- My Forums
- Tiger Rant
- LSU Recruiting
- SEC Rant
- Saints Talk
- Pelicans Talk
- More Sports Board
- Fantasy Sports
- Golf Board
- Soccer Board
- O-T Lounge
- Tech Board
- Home/Garden Board
- Outdoor Board
- Health/Fitness Board
- Movie/TV Board
- Book Board
- Music Board
- Political Talk
- Money Talk
- Fark Board
- Gaming Board
- Travel Board
- Food/Drink Board
- Ticket Exchange
- TD Help Board
Customize My Forums- View All Forums
- Show Left Links
- Topic Sort Options
- Trending Topics
- Recent Topics
- Active Topics
Started By
Message
Installing a smart thermostat
Posted on 7/23/23 at 9:59 am
Posted on 7/23/23 at 9:59 am
So I'm trying to replace my nest thermostat with a newer ecobee. First time I tried, stupidly didn't turn off breaker and blew control board fuse. Second time I killer power to ac at breaker, but somehow the wire still made an arc and blew same fuse. Not sure how the wire was able to arc with the AC breaker off. I know I'm stupid. Just wondering if you guys have any ideas/suggestions...
2
Posted on 7/23/23 at 10:05 am to RoosterCogburn585
Which “AC breaker” did you turn off. The AC’s outdoor unit is 220 and will be on a different circuit than the air handler in the attic which is 110. The thermostat is powered by the 110 air handler circuit
Posted on 7/23/23 at 10:09 am to MikeBRLA
Hmmmmmmm......sounds like that was my exact problem. Didn't realize that. Any easy way to tell which breaker the air handler is on? My panel isn't "completely" labeled.
Posted on 7/23/23 at 10:17 am to RoosterCogburn585
Go in the attic and unplug your air handler. It should be a regular 110 outlet plug.
Posted on 7/23/23 at 12:17 pm to MikeBRLA
quote:
Go in the attic and unplug your air handler. It should be a regular 110 outlet plug.
That, or sometimes they’ll have a toggle (“light”) switch if can flip off/on, but ultimately you’ll want to find the 120 circuit breaker for your furnace/air handler in the breaker panel and label that.
This post was edited on 7/23/23 at 3:02 pm
Posted on 7/23/23 at 2:07 pm to MikeBRLA
Only gas air handlers are 110 volts.
If you have electric heat it will be 220 volt, 2 pole breaker. Sometimes the air handler is 2 breakers, likely a 60 amp and 30 amp 2 pole. Or 1 60 amp
If you have electric heat it will be 220 volt, 2 pole breaker. Sometimes the air handler is 2 breakers, likely a 60 amp and 30 amp 2 pole. Or 1 60 amp
Posted on 7/23/23 at 6:07 pm to Cajun Invasion
quote:
Only gas air handlers
Furnaces
Posted on 7/23/23 at 8:09 pm to RoosterCogburn585
Sometimes the power for the control circuit is fed by its own 110V power source
Posted on 7/23/23 at 8:16 pm to MikeBRLA
quote:
air handler in the attic which is 110.
Not all of them are like. My HVAC system has a 220V breaker for the outside unit and another 220V breaker for the air handler. If you know how to read a schematic it will show you what voltages are being used. My unit has a step down transformer that is 220 input and 24V output. And that is what powers the control circuit for my unit
Posted on 7/23/23 at 10:08 pm to Miketheseventh
quote:
My unit has a step down transformer that is 220 input and 24V output. And that is what powers the control circuit for my unit
Unless the system is very old, the control system will always be 24V, otherwise the wiring to the thermostat would need to be much heavier gauge. The CPT (control power transformer) will be in the furnace in the attic. You can find the small thermostat wire coming out of the furnace and going through your attic and down the wall to thermostat. It will be a brown wire with either 5 or 6 #18 conductors/wires inside. The 24V power to the thermostat is usually the blue wire unless your HVAC installer did something different.
As others suggested, simplest thing is to unplug the furnace in the attic. If you want to chase down the breaker that’s fine too but will take longer.
Posted on 7/24/23 at 2:32 am to bapple
Just wait for a power outage. duh
Posted on 7/24/23 at 3:51 am to RoosterCogburn585
quote:
Any easy way to tell which breaker the air handler is on?
Turn the thermostat down until the unit cycles on then flip breakers one at a time until it goes off.
If you have a register in the same room as the breaker panel you should hear/feel it when to goes off.
Posted on 7/24/23 at 4:38 am to Miketheseventh
quote:
Not all of them are like. My HVAC system has a 220V breaker for the outside unit and another 220V breaker for the air handler. If you know how to read a schematic it will show you what voltages are being used. My unit has a step down transformer that is 220 input and 24V output. And that is what powers the control circuit for my unit
Thats how they all work. Gas Furnaces are 120 volt.
Posted on 7/24/23 at 4:40 am to DMAN1968
quote:
Turn the thermostat down until the unit cycles on then flip breakers one at a time until it goes off. If you have a register in the same room as the breaker panel you should hear/feel it when to goes off.
If you have a quiet system, then throw a small layer of toilet paper onto the return air grille. When the fan quits, the paper will fall off .
Page 1 of 1
Popular
Back to top
Follow TigerDroppings for LSU Football News