older systems can not run like a newer unit just getting rid of the B and taping it off.
If you have an O and B wire it has to be a heat pump system
That is incorrect...having an Oand B wire does NOT mean you have a heat pump.
The Bryant 561 is a regular ac unit
The 373 furnace is regular gas furnace
The reason you have an O and B is because you are running a zone system. The o and b are terminals that go live in either heating as an accessory or cooling as an accessory.
You do NOT have a heat pump...you have a zoned system. You cannot use the wifi in place of the current thermostat as it is a "Master" and the other thermostat is secondary..meaning it can only do what the master lets it do.
It is the way you are configured. You have 2 thermostats without a zone panel...the block with coil wires is a relay..that is deciding which thermostat is operational.
The B terminal activates with heat and the o terminal with cool. The issue is that the main thermostat overrides the 3 wire....the wire is known as a slave because it can only operate when the master thermostat is not.
End result is if you want wifi on the master you need different terminals for o/b...or do away with the second thermostat and let the master control the entire house.
Yes like I stated you will need a thermostat with the O and B separate to run it
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Unfortunately the o/b is NOT for heat pump as previous peer mistakenly noted.
Here the O and B are accessories...Not a O and B (common) as evident by "taping off" comment.
So in summary, the unit is not a heat pump as instructed.....the b terminal is not one that can be taped off as instructed
They use the relay to differentiate between what thermostat is given control...
If you have further questions ask for Billy as I recognized that you had a dual thermostat arrangement and not a heat pump.
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Unfortunately the o/b is NOT for heat pump as previously noted.
If you are willing to change the system we can use the thermostat.
Do you know if you have any dampers in the system to separate zones or simply have 2 different thermostats for one furnace?
we are going to do away with the upstairs thermostat and the relay.
remove existing thermostat.
Install wifi and wire as follows:
red to R/Rc
white to W
Yellow to Y
Green to G
Blue to C.
Now at furnace....
red to R
yellow to Y
green to g
blue to C
Do not use brown
This will connect main thermostat direct to furnace/ac and give complete control and wifi
you do..it may be labeled Com....
if you have ac...two wires come into furnace from outside...one goes to Y with yellow from thermostat and the other goes to C (com)
Com = common
you are correct..just tape off all the other wires.
You see the thermostats really cancel each other in this design.
Lets say down stairs is warm enough, but upstairs needs heat...all it does is turn the furnace on until the upstairs is warm..which overheats the downstairs...
So really in your case you just want one thermostat anyway.
Wire as described and just get back to me...make sure furnace is off when proceeding
in the furnace...there should be 2 wires that come from outside.
One will attach to Y and the other to Com.
just like the thermostat wires.
Follow the 2 pipes from ac coil on the furnace...one is covered in black rubber...there should be a wire that runs with it.
the Com terminal should have one of the ac wires in it.
is the Com currently empty or has a wire?
so someone has rigged the thermostat for cooling to upstairs stat and heating from downstairs.
Post a pic of the wiring in furnace tomorrow and I can see and direct easily.
use the attach file link...or it may even be a paperclip...or use a file share site like flikr. tumblr, mediafire..etc
yep...you going to have a wire nut somewhere joining wires...
The end result is this..
we need 5 wires from the thermostat (wifi) to furnace.
from furnace out to ac we need 2 wires...I am not talking about main power wires...but thermostat wires like shown.
We can forget/abandon the upstairs wires and thermostat...but we need the 5 from furnace to thermostat and 2 from furnace to outdoor ac.
Yes let me know when you locate them or if you still need help
just let me know and we will wrap up.
Just respond to "Billy"....and we can wrap this up.
ok, the issue is where the wiring changes color. It is unlikely it is inside a wall...but could be tucked in a joist space.
So we 2 cables coming in..one from ac one from thermostats.......can you follow the wires at all before they go through floor or attic for the splice?
Just let me know if you have got it yet
The old thermostat did not need a common. The entire issue right now is if we had the same 5 wires run from the furnace to the thermostat we would be fine...but the 5 wires at furnace are not the wires at the thermostat we need.
Could the wiring be behind one of the thermostats? (splice)
at upper thermostat..twist the r and w wire together.
Then try lower thermostat
yes..but we still need blue to common
wow...well this can be done...but we need to eliminate that relay and have the 5 wires that leave furnace terminals be the 5 wires that go to the thermostat (with no splicing).
I am afraid I will have to open this to the others if we cant get a dedicated 5 wire from furnace to thermostat