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Questions tagged [thermostat]

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

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2answers
715 views

Replacement thermostat wiring

I have an American Standard heat pump AC. I'm replacing a White-Rodgers manual thermostat (where I move a switch from cold to heat) with a Honeywell RTH7600 (which will automatically switch from cold ...
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2answers
42 views

Honeywell WiFi thermostat install

My old honeywell thermostat did not have a C wire as it was ran on batteries. I did find a light blue wire when removing the old thermostat that was not being used. Looking at the furnace circuit ...
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2answers
436 views

Is it Code to support Class 2 (thermostat) wires using a gas line?

Related to this question. Our gas furnace, while quite functional, has some quirks in its installation. One of them is that the installers cut off the old (original to the house) thermostat wires at ...
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1answer
57 views

Identify this programmable thermostat?

A tenant in my rental home had the programmable thermostat shown below installed by an electrician friend. Unfortunately, neither the tenant nor the friend has its instructions and can't remember ...
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1answer
31 views

Green and red wire connected together on terminal

I am installing a smart thermostat but I found the old thermostat has the green and red wires both running to the g terminal. When installing the new thermostat I will be removing the jumper wire ...
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1answer
2k views

How to Wire 3 baseboard Heaters with 2 Thermostats

I have one 20 amp double pole circuit that I am planning to run 3 baseboard heaters on with 2 line voltage thermostats. I have already made sure the watt consumption for the 3 heaters will not exceed ...
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9 views

Manually Toggling Heatpump Reversing Valve to enable cooling

Background A Radiothermostat CT80 fails to signal heatpump cooling, so jumpering the RED node with the GRN (Fan) and YEL (Cooling) node has successfully enabled cooling. The weather became cold, ...
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12 views

Evaporator fan motor does not turn on, could it be thermostat?

If thermostat freezes, will it not turn on the fan motor? It will turn on if I spin it manually. Whirlpool fridge with freezer on the bottom.
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10 views

Thermostat frozen over

I have a whirlpool fridge, with freezer on the bottom drawer? Freezer part freezes, but does not throw cool air to fridge part. Took apart freezer to check fan motor, spin the fan blade manually and ...
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2answers
69 views

No C terminal on furnace to connect a wifi thermostat

I have an new Emerson thermostat and would like to connect a c wire so it always has power. I have an extra wire that's not being used, but I don't have a C wire terminal on my furnace. I'm wondering ...
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24 views

No furnace fan in cooling mode while hooked to a fresh air damper controller

I added a fresh air damper and control, ( Soler Palau MD6-ES24VK) to my furnace (2006 York GY9S). The damper worked great in the winter but now that I am doing some cooling, I noticed that the outside ...
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2answers
86 views

Ecobee install with AC system disconnected

My house which was purchased from a bank (foreclosure) was originally wired with both central air and heater (forced air). But when the previous owner left, he took the air conditioning unit. The ...
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2answers
56 views

how to install thermostat

Im trying to install a new thermostat but the wires dont really line up (not sure what to do about the blue). Which wires should be connected to which? existing thermostat and the new wires next to ...
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3answers
68 views

Is it wrong to install both a whole house humidifier and a whole house de-humidifier?

I live nearish Pittsburgh. Our summers can get pretty hot and humid and our winters can get pretty cold. We have been planning to get a whole house humidifier because the house gets really dry in ...
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2answers
70 views

what brand of thermostat is this

The cover is missing from this thermostat, so I don't what brand or model it is and I don't have the manual for it.
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1answer
35 views

Furnace blower comes on full time when the thermostat is set to Auto

I have a Maytag furnace and the blower motor comes on right away when the thermostat is placed in auto and stays on when reaching the temperature set point and the heat goes off. I have replaced the ...
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3answers
85 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 ...
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1answer
71 views

Aquatherm - thermostat is dead. What to check?

(Thermostat: White-Rodgers 1F80-51 Heating Unit is aquatherm, XUAQ22-2, this is a heat exchanger hanging off a hot water heater, and giving us forced air heat for a 500 sqft space. Unit and ...
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0answers
98 views

Thermostat Upgrade, furnace C-wire reading low voltage

OK so here is the scenario. Upgrading thermostat from dumb to smart (Ecobee). I've done 2 others in my house that required re-wiring so I have a good sense for what should be done but I'm stuck. My ...
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1answer
13 views

Use Sonoff thermostat TH10 in one room to control a Sonoff Basic in another room

For those who are experienced with the Sonoff devices, I need to check the temperature in my living room using a Sonoff thermostat TH10, and when the temperature is above a chosen threshold, I would ...
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1answer
324 views

What terminal to use on AC for C wire / nest dual transformer install

So i purchased a nest gen 3 and proceeded to install it. This is on a dual transformer system, separate boiler and AC system. The good news was i had a unused G wire on the Heat side that I was going ...
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5answers
2k views

Most cost effective thermostat setting: consistent temperature vs. lowest temperature possible

The problem: Our heating bills are about 25% higher than our average neighbors according to our bill, yet our temperature is always as low as we can stand it (mid 50's), we have excellent insulation ...
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0answers
72 views

Controlling one FCU with two thermostats

I have a chilled water fan coil unit that will feed two areas, living and the bedroom. I want to control the FCU with two thermostats, one in the living and one in the bedroom, (preferably) in a ...
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0answers
21 views

Will the existing wiring work with the new thermostat?

I am looking to upgrade my line voltage thermostat from a Dimplex mechanical thermostat to a Honeywell digital thermostat. Both thermostat has 2 wires on its back. Would the new thermostat work if I ...
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2answers
132 views

29 volts too much for a 24 volt thermostat?

I replaced a digital non-programmable thermostat with a programmable thermostat and the new thermostat keeps the house around 60-62 no matter what temperature I set. When I contacted the manufacturer,...
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3answers
234 views

Do I need a new thermostat?

This is my first winter in this home, just moved in this past July. So I get my electric bill and it's been running more than usual every since I moved in here. It wasn't too much more so I just paid ...
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0answers
23 views

CT80 Thermostat Wiring Diagram Selection

Which terminal should the brown wire be connected to the RadioThermostat CT80? The original thermostat was wired as depicted: The brown wire is connected to terminal E (not F). As I understand it: ...
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2answers
121 views

Electrical code and/or common sense requirements for thermostat wire

I want to install a Wi-Fi thermostat, but the existing thermostat wiring didn't have a common wire. The house was originally wired with two-conductor cable since it was a heat-only system, and then ...
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2answers
38 views

Do I have to turn off “everything” when replacing thermostats?

I am about to replace my two thermostats. There's a lot of switches on the "control panel" (litterally) for my heating system and I am not familiar with procedures and afraid to turn something off ...
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0answers
29 views

Are my new thermostats compatible with my system?

My two old Lux Pro PSP511LC are dying (LCD going out on both!) so I got two new thermostats from a friend he didn't need we both thought I could use. They are the Orbit Clear Comfort 83521 thermostat. ...
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1answer
59 views

How to connect a new thermostat with different terminals than the old one?

I have bought two new thermostats to replace my old worn out ones. We have a oil burner furnace with hot water radiators around the house. No cooling. The problem is that the two thermostats have ...
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1answer
58 views

Where to connect Blue C Wire at old furnace?

I have looked at other responses and each layout is a little different. Looking to connect a Smart Thermostat and need to know where to connect the Blue wire at the Furnace. See the attached picture....
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2answers
41 views

What's wrong with my heater?

My heater only turns on if the temperature inside the home is 68 degrees or above. If the temperature inside the home is below 68 degrees, I can hear the thermostat click when I turn on the heater but ...
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2answers
1k views

Help wiring a Nest thermostat in an unusual situation

The attached picture shows my current wiring. Notice there are two thermostats. The top one (Carrier, with four conductors) controls hot air heating. The bottom one (with two conductors, old mercurty ...
93
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7answers
509k views

How can I add a “C” wire to my thermostat?

So, the spiffy new wi-fi thermostats want power on the C wire from thermostat, but the old thermostat doesn't have a C wire at it. What's the easiest way to add the C wire/24 volt to the thermostat ...
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0answers
64 views

How can I install a Y wire for a Nest thermostat?

Installed a new Nest thermostat yesterday. My setup is a 4 wire system. Green, Blue, White, and red. I have central air and gas heat. They had the Blue wire "C" into the Y for the AC. Since the Nest ...
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0answers
228 views

C-wire on Weil-McLain CGA Series 2

I have an old thermostat with only 2 wires connected to my Weil-McLain CGA Series 2 boiler. I would like to replace it with a Nest thermostat. I need to add a C-Wire in order for it to work. Luckily, ...
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0answers
29 views

Nest E without common wire stuck in purge loop as soon as the Rheem heat furnace ignites

I have a honeywell hz432 and just installed a few NEST thermostats with a common wire and they seem to run fine. I added another NEST E thermostat, but this one didn't have a common wire, and when it ...
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1answer
17 views

New Thermostat Won't Engage Plinth Heating in Kitchen Island

I have two plinth heaters on either side of my kitchen island. Since the rest of the house is hydronic, I presume that these are hydronic (there is a zone valve at the boiler) with electric fans ...
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1answer
62 views

Millivolt fireplace turns on by the thermostat but will not shutoff

I inherited a freestanding direct vent fireplace and I'm trying to get it to work with a thermostat. It functions fine using the ON/OFF/PILOT switch but will not work with a thermostat. It is a SIT ...
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0answers
36 views

Smart thermostat that accepts TWO heat inputs?

I have a center split ranch that uses baseboard heating. The heat is divided into two zones, so the boiler is currently controlled by two different thermostats. And that has little to do with the ...
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1answer
37 views

Honeywell thermostat doesn't seem to be connected to standby generator

Honeywell thermometer doesn't seem to be connected to standby generator. Heater is linked to generator panel, but thermostat loses power with outage. Ideas??Thanks
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1answer
33 views

Heatpump Wiring Color Convention

A heatpump thermostat is to be upgraded. I am unsure of: Which color wire is the Common (thought to be BLUE) Where should the brown wire be connected? (B node?) Is the 'B' node in the photo ...
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0answers
55 views

turn on furnace blower with temp sensor

I have a wood stove in my finished basement. I am looking for a way to turn on the blower fan of my furnace once the temperature in the basement reaches a certain setting like 75 degrees, that is ...
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2answers
211 views

Using a ground wire as a thermostat C

Just theoretically, A C wire is just a return for 24v transformer right? So if you were in a situation where you have access to the slab, or just a standard outlet or switch receptacle could you wire ...
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0answers
24 views

Thermostat with an external transformer

I am trying to hook up a Vine TJ-610B-W WiFi thermostat to my heater. The original thermostat had only 2 wires, hooked to R and W, none hiding in the wall. I plan to use an external transformer for ...
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8answers
58k views

How can I use a separate transformer to provide a C wire to my thermostat?

Update 02/02/2019 I appreciate all the responses and help but unfortunately i must have not seen the emails stating there were responses! I am now looking into a NEST thermostat and was curious if ...
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0answers
40 views

Help adding C wire to furnace - Heat only system

Looking to add C wire into my furnace. Heat is currently running on two wires with older thermostats. Luckily the in wall wiring has three wires. Any help to point out the C wire for my setup? Or ...
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2answers
76 views

Two mysterious white thermostat wires in an unfinished wall outlet near the floor — what?

About 10 years ago, our house's builder added a small room above the garage. Since they left in a rush, they left an unfinished wall outlet located 1' above the floor. For 10 years, we ignored it. ...
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1answer
244 views

How to connect c-wire to Burnham Series 2 boiler?

I am trying to install my ecobee 3 light but the previous thermostat did not use any c wire. Fortunately, there was an unused wire in the wall and I would like to set it up as a c-wire. The problem is ...