0
votes
0answers
28 views

Thermostat replacement

My old thermostat is a carrier t-stat and has a jumper wire between o/w2* and L I am upgrading to a honeywell wifi t-stat, should I install the same jumper wire on the new thermostat? I have an ...
1
vote
1answer
26 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 ...
0
votes
1answer
29 views

air conditioning system stays on even when we turn off our thermostat

Our A/C system stays on even when we turn off our thermostat. What should we do to try to fix it?
0
votes
1answer
53 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 ...
0
votes
1answer
97 views

why does my heat pump wiring diagram show 7 wires going to the thermostat but the thermostat only says it needs 5?

Here is a link to the wiring diagram for my heat pump. The thermostat that I am planning on buying has the following terminals C, G, Y, O/B, RC, R, Aux, E, and L. The instructions say to jump the RC ...
0
votes
0answers
53 views

Why is my heat not shutting off at the set temperature?

When I turn the heat on on my central heat and air unit, the heat came on then continued to run getting really hot. It would not shut off unless I turned from auto to on then back. Sometimes I had to ...
1
vote
2answers
128 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. ...
1
vote
2answers
527 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 ...
0
votes
1answer
592 views

Need help running and connecting a 'C' wire to my new thermostat

I have a Laars gas boiler that has 3 heating zones; basement, 1st floor, and 2nd floor. I want to replace the old mercury honeywell tstats on the 1st and 2nd floor with newer honeywell RTH9580 wifi ...
0
votes
2answers
1k views

How can I modify a 4 wire thermostat to a new thermostat requiring c wire?

I attempted to replace my thermostat with a fancy new Trane z-wave enabled model. To my dismay my home was only wired with a 4 wire setup with no 5 hidden in the bundle. I followed Insx on the web ...
1
vote
2answers
1k 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 ...
4
votes
1answer
193 views

How can I determine if my HVAC system has features which are not currently wired to my thermostat?

I recently upgraded to a Nest Thermostat. This new thermostat supports many more terminals and features than my previous thermostat. My old thermostat had the basic terminals; G,R,C,Y, and W. I am ...
1
vote
3answers
90 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?
0
votes
1answer
2k views

Wireless Thermostat C-Wire Substitute

I've read How can I add a "C" wire to my thermostat? and checked out the Venstar Add-A-Wire Accessory. I've watched Honeywell's YouTube video on "DIY Wi-Fi Thermostat Substitute G-Wire for C-Wire," ...
0
votes
1answer
282 views

No electricity going to thermostat

Our old thermostat is working but I want to change to a new one (nest thermostat). I have two exact HVAC unit at home. I change one it works but when I change the second one it doesn't work because ...
3
votes
2answers
511 views

Can I use an unused wire as a “C” wire?

I just bought a new thermostat that is Wi-Fi enabled and it requires connection to a "C" wire. The old thermostat does not have one running to it, but there are other unused wires. The thermostat ...
1
vote
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 ...
0
votes
1answer
2k views

How do I add a C/ Common wire to my “Specific” HVAC system? [duplicate]

I just bought a new WiFi thermostat that requires me to add a C-Wire at the furnace. I have read the questions related to my issue but would like a suggestion on my particular (incredibly OLD) ...
0
votes
1answer
283 views

Thermostat C-wire replacement using a wall socket?

I have a Filtrete 3M WiFi thermostat. As expected, it takes a C wire, which my apartment doesn't have and the apartment maintenance folks wont' let met wire either. However, there's a wall socket ...
1
vote
1answer
501 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 ...
0
votes
1answer
307 views

How can I add a C-wire to a Venstar T5800 thermostat?

I am trying to replace my existing thermostat. My old thermostat has: Rh, W (coming from the heating unit). Rc, Y, G (coming from the AC unit). On the Venstar T5800, I can map as follows: Rh+Rc ...
11
votes
2answers
7k views

Why is my Nest thermostat not working with A/C?

I installed Nest thermostat a few weeks ago, replacing an old Lux programmable thermostat (there was nothing wrong with it). I connected 4 wires (R,W,Y and G) to the Nest. But as soon as I'd ...
1
vote
0answers
82 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. ...
0
votes
1answer
315 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 ...
4
votes
2answers
592 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 ...
1
vote
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 ...
0
votes
3answers
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 ...
0
votes
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 ...
3
votes
2answers
1k 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 ...
0
votes
1answer
385 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 ...
2
votes
2answers
5k 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. ...
0
votes
1answer
239 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 ...
-3
votes
1answer
824 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?
1
vote
0answers
50 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 ...
1
vote
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 ...
3
votes
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 ...
1
vote
1answer
15k 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 ...
3
votes
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 ...
2
votes
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 ...
1
vote
2answers
810 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 ...
2
votes
1answer
142 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
votes
1answer
299 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 ...
34
votes
4answers
118k 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 ...
1
vote
2answers
891 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 ...
1
vote
4answers
494 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
9k 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
628 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 ...
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 ...
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 ...