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

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1answer
3k views

Convert line voltage heating system to use low voltage thermostats

I currently have two line voltage ceiling radiant heating systems in my condo each with their own DPST thermostat. I'd like to use low voltage thermostats such as the nest. I found this ...
0
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1answer
640 views

Options for adding “C” wire to thermostat [duplicate]

Possible Duplicate: Options for adding “C” wire to thermostat I am upgrading to a newer thermostat that requires a constant 24 volt feed, I have an extra (unsused) wire in the ...
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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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
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 ...
3
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2answers
2k views

Is there a through-the-wall A/C that works with external thermostats?

Our two-story A-frame house only has duct-work downstairs in the crawl-space, with vents in the floor. It gets quite hot upstairs during the summer, but because the square footage of the upper floor ...
4
votes
4answers
903 views

Risk from installing a “Nest” thermometer without shutting off home power?

I'm trying to install a new Nest-brand thermometer in my parents' house (unscrewing a thermometer from the wall and screwing on the new one. The first instruction in the manual is to shut off power ...
2
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1answer
143 views

When I set the thermostat to X degrees, is that the temperature at which air is pushed out through the vents?

My hunch is that most ac units aren't that sophisticated, and they just pump air that is "cold enough" or "hot enough" and pump it until temperature rises to the specified value. Is that right?
2
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1answer
2k views

Can I pair two thermostats to work with a single zone system?

I have a southern California two-story home built in the late 70's. Its a single zone system with both heating and AC. The thermostat is located downstairs. In the summer the upstairs gets too ...
4
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5answers
20k views

Would the “Nest” thermostat work outside US?

Looking at this Nest question reminded me that I'd really want one of these for my future house. The Nest website says that it's currently only available in the US but I'm wondering whether that is ...
5
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2answers
2k views

Reviews on Nest Thermostat - That Learns [closed]

I am just wondering if anyone has used Nest | The Learning Thermostat. At $200 it is very expensive, and I wanted to know if it is worth the price!? Is it practicle, is it actually smart? How precise ...
2
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1answer
308 views

Will I see any performance gains if I reconfigure my thermostat to control the second stage of my 2 stage furnace?

Our furnace is a two stage one that was installed last year (a Bryant 80t). When it was installed, it was installed with a thermostat for a one stage furnace. This appears to be because this model ...
3
votes
2answers
1k views

Trying to wire a 240v line-voltage thermostat

I am trying to replace my old 240v line-voltage thermostat with a modern version. The problem is that after wiring the new version in like the old it doesn't work. I have (2) 12-2 wires coming out of ...
1
vote
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 ...
1
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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 ...
3
votes
1answer
336 views

Should fan on heat pump be delayed turning off when system stops?

I have a heat pump system with emergency heat. I have a Honeywell RTH7600D thermostat. When the heat is running and I turn the temperature down, the system immediately stops. Isn't this inefficient ...
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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 ...
34
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4answers
127k 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 ...
4
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3answers
1k views

Apartment building's thermostat located in unheated common area is cooking the tenants

In my apartment building, we have a steam heat system with radiators in each of the six apartments. The thermostat is located in the stairway/common area, where there is no radiator or exposed heat ...
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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
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 ...
5
votes
1answer
132 views

Does lack of zone control delay hurt heat pump?

I had a new HVAC single heat-pump system installed with dual zone controls: 2 thermostats and 2 dampers for separate zones. The system works, but the zone control board does not have any time ...
3
votes
2answers
2k views

Can I piggyback a thermostat with a C Wire hookup on a furnace?

I'm trying to install a new thermostat that needs a C wire hookup. There are currently 4 wires running from the thermostat to the furnace, none of them are a c wire. When I look at my furnace itself ...
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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 ...
14
votes
4answers
10k views

Why don't programmable thermostats automatically switch between “Cool” and “Heat”?

While I can set my house to be a particular temperature, I still have to manually switch it between "Heat" and "Cool" mode, and this seems to be true of every thermostat (programmable or not) that ...
5
votes
1answer
644 views

Is there a wireless thermostat that will make relocating easier?

I've got a single zone which covers all three upstairs bedrooms in my home and the thermostat is located in the master bedroom. We prefer it to be somewhat cooler at night, but the baby in the ...
6
votes
4answers
2k views

Buying a programmable thermostat to replace a manual one: any considerations?

I'm about to look for a programmable thermostat to replace a manual one. There are already a couple of good questions on thermostat replacement that make the task seem pretty straightforward for ...
5
votes
2answers
1k views

Line voltage thermostat to shut off attic fan when outside temp is close to inside?

I have an attic fan with a thermostat, but with the high heat these past weeks, the outdoor temperature is often above the thermostat setting. Thus, I'm just replacing all the air in the attic with ...
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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 ...
4
votes
2answers
9k views

Workarounds for single-zone HVAC? Second thermostat? Adjust vents?

I have a two story brick home built in 1970 with a relatively new HVAC system blowing through original ductwork. In the summer its too hot upstairs and too cold downstairs. I know that the full ...
4
votes
1answer
144 views

Is it possible - setting thermostat based on a seperate thermometer

I'm looking into building a solar water heater, but I'm wondering, is it possible (and what products should I be looking for) to turn on a pump when the water in the solar heating device is hotter ...
4
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1answer
4k views

Replace two-wire thermostat

I'm replacing an old mercury thermostat with a digital one. The new unit has 7-8 connections (labeled w1,wh,r1,rh,y,c, etc.) and a bunch of instructions about how to connect similarly labeled ...
5
votes
2answers
12k views

Should I use 12/2 or 12/3 to wire a 220V electric baseboard heater and thermostat?

When I bought my baseboard heaters, thermostats and 220V breakers I was advised to get 12/3 wire. When I attempted to install the heaters I found that the thermostats, heaters, and even breakers have ...
0
votes
1answer
362 views

Does a fridge thermostat need a ground connection?

I've recently replaced the thermostat in my fridge with a new unit with a much higher temperature range (this unit specifically). The unit I took out had a ground connector & the original wiring ...
4
votes
4answers
3k views

What would cause a clothes dryers thermal cutoff to keep tripping?

I have Kenmore dryer model 110.96588210. For about 10 years it worked flawlessly. Then, its thermal cutoff started blowing in an unreasonable frequency. Since the hi-limit thermostat must be replaced ...
3
votes
3answers
4k views

Why won't my AC system turn off after I flipped the breaker?

We've got a central cooling air conditioner that was installed in 1984 with a thermostat from that same year. We are replacing the thermostat with a new programmable one (which has a 100% ...
2
votes
2answers
3k views

How can I tell what kind of heating system I have?

Seems like a simple question, but I've had a very hard time finding a definitive answer to this. I went to the hardware store to buy a replacement for a faulty thermostat and when I arrived and ...
3
votes
1answer
122 views

How come the temperature is sometimes not maintained?

First let me come right out and say that I am a software guy and this seems like a hardware problem, so I already feel out of my league. That said, here's the deal: Background: I have two-zone "hot ...
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vote
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 ...
2
votes
1answer
243 views

HVAC electric thermostat panel “goes dead” and then live again all the time

I have this digital thermostat controlling my heater (gas). When I turn it on to lets say 66 deg, and the house is at 60, the HVAC will start working of course. Problem: After few minutes, the ...
2
votes
1answer
858 views

What is causing the high limit switch to pop on my electric water heater?

The high limit switch has popped twice on my electric water heater, both times at night. I reset the switch and the water heats and it's ok throughout the day. Wake up in the morning and it's ...
4
votes
1answer
1k views

What's wrong with my thermostat (fan / limit control)?

I previously asked about wiring the White-Rodgers fan/limit control on my wood stove. It's now wired and the wood stove is fired up. I ran the fan wires to the fan (hot) and I capped the limit ...
3
votes
1answer
6k views

How should I wire this White-Rodgers fan and limit control? What about the thermostat?

I have a wood-burning stove, that is used as an auxiliary heat source in the house. There's a regular electric furnace, and adjacent to it is the stove. The warm air duct (out) from the stove ...
3
votes
2answers
6k views

Why does the gas furnace blow cold air at the start of the heating cycle?

What does this problem sound like? There is a 25 year old gas furnace in the house we rent. (The guy that owns the place claims there is NO problem at all. He said the igniter is brand new and ...
3
votes
1answer
591 views

How do I properly wire a 5-wire thermostat? What is this ambiguous '4' label?

I took the old thermostat off, and had G,Y,W,Rc and '4' terminals connected to the Green, Yellow, White, Red and Black wires respectively. Voltage from Rc to G|Y|W was 24VAC as well '4' to G|Y|W ...