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
143 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
169 views

Switching from multiple thermostats to a single one

I have a heating system that has a separate "smart" heater in each room, each controlled with a separate thermostat (a simple one, like Honeywell T410A1013). What I would like to do is to convert to a ...
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1answer
396 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
279 views

Why isn't my thermostat working?

I have an old Lennox (gas heat only) thermostat. There are 3 wires coming from the wall. Black, yellow and a light blue color (could be a faded green or an old dirty white). The thermostat wouldn't ...
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1answer
491 views

Connection for C wire on Mastertrol Mark V zone control panel

I have spent hours searching the web for information on this 20+ year old zone control panel, which supports 3 zones of Heat and A/C. The thermostat I'm replacing (on Zone 3) connects to T4/T5/T6 as ...
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1answer
902 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
2k views

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

I Purchased the Honeywell WiFi Prog Thermostat to replace my Round Digital Honeywell Thermostat. I have separate Heating and Cooling (Heating is a Weil McLain Boiler for Hot water baseboard and Hot ...
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1answer
122 views

Is there a way to make a thermostat based heating system more accurate through either adding probes or hacking?

In my Brooklyn apartment, heated via steam radiator, my thermostat is in the unheated hallway between all the rooms. The temperature it reads is often different, than both the rooms with heaters and ...
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0answers
172 views

Why isn't water running through our radiators?

We had a plumber in today to bleed our rads. He also changed the batteries on the thermostat and fiddled around with the boiler. Since he left the temperature has dropped dramatically and he's refused ...
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1answer
295 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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1answer
805 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
860 views

Is voltage too high in C wire going to thermostat?

I've managed to add a C wire to my thermostat. I then decided to check the voltage between the R and C wires, and find that it read as 27.8 volts, not the 24 volts it was supposed to be. Could this ...
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1answer
294 views

How do I turn off the power to my programable thermostat?

I am installing a new programable thermostat. In trying to cut power to the old one I have tried a couple of things but not sure I have done enough to cut all power. One, I shut off the furnace ...
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2answers
4k views

Are there any ductless mini split systems that offer standard HVAC wiring controls?

Have been looking for in the US a ductless mini split heat pump system something like the Mitsubishi Electric Mr. Slim that uses a non proprietary wiring scheme for its wall mounted thermostats. ...
2
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0answers
186 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 ...
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1answer
226 views

How can I replace a 4-wire manual thermostat with a programmable thermostat?

I"m replacing a 4-wire manual baseboard thermostat with a programmable SBFT2W thermostat. After connecting the wires, there are two lead wires from the old stat that are still unconnected. They are ...
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1answer
814 views

why won't my furnace turn off once it reaches the desired temperature

I have a moncrief furnace and replaced the thermostat but the furnace will not cut off once it reaches the desired temperature. What could be wrong?
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3answers
10k views

How to wire multiple thermostats

I would like to have two thermostats controlling a single furnace. However I'm not 100% sure how I would need to wire everything to achieve the correct effect. Assuming a thermostat simply acts like ...
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2answers
3k views

Why is my A/C unit running when the heater runs?

So it finally got cold here in AZ. We switched our thermostat from A/C to Heat. Now for some reason when the electric heater runs, the A/C condenser unit outside kicks on too. This is our first winter ...
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2answers
184 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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0answers
49 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
425 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. ...
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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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2answers
3k views

Should my thermostat's blue wire be going to W2?

I've recently moved into my first house and am looking to replace the existing basic thermostat in the home. Here is a picture of how I found it wired: Researching the wires, I've read that ...
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2answers
690 views

Using a solar system with a condensing boiler for the central heating instead of tap-water?

According to the manual of my AWB ThermoMaster 2HR 28.02WT Condensing boiler, it is compatible with a pre-heating solar system for tap-water only. It even has extra facilities to ensure that the ...
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1answer
10k 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
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 ...
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1answer
576 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
3k 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
713 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
1k 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
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4answers
736 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 ...
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1answer
141 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 ...
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5answers
18k 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 ...
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2answers
1k 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
286 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
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2answers
1k views

Trying to wire a 220v line-voltage thermostat

I am trying to replace my old 220v 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 ...
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2answers
880 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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1answer
549 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
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1answer
308 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
5k 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
100k 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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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
998 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
731 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
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1answer
127 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
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2answers
1k 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
474 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 ...