Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [thermostat]

Mechanical or electrical device used to control a heating, ventilation, and air conditioning (HVAC) system, or other temperature reliant system.

0
votes
1answer
34 views

thermostat connections with different size wires

my current thermostat has 14 gauge wires connected to it and the wires are supplying 24 volts to the thermostat. i want to get a new thermostat but will need 18 gauge wires. since the voltage from the ...
1
vote
1answer
70 views

Why is my thermostat turning the heat on too soon?

I have recently come across an issue with my thermostat and when and how my heat comes on. My thermostat seems to be an old round Honeywell. I set my temp at 65 typically. As of last night my ...
2
votes
1answer
117 views

Ecobee Smart Thermostat- Using Room Sensor as primary control

This is ultimately a fairly simple question about the Ecobee3 thermostat and the wireless room sensor functionality, but I'll explain my situation first. Twin home, 2 stories + finished below grade ...
0
votes
2answers
64 views

control for attic fan

I have an attic fan with an old (MH Rhodes 90015 /marktime) mechanical timer switch. I want to replace the timer with a thermostat (presumably a line-voltage thermostat). To my surprise, in the ...
0
votes
1answer
52 views

Replace existing thermostat with diy solution [closed]

I currently have a wireless Altech thermostat. Is there any chance I can replace it with an diy solution (based for instance on a Raspberry Pi)? The idea will be to only replace the transmitter and ...
0
votes
1answer
59 views

Can’t turn off power to thermostat

I’m installing a nest thermostat and trying to turn off power to the thermostat before doing so. I’m using a voltage tester and can see the wires coming in have power. I have two systems, one for ...
1
vote
1answer
154 views

Old Thermostat with just R and Y wires?

UPDATE: this may be R and V, not R and Y, although I'm still not sure how it was set up. I am replacing an old thermostat in my house (the house is from the 60s, I'm not sure how old the thermostat ...
1
vote
0answers
20 views

How to Run Fan Only with Thermostar Furnace With G Wire

I have a Thermostar Furnace that works great for Heating our home. We do not have AC and do not want that. But, we do want to be able to just run the fan without heat. The W and RH wires were ...
3
votes
2answers
63 views

Thermostat White-Rodgers 1F82-261 switches to stage 2 heat for no apparent reason

I am running a central heat system that uses a heat pump as stage 1 and a gas furnace as stage 2. The thermostat used is the White-Rodgers 1F82-261 which supports 2 stages of heat. When using regular ...
1
vote
1answer
165 views

Where is the C wire terminal on my boiler

I am trying to connect the T5+ smart thermostat to my oil based furnace. I see there are only two used wires at the thermostat R And W but 3 additional cores available. My boiler is a old Weil McLain ...
0
votes
3answers
80 views

Can I reverse my heating zone?

I have a three zone hot water boiler based heating system. The boiler is currently at one end of my ranch style house. The radiators appear to be directionless (no valves or anything). One of the ...
2
votes
1answer
118 views

How should the thermostat wires be connected to my furnace?

I have an Amana AMV90704CXBB furnace, and regular programmable thermostat. I took the furnace apart because I have to wash the blower motor wheel. It was covered in construction dust. In order to ...
2
votes
0answers
185 views

Where should I connect my C wire on Goodman GMP075-3 Rev.B

I am trying to install an ecobee4 to replace a digital battery powered thermostat. I removed the existing thermostat and found that there was a spare blue wire that was wrapped around the others that ...
1
vote
1answer
41 views

Finding Common Wire on Laars JVT boiler

Replacing mercury thermostat with wifi. I have just a red and white wire connected to current thermostat and boiler. There is a green present, but it isn't hooked to anything on boiler. So I can ...
0
votes
3answers
208 views

Making sure old Honeywell Thermostat (round dial) doesn't turn on

I've had to cover my baseboard heater with painter's tape and duct tape because I keep getting click beetles strolling into my apartment after 6pm (I live in Michigan, and the temps are dropping). I ...
1
vote
0answers
371 views

How to wire a Taco zone valve controller with ecobee

I'm having an issue with wiring my Weil McLain gas boiler. It was wired up fine and working for a single zone. I added (2) 4 wire zone valves in. So I now have 2 zones, a Taco zone valve controller(...
1
vote
1answer
23 views

re-wiring/retro-wiring a Carrier 40MVC024 ductless A/C for external thermostat: guidance

My server room has two air-conditioning units, with acutely counterproductive controls. I want to rewire them for external thermostats. Can I simply splice a traditional thermostat inline with the "...
1
vote
0answers
16 views

Do I need to replace the thermostat wiring leading to my boiler?

I have a boiler in an old building with four different apartments. There are two thermostats that call for heat from the boiler, and valves that direct the hot water to the respective part of the ...
3
votes
1answer
744 views

Why my baseboard heater won’t turn with new thermostat?

I have a pair of electromod basement heater. The label on each of them show them show 750/1000W. Power supply to this is 240V I am trying to replace the old manual thermostat with a progrmabale one. ...
2
votes
1answer
43 views

Upgrading from a two wire analog tstat to a Nest, need help

I am looking to upgrade from an old analog tstat to a Nest. My old stat had only two wires connected (R and W) but the wire bundle had three. So I tried connecting the green wire to C and then turned ...
0
votes
1answer
74 views

how to get 240V to 4 wire 240V thermostat

I have a 2 pole circuit breaker in the panel with a 2/12 cable connected to it. Black wire is connected to one pole, white wire is connected to other pole and bare wire is connected to ground bar. ...
2
votes
3answers
481 views

Wiring for ecobee3 lite

I recently purchased the ecobee3 lite and am now stuck trying to install them. I have 3 Honeywell thermostats I am looking to replace and my heating system is oil/hot water. My home was built in 1970 ...
0
votes
2answers
167 views

Checking voltmeter on my Honeywell Wifi Programmable Thermostat

I have a wifi programmable Honeywell thermostat. Worked fine for 3 years, this morning I turned on my gas furnace for the first time this year and it would not go off, even when I set the "Heat" / "...
0
votes
1answer
64 views

replacing old line voltage thermostat

My old 4 wire 240V mechanical line voltage thermostat stopped working. I want to replace it with a digital thermostat. Problem is I don't know the amp rating of the old thermostat. I checked with ...
0
votes
1answer
122 views

Wiring Baystat240a to Honeywell RTH2510 w/ picture

I tried to hook up the wires but all the lettered terminals on my old thermostat don't match the letters on the Honeywell thermostat. I have the AC working but I still have three wires left over. I'm ...
1
vote
1answer
224 views

Connecting Wood/Electric Furnace to Smart Thermostat

UPDATE: I spoke with an ecobee tech and they pointed me to an alternative solution. If I get an adapter called a "Fast-Stat Common Maker", all I need to do is figure out where to connect the C-Wire ...
0
votes
1answer
1k views

How do you remove a Carrier / Bryant Infinity thermostat control from the wall?

I have a Carrier Infinity system with model # SYSTXCCUID01-V thermostat/control. I need to temporarily remove it from the wall. I found a diagram of how to install it: (diagram source) I do not ...
1
vote
1answer
73 views

Ecobee 3 lite Installation — Confusion about C wire (on furnace but not at thuermostat)

I am about to install the ecobee 3 lite thermostat. On the thermostat end, there is no C wire - just the typical 4 wires - R,Y,W,... On the furnace end though, there is white C wire too, which I do ...
1
vote
2answers
185 views

How to hook up new 5 wire HVAC cable to newer HVAC unit with only 2 wires coming from it?? WITH PHOTOS

I have a newer HVAC unit that was installed using only 2 wires to control the heating only on the unit. The unit is capable of having AC connected and I would like to wire it so that it will work with ...
0
votes
0answers
25 views

Troubleshooting remote AC (heat pump)

BACKGROUND The system was working well in July: 6AM: AC turns on and reaches target temperature of 77 deg ISSUES Although it is a heatpump in cooling mode, I will refer to the system as an AC for ...
1
vote
1answer
82 views

My AC and Heat systems are separate, Can I wire one or both fan(only) controls to my thermostat?

My house used to have just Forced Air heat, but a year and a half ago, I had central air installed. When it was installed I had questions about the wiring they weren't addressed to my satisfaction. ...
0
votes
1answer
487 views

Turning off Power to Thermostat to Replace It

I'm replacing my old thermostat due to issues with it somehow not staying at my set temperature. It's a Simple Comfort 2001, and I'm replacing it with a newer model, a Simple Clean 2001L. Both of them ...
0
votes
1answer
40 views

Temperature monitoring for storage hot water system (RP-2 connection)

My HWS has a secondary outlet connection I don't use, and I'd like to use it to install a thermal probe I can monitor. HWS RP ¾ / 20 temp probe? Does anyone know of a practical way to install a ...
0
votes
0answers
42 views

smartzone or Furnace: c-wire to smart Thermostat

I'm about to add the c-wire to smart Thermostats. However, I'm not sure where to connect it as I have the following options: I have two zones, ( and I have two smart Thermostat) , I can connect the c-...
1
vote
2answers
96 views

Need to identify a common wire on my old HVAC

For Nest Thermostat 3, I am trying to identify a common wire on my old HVAC. The diagram can be found on the link below:
1
vote
2answers
1k views

Where do I connect a C wire in an old Furnace?

I am hoping to be able to upgrade to a smart thermostat but unfortunately my furnace doesn't have the "easy" option with an obvious C terminal. My furnace is OLD but it actually has the full 5 ...
0
votes
1answer
121 views

Connect Wifi Thermostat to Goodman GMP050-3?

I'm trying to connect up a wifi thermostat to Goodman furnace, specifically the GMP050-3. I've done some reading on this but I'm still not quite sure how to go about it. Specifically, I'm not sure ...
0
votes
0answers
33 views

Connecting separate boiler and A/C controls to one thermostat

Presently both the boiler control and A/C air handler have a 24V transformers, and are controlled by separate thermostats. I'd like to use one thermostat for both? To avoid possible phase conflicts ...
1
vote
2answers
55 views

Gas Furnace only, is Y wire needed?

I have force air (propane furnace). I would like to upgrade to a new "smart" thermostat, but they didn't run a C (common) wire which is required for most of these units to run properly. I do however,...
0
votes
1answer
334 views

Help wiring replacement Honeywell to Nest 3rd gen

Need help with identifying wires on Honeywell TH9320WF5003, using Nest compatibility checker to replace with Nest gen 3 One of wires look like "W- O/B, not sure which wire it really is nest doesn't ...
1
vote
1answer
81 views

How to identify the C terminal on my HVAC [duplicate]

As you can see I have a Y G W R/2 C/3 D/1 terminals on my HVAC. I am planning to change my thermostat to one that requires a c line. There are 2 spare lines available, however I am not sure which is ...
1
vote
0answers
61 views

Changing AC Fan Motor/Capacitor with No Luck

Issues with a central AC unit: Turned it on and heard a buzzing sound, but the fan didn't start. Started by looking at the dual capacitor. We happen to have two identical units, so I tried the ...
0
votes
1answer
522 views

Does the Nest thermostat automatically change modes?

I understand from the Nest website that the thermostat has heating, cooling, and heat/cool modes. I also know that over time Nest learns your preferences based on how you adjust the thermostat, and ...
0
votes
0answers
162 views

Nest for this setup

Is this the correct wiring setup for nest.
1
vote
2answers
971 views

Is the transformer bad on my Central Air Conditioner?

Need some help diagnosing a problem. My very old central AC unit isn't working. It's just AC and about a year ago I connected a C-Wire to the air handler when swapping the thermostat for a wifi ...
0
votes
0answers
103 views

Wiring for a new honeywell thermostat

I am trying to install a basic Honeywell Programmable thermostat, but the wiring is a bit different, and I am reluctant to start taking it apart. I have a Goodman heat pump, which is occasionally ...
1
vote
1answer
673 views

Where to connect c wire in furnace?

I'm trying to figure out where to connect a C wire from a thermostat to my furnace. I found this old post for the same furnace type (Trane XE70), but it seems as though a red wire goes to the terminal ...
0
votes
0answers
65 views

Thermostat Replacement - what to do with C Wire

I'm replacing an old Honeywell T8195B with a less old Honeywell T8112D1005. The T8195B has the same wires as the T8112D1005 - except the T8195B also has a C Wire. The C Wire location on the ...
0
votes
1answer
73 views

Condenser is always running

I recently rewired two thermostats into one Honeywell RTH9580WF1005 Wifi Thermostat. I ran a new wire and hooked up R and W to the oil boiler and Rc, C, G, and Y to the Goodman air handler. The Y is ...
1
vote
0answers
75 views

Correct wiring for Nest thermostat with dual HVAC system

Trying to wire up this new-fangled Nest Thermostat E (the cheapy edition) to my home HVAC system, but unsure of what to do. At the thermostat, I have G, W, Y, R, AND Rc wires, but the R and Rc wires ...