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

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214 views

Are w1 and w2 both energized during a second stage heat call from the thermostat?

Short version: does two-stage thermostat always close W1 circuit when it closes W2 circuit, or they might be closed independently? Long version: I have two-stage furnace, currently connected to older ...
2
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1answer
4k views

How can I add a “C” common wire to this system? [duplicate]

I would like to add a "C" / Common wire hookup to my hvac system and get a fancy new thermostat. I've read Options for adding "C" wire to thermostat and still have some questions. First of ...
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2answers
854 views

Is there a filter-reminder thermostat that uses run-time instead of total time?

My HVAC filter is in my crawlspace and is a hassle to change. I don't want to change it more than needed. "Change it every month" is bogus advice because in some months (like May) we don't have to run ...
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2answers
145 views

At what temperature does a WiFi thermostat stop sending a signal to the router?

I recently purchased and installed a Honeywell WP6500 WiFi thermostat and thanks to Stack Exchange, got it up and running. I have a house in New Hampshire, which I use occasionally during the winter. ...
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3answers
76 views

A/c makes the lights turn on and off! No Joke!

The lights on the first floor, upstairs bathroom and upstairs Laundry room won't work. The breakers did NOT pop The air conditioning was running this morning but is not working now. When the ...
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4answers
953 views

Can I provide a secondary power source for my thermostat?

The thermostat at my home is set up with only the 24 power and return through the relay. I would like to add a 'smart' thermostat, however the line is fairly well buried in the wall/basement ceiling ...
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4answers
2k views

Is it alright that I did not turn off the power while installing my thermostat?

I just installed the Nest thermostat, I forgot to turn the breaker off everything seems to be working fine. Is it safe to assume it is ok?
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2answers
516 views

Honeywell T6360 wiring - follow installation wiring guide positions or numbers?

The following picture shows a Honeywell T6360 Room Thermostat wiring connections. You will note they are numbered in the order 2 3 4 1 5 6. The Installation Instructions that accompany this unit, ...
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2answers
970 views

What could cause a clicking sound in an underfloor heating controller?

I have a underfloor heating system installed in my apartment. Each room has a Uponor T-37 thermostat, hooked up to C-35 controller. The system is about four years old and recently I have noticed a ...
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5answers
6k views

How do I control a heat lamp with a thermostat?

My girlfriend is crazy about making bread. However, as the temperature is often very cold around here, I would like to make her a box in which the temperature can be controlled. I have purchased a ...
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4answers
514 views

Is there a special low temperature thermostat?

I have a gas ceiling mounted furnace for my garage. I want to set my garage at 35-40° F (1-4° C). Is there a special thermostat to control furnace at that low temp? (I've seen one works as low as ...
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2answers
2k views

Controlling separate heat and AC devices from a single thermostat

I have hydronic radiator heat powered by a gas furnace situated in one mechanical room of my house and a currently being installed central AC whose air handler is situated in another mechanical room ...
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2answers
212 views

How should I install a thermostat for a baseboard heater?

How would I go about installing a thermostat for my bedroom's baseboard heater? I've seen lots of articles on how to replace an old thermostat but I'm installing a thermostat for the first time here. ...
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2answers
1k views

How far apart is it okay to set thermostat during night and day

This isn't home improvement, per se, so please feel free to let me know if there is a better forum for this. I have been told by two people, one of whom is a boiler repair technician, that it's not a ...
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2answers
1k views

Can you terminate more than one common on the furnace C terminal?

TL;DR: Can you terminate more than one common on the furnace C terminal? Background: I've linked a diagram of how my non-programmable thermostat is currently hooked up. I want to replace it with a ...
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2answers
193 views

Can anyone identify this heating timer?

So, It's getting quite cold now and my central heating is just going on and off randomly. There is what seems to be an unbranded heating timer below the combi-boiler (Baxi). However I have no idea how ...
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1answer
76 views

Can I change my standard thermostat to a Wifi one?

I have a (quite standard) TR-010X T6360A thermostat that looks like this: And this is the wiring diagram: Can I install the Heatmiser PRT-TS WiFi Touchscreen Programmable Thermostat? This is the ...
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1answer
45 views

How to install thermostat with plug in heater?

My house has three electric wall heaters in different rooms used to augment the gas forced air that heats the whole house. These electric heaters are mounted on the wall, but plug into standard 120v ...
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3answers
91 views

can I install a new thermostat by just turning off the power instead of turining off the circuit breaker?

Can I install a new thermostat by just turning the power off at the servicemen's switch, instead of at the breaker?
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1answer
637 views

Should I replace my mercury switch thermostat?

We have an old mercury switch thermostat in our house, You know the type, gold ring, very common. We are in new England on a gas/steam system. There is no central AC. We have been told by more than ...
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1answer
972 views

Why won't my shower fully heat up?

I have a thermostatic shower, but I can only get it to be luke warm. The aquastat is set at 60, boiler at 165. The tap water in wash hand basin beside shower is very warm. I have taken the cover off ...
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2answers
965 views

How do I disable a thermostat to prevent it from turning on the AC?

I need to disable my thermostat from turning on the AC. Yes, covertly. I think one of my housemates is missing his native Antarctica. So, the thermostat still must be active & setable, but I want ...
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2answers
44 views

thermostat batteries replaced, AC unit won't start

Came home from work to find no AC. I checked the thermostat and the display was blank. After replacing the batteries and resetting the program, my AC unit never started up. I checked: - The AC unit ...
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2answers
3k views

Adding a C wire to a new Honeywell WIfi Thermostat

I am trying to install a new Honeywell touchscreen WIFI thermostat (http://www.homedepot.com/p/Honeywell-Wi-Fi-Smart-Thermostat-RTH9580WF/203926327?N=5yc1vZc5kl) and need to add a C wire to my ...
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2answers
593 views

Wifi Thermostat wiring

Replacing 2 Hunter thermostats with a Honeywell RTH9580 Wifi. Neither unit has a C wire - I'm comfortable with the upstairs high efficiency unit, but the downstairs older unit has thrown me for a ...
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1answer
709 views

Need to add common “C” for thermostat; can anyone indicate where to connect it?

We just got a new WiFi capable thermostat that, unfortunately, seems to use a form of power stealing in order to charge itself. The problem here is that our house is actually quite well insulated; the ...
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2answers
260 views

Thermostat / Oil Furnace Question

I have an old oil furnace and I am looking for some clarification as to how it is supposed to work. It heats water filled radiators through out the house. Currently it is connected to a thermostat ...
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2answers
2k views

Which terminal should I connect it to for a “C” wire when none are labeled “C”? [duplicate]

I am looking to replace my old battery operated thermostat with a new wifi model. There is no "C" common wire connected to my old thermostat. There is a blue wire that is at the thermostat but cut ...
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1answer
526 views

How to wire a new Honeywell RTF6580WF thermostat to replace a Chronotherm IV?

I have an old Honeywell Chronotherm IV thermostat that I am trying to replace with a Honeywell RTF6580WF wifi thermostat. I have a gas furnace and an air conditioner. Wiring for Chronotherm IV ...
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1answer
694 views

How do I wire this thermostat?

Hello I have a Honeywell FocusPRO 5000 Non-Programmable 1 Heat/1 Cool Thermostat, Large Screen. The wires it needs are: Conventional Terminals: Rc 24VAC power from cooling transformer R ...
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1answer
308 views

thermostat c wire question [duplicate]

I am looking to install a new thermostat that will require a C wire. I have a single stage A/C unit and my current thermostat has Rc, G, and Y wires. There is also an unused blue wire which I traced ...
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1answer
476 views

Why isn't my thermostat clicking on/off automatically?

My thermostat is not clicking on/off automatically, I have called my landlord and they replaced a very old one with a brand new one and it is still not clicking on off automatically, but will ...
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1answer
376 views

Which wall should I install a replacement thermostat on?

I'm replacing an old thermostat that is behind a door to our dining room, that is usually kept open, hiding the thermostat. Given that the wires come from above and I have some flexibility as to ...
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2answers
18k views

Why won't my A/C turn on after I replaced the thermostat batteries?

Our thermostat died yesterday, but after replacing the dead batteries with fresh batteries, and confirming the LCD screen was operable, our AC no longer turns on. I have attempted a factory reset on ...
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1answer
575 views

How to balance thermostat settings between zones to maximize efficiency?

I recently purchased a house so this is my first winter in it. The house was built in 1939 so most of the house is on a single heating zone using hot water radiated heat. The radiators are cast iron ...
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2answers
1k views

How do I diagnose a thermostat and HVAC that intermittently doesn't respond?

My gas heater for the whole house does not follow the thermostat settings on some mornings. I have set it to 70 degrees at 6 am but now it is still 60 at 8 am. This happens weekly once or so and seems ...
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2answers
390 views

Is there a thermostat-controlled corn heater sized for a shop/garage?

I'm looking for a way to heat my 4-car garage. Two bays are for cars, one is for the mower and other items, one is my workshop. I live in Minnesota, with very cold winters, so a heater is necessary ...
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2answers
10k views

Why won't my heater turn off when it reaches my desired temperature?

My wife and I purchased our first home this past year and we did a bunch of repairs up-front via a rehab loan, and one of the things we replaced was a very old thermostat with a new digital one. I ...
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2answers
48 views

Where do I connect my C wire from my thermostat when there are two transformers?

I have a Laars gas boiler that has 3 heating zones. I want to replace the old mercury honeywell tstat on the 1st floor (heat only) with a newer honeywell RTH9580 wifi model. I've taken pictures of my ...
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1answer
199 views

Where can I connect the C wire on the A/C side?

I’m trying to replace my thermostat with the Honeywell Smart-WiFi thermostat. Quick summary, I have an extra yellow wire which I’m making the C wire, but its not connected at the other end and I’m not ...
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1answer
45 views

Zoned oil furnace and AC thermostat question

I recently moved into a new home and wanted to replace the old thermostats with digital Honeywell ones. From what I understand the home has a Rheem 10 Seer (1996) compressor and a Williams oil furnace ...
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2answers
64 views

Honeywell home ventilation system with no c wire for thermostat. How can I substitute the g for the c without blowing a fuse?

I'm hoping to get some help with my thermostat problem. We bought our home brand new and it came with a very basic thermostat (non programmable and runs on batteries). I want to upgrade it to a wifi ...
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0answers
46 views

Using a second thermostat to balance temperatures thru fan-only control

Like many others, temperatures between the two levels of my house are uneven. This is particularly noticeable as spring arrives and the upper floor (above ground) enjoys solar heating (so the heater ...
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0answers
71 views

Why won't a NEST that shares control of a furnace with a conventional thermostat turn on the heat?

I have three floors in my home. The bottom floor has its own gas furnace and the 2nd and 3rd floors share another gas furnace. Everything was working great until I added a NEST to the first and ...
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1answer
326 views

How do I connect a C-wire on a Triangle Tube Prestige Solo 110? [duplicate]

I purchased a Honeywell RTH6580WF to use with my recently installed Triangle Tube Prestige Solo 110 propane boiler. I only have two wires at my existing heat-only thermostat. I understand that the ...
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0answers
83 views

Why doesn't my A/C get power when using the alternate C-wire thermostat hook-up method?

I changed my old Honeywell thermostat for a new Honeywell WiFi thermostat. I installed it just as the directions stated. I used the alternate C-wire method as the old unit did not have one. ...
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0answers
51 views

How can I add a common “C” wire to my thermostat? [duplicate]

Possible Duplicate: Options for adding “C” wire to thermostat I recently bought the Honeywell THM5320R Wireless thermostat. After going to hook it up I found what many others have, it ...
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1answer
183 views

How can I consolidate different heating/cooling systems into a single system?

I have 3 different types of heating/cooling systems that I inherited. Hot water heat. This heats the whole house/garage via 3 zones. Zone 1: Kitchen/Livingroom Zone 2: Bedrooms/Bath Zone 3: Garage ...
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1answer
1k views

How to connect Nest in Europe

I found a question regarding the Nest thermostat here. But that is only a question "Will it work?". Thanks to that I know it WILL, the problem is...HOW. I know the wire naming conventions are ...
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1answer
463 views

How can I install a nest thermostat with no wires?

I have zoned heating/AC/heat pump. My original thermostat on the wall is NOT connected to any wires, in other words it is wireless. I thought it had wires so bought the new Nest thermostat. ...