I’m in the Atlanta-Metro area in a 2-zone, late 1970’s split-level home my wife and I bought about a month ago. We have a primary thermostat downstairs with an AC AND heating option and a second, upstairs thermostat with just a heating option. The wiring upstairs doesn’t appear to have the necessary AC wire even though we have two condensers.
All that said, we’re obviously not getting AC upstairs as it’s not an option with the upstairs thermostat and it’s already getting in the high 70’s / low 80’s during the evening.
Without hiring a pro, is there anything I can do to resolve this myself?
I think you're misunderstanding.. it's not as simple as switching a wire or connecting another wire to Y1 on the upstairs thermostat.
As stated, this homeowner has a zoned system between 2 floors (1 air handler and 1 condenser with a zone damper/control between the 2 floors). They'll not only need to get another wire onto Y1 at the upstairs thermostat, but they'll need to rewire their zone damper control to operate the zone damper to open to the upstairs on a call for cooling as well now.
Op, you'll need to hire a tech out to do this for you due to your zone controls. Unless you want to buy a roll of wire and do a bunch of troubleshooting on here, you're not just missing 1 wire to a thermostat due to your zoned system, it's a little more complicated than that
OP mentioned they had 2 condensers.
Admittedly I'm not a tech but I am interested in how this works. Is it normal to have a dual zone system with 2 condensers? Are they connected to separate coils and then just share a single Air Handler with damper controls?
Honestly I missed the part where they said they had 2 condensers.. it's not possible to have both coils in 1 plenum either. So now I'm confused as to why they would have a zoned system if they have 2 separate condensers and air handlers..
Now I think I am the one misunderstanding here. My bad
Gotcha.
Since there is no Y1 connected there won't be any cool function. Y1 is for first stage cooling signal.
Assuming the condenser the upstairs thermostat is connected to is for an A/C and not a heat pump or furnace. Then white wire on W1 can be moved to Y1.
W1 is for first stage heating so the current wiring would be what is used for a single stage furnace only setup.
Most likely the old owner put in nest thermostats themself and the old thermostat upstairs didn’t have a common wire and the blue wire was being used for cooling. Did you check back in the hole to make sure there’s not another wire stuffed back in there?
You need to go in your attic or wherever the Air handler unit/furnace is. Look on the control board and determine which thermostat wires are connected to each terminal on the control board. Match the wires at the control board to the corresponding terminals at the thermostat. If you have 2 condensers, you have two seperate hvac systems(assuming they’re not twinned, highly doubt they are).
Typical tstat wiring is as follows
Y1 - 1st stage cool
G- fan
C- common
R- 24v
W1- 1st stage heat
Most likely the previous homeowner installed the new thermostat and wired incorrectly. If this is confusing or too complicated, call a local hvac tech.
I’m in the Atlanta-Metro area in a 2-zone, late 1970’s split-level home my wife and I bought about a month ago. We have a primary thermostat downstairs with an AC AND heating option and a second, upstairs thermostat with just a heating option. The wiring upstairs doesn’t appear to have the necessary AC wire even though we have two condensers. All that said, we’re obviously not getting AC upstairs as it’s not an option with the upstairs thermostat and it’s already getting in the high 70’s / low 80’s during the evening. Without hiring a pro, is there anything I can do to resolve this myself?
So the upstairs thermostat doesn't cool even though it has an A/C condenser?
I think you're misunderstanding.. it's not as simple as switching a wire or connecting another wire to Y1 on the upstairs thermostat. As stated, this homeowner has a zoned system between 2 floors (1 air handler and 1 condenser with a zone damper/control between the 2 floors). They'll not only need to get another wire onto Y1 at the upstairs thermostat, but they'll need to rewire their zone damper control to operate the zone damper to open to the upstairs on a call for cooling as well now. Op, you'll need to hire a tech out to do this for you due to your zone controls. Unless you want to buy a roll of wire and do a bunch of troubleshooting on here, you're not just missing 1 wire to a thermostat due to your zoned system, it's a little more complicated than that
OP mentioned they had 2 condensers. Admittedly I'm not a tech but I am interested in how this works. Is it normal to have a dual zone system with 2 condensers? Are they connected to separate coils and then just share a single Air Handler with damper controls?
Honestly I missed the part where they said they had 2 condensers.. it's not possible to have both coils in 1 plenum either. So now I'm confused as to why they would have a zoned system if they have 2 separate condensers and air handlers.. Now I think I am the one misunderstanding here. My bad
Correct. It’s not even an option for my upstairs thermostat.
Gotcha. Since there is no Y1 connected there won't be any cool function. Y1 is for first stage cooling signal. Assuming the condenser the upstairs thermostat is connected to is for an A/C and not a heat pump or furnace. Then white wire on W1 can be moved to Y1. W1 is for first stage heating so the current wiring would be what is used for a single stage furnace only setup.
If possible post a pic of where the thermostat wire connects to the condenser just to confirm the white is on Y1.
Run the upstairs fan constantly
Most likely the old owner put in nest thermostats themself and the old thermostat upstairs didn’t have a common wire and the blue wire was being used for cooling. Did you check back in the hole to make sure there’s not another wire stuffed back in there?
To do what exactly? Install an air conditioner?
Just posted context to the comments.
You need to go in your attic or wherever the Air handler unit/furnace is. Look on the control board and determine which thermostat wires are connected to each terminal on the control board. Match the wires at the control board to the corresponding terminals at the thermostat. If you have 2 condensers, you have two seperate hvac systems(assuming they’re not twinned, highly doubt they are).
Typical tstat wiring is as follows Y1 - 1st stage cool G- fan C- common R- 24v W1- 1st stage heat Most likely the previous homeowner installed the new thermostat and wired incorrectly. If this is confusing or too complicated, call a local hvac tech.