Picking the right thermostat.
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Picking the right thermostat.
Morning, I just moved into a new house and am looking at getting a smart thermostat. I grew up in a house with just oil heating and AC's in the rooms so a swap was easy, but now I have a CA system as well as oil. I just want to make sure I buy the right thermostat and know if I need to run a C cable. Here's what the guts of the older one look like.
#2
Welcome to the forums.
You have two systems controlled by that thermostat. Two distinct cables.
Cable 1............... The heat is on red(Rh) and white(W).
Cable 2............... The A/C is on red(Rc), green(G) and white(W).
You absolutely need a C connection and it comes from the A/C air handler.
Check and see if there are any cut off wires in the A/C cable.
You have two systems controlled by that thermostat. Two distinct cables.
Cable 1............... The heat is on red(Rh) and white(W).
Cable 2............... The A/C is on red(Rc), green(G) and white(W).
You absolutely need a C connection and it comes from the A/C air handler.
Check and see if there are any cut off wires in the A/C cable.
#4
You have two options.....
1) run a new cable down to the stat. (recommended)
2) you can lose control of the blower at the thermostat and use the fan wire as the C wire.
With this method.... there is no more "FAN ON" mode.
1) run a new cable down to the stat. (recommended)
2) you can lose control of the blower at the thermostat and use the fan wire as the C wire.
With this method.... there is no more "FAN ON" mode.
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Sounds good, sorry if the info I was giving wasn't nearly helpful enough. By oil heating I mean that I have furnace and baseboard heating. And the cooling is a Goodman A24-00. You wouldn't happen to have a link to a wiring diagram so I can put that C wire in properly?
#6
C is the big light gray wire under your thumb in the picture that you posted.
The AC condenser connects to stat Y and air handler C so you will end up with 2 wires connected to the air handler C.
The AC condenser connects to stat Y and air handler C so you will end up with 2 wires connected to the air handler C.
#10
So have we helped you make a decision ?
Any more questions ?
The Ecobee 3 is a good choice...... Honeywell T6 is another.
Any more questions ?
The Ecobee 3 is a good choice...... Honeywell T6 is another.
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Yeah you guys have been a great help thanks a ton. I was looking at the ecobee3 before I took to the forums so I'll go with that and hopefully not blow up the house in the process
#13
In your picture in post 3...... that white/gray wire in your thumb is C. You can connect right there.
#16
In your picture..... there is a three wire cable. This cable goes to the stat. If it's still being used..... R (red) goes to orange color. G (green) goes to yellow and white goes to red of the A/C condenser.
How did you get C to the stat ? One wire.... new cable... ?
Last edited by PJmax; 01-31-20 at 03:37 PM.
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I used the white wire that's connected to the thick grey cable, because from what I understood was that since it was connected to the grey cable, it would act as a C. But obviously that didn't work. So can I just add a third cable to the grey cable and white wire twist and use that as my C? As I was going over the ecobee instructions it seems that the main issue I'm coming up with is that I have a dual transformer system. I just can't figure out where the C wire is supposed to start at the A/C.
#18
Ok..... let's just take a step back. From what you've said and what I see in your pictures you have three wires between the air handler and the thermostat. You need a fourth wire.
How are you going to get a 4th wire to the thermostat ?
How are you going to get a 4th wire to the thermostat ?
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I was planning on snaking it from the hole in the wall to wherever the C needs to start from. I know easier said than done, but that's the plan. I've run ethernet cable through the house so I know it's a pain but doable.
#20
Ok.... so that wire you are going to run connects to the C of the thermostat and the gray wire at the air handler.