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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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1answer
3k views

Heater will not shut off when it reaches desired temperature

I am just noticing this running the heat. If I set the thermostat to 70 it will run and run and the temperature reads 70 but the unit does not shut off. If I turn it up to 72 and then when it reaches ...
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1answer
53 views

Is a 4000W line voltage thermostat sufficient here?

I want to upgrade a baseboard electric thermostat to a programmable. The existing digital, non-programmable thermostat is rated for 22A (5280W) (made by PSG). The only programmables I can find max out ...
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1answer
30 views

Can a Thermostat Common Wire (C-Wire) Be Added to a DNV40NB Heater?

During recent renovations, we had to move our existing thermostat. Instead of replacing it with the same dumb 2-wire knob (white/red), I'd like to get a smart thermostat like the ecobee3. All of these ...
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0answers
588 views

How to insulate a thermostat

Some previous owner of my home moved the original round 2-wire thermostat to a wall of the vertical chase used for the hot water heater vent, the gas lines, etc. The wall is quite a bit colder than ...
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3answers
91 views

Thermostatic Control of Simple Apartment Heater

My daughter's apartment has a very simple heater. As shown in the pictures below, it is an heater-coil unit with only a fan control. There is no temperature control or thermostatic feedback. So, for ...
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0answers
3k views

Honeywell RTH6500 WiFi Thermostat wiring questions for a heat pump

I'm trying to install a new Honeywell RTH6500 thermostat on an old heat pump system that has regular plus emergency heat and the closest matching diagram says to put both the white "W2" wire and black ...
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2answers
262 views

Box Fill for Line Voltage Thermostat

I know that normally a receptacle or device in the gang box counts as 2 conductor volumes. Does a line voltage thermostat just count the same as any other device? I'm replacing an old mechanical 240V ...
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1answer
56 views

Fuel oil burner running intermittently

Fuel oil (Beckett oil burner) here. It's -20°F outside right now and the house is at 61°F even though I have the thermostat cranked up to 75°F (we have a thermometer in the house as well, ...
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2answers
53 views

Help with Sain Smart 24V Relay Cycle Timer Module

I'm considering getting one of these: https://www.sainsmart.com/products/24v-relay-cycle-timer-module ...to force my 2nd floor thermostat to force heat on every so often (say, 1 minute every 15) to "...
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0answers
752 views

Need Help on Adding a Common Wire for Nest

I recently purchased a Nest thermostat. After couple weeks of usage, the Nest is constantly shut down due to low battery. I search online that adding a common wire is the go solution for this. However,...
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1answer
97 views

Ecobee3 lite connected to Lennox Pulse G14Q Heat/Air Condition

I have read a similar wifi thermo connection feed here and they had success hooking the C wire to the T terminal on the furnace. I can get power to run the thermo from the T terminal, but when I do, ...
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2answers
199 views

Why would furnace not come on immediately?

I had a brief scare just now. It is 7-degrees right now and getting colder so I definitely don't want a furnace failure. I came home and house was at 62 with thermostat at 64 (my standard not-at-home ...
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1answer
156 views

Ecobee3 Setup and furnace only has W G R

My existing thermostat has 4 wires (missing C) so I'm attempting to use the Power Extender Kit (PEK) at the furnace control board. Only problem is, I only have 3 wires that are obviously labelled at ...
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1answer
850 views

How often to replace thermostatic mixing valve

To start off, I absolutely hate idea behind thermostatic mixing valve, but that's not a question. The water in my house runs hot for about 10 minutes and then turns icy cold, and I have to turn it ...
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3answers
433 views

Why is the furnace heating the house far past the thermostat setting

Problem: Furnace came on as usual in the morning but failed to shut off after the set temp on the thermostat was reached. The house temp (as measured on the thermostat) reached about 10 degrees higher ...
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2answers
96 views

Upgrading baseboard thermostat -wiring help

Going from old analog thermostats to programmable digital. They're all 240v but appear to currently be wired as single pole and new stats are double. Photos attached of line in, and two out for load- ...
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1answer
304 views

Upgrading 2-wire to Ecebee3

I have a honeywell 2 wire thermostat (old) that has 2 wires R W that seem to be wired directly to the furnace (blower/burner??) but I also have a control board with no wires attached to it. I tried ...
5
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1answer
155 views

Adding a C wire to older 3 wire

How do I use the green wire as a C wire as suggested in most installation instructions for the newer wi-fi thermostats? They all reference terminal strips at the furnace, all I have is the 3 wire ...
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0answers
693 views

Thermostat won't display temperature and won't control heater (although fan works)

I'm having issues with my Honeywell RTH7600D thermostat. It's a couple of years old and has worked fine until recently. We're in Southern California and the cold weather has recently started so I ...
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2answers
909 views

Can I use the Y wire in place of the C wire for my new thermostat?

I'm looking to wire a Honeywell Lyric T5 to my furnace (I do not have an air conditioner, I do have a humidistat). My current wiring at the thermostat is G,W,Y,R. At the furnace it's G,R,C, and 2 at W,...
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1answer
54 views

Rapid on/off cycling of furnace

My 50-year old wall furnace keeps cycling on and off as it gets near the set temperature. Can I fix this by changing to a new thermostat? It's a 2-conductor cable (no blower).
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1answer
2k views

Thermostat won't always start heater on its own

I have a gas furnace that seems to work fine; it keeps the house warm when things are running as expected. Sometimes, however, we'll notice the house is getting cold. The temperature on the ...
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1answer
323 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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0answers
42 views

furnace wont kick in

My furnace seems to work intermittently. overnight its seems to stop... i have checked the thermostat and it shows says it is heating. fan is on auto, but nothing coming out. when i turn heat to off, ...
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2answers
135 views

How to check thermostat is working?

This is the wiring of my Honeywell T8411R. I noticed my room was not warming up. I moved the switch to Em.Heat and still no warm air blowing in ducts. I would like to test if my thermostat is sending ...
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2answers
983 views

Pulling wire using previous wire?

I’m trying to pull a new thermostat wire down from a first floor room down into the basement. The exit point in the basement is in the ceiling, between two ceiling boards pretty inaccessible. Would it ...
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0answers
1k views

fireplace thermostat will turn off fireplace but won't turn it on

I have a propane fireplace that wouldn't start. Cleaned the thermopile and thermocouple and got the pilot to work fine. Then the main burner wouldn't light from the thermostat--it only lit if I jumped ...
2
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1answer
188 views

Where to connect c wire

I’m installing a new WiFi thermostat that needs the c wire. I ended up running new thermostat wires that contained the common wire but now I’m stuck on where to connect it to the furnace. Can ...
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1answer
5k views

Why are the white and orange wires both connected to my thermostat's W terminal?

I wanted to get a programmable thermostat, but when I look at the wiring of the existing thermostat I’m not sure why the white and orange wires are both going to the W terminal. Other thermostat ...
2
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1answer
6k views

Ecobee3 not turning on heat, but fan is on

I have an Ecobee3 that has been successfully working (both heat, fan, and AC) for the past 6 months. Recently I was trying to get my humidifier working so I was playing around with some wires, which ...
0
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1answer
44 views

UV Lamp on heating system?

I have a Honeywell thermostat & keeps on flashing "change UV Lamp" Where would I find the UV lamp installed in the system, & how do I replace it?
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1answer
446 views

C Wire for Thermostat

I am upgrading my thermostat (Have AC & Heat) and found that it doesn't have the "C" wire that I need to power my new thermostat. The furnace does have a terminal for C, but only condensation pump ...
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1answer
315 views

Removing a room stat from central heating (in order to fit Hive)

I'm about to fit a Hive wireless thermostat to my central heating system and have a couple of questions. I need to disconnect the existing room stat - a Horstmann Centaurstat 7 - as this will be ...
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1answer
316 views

Installing a Hive Thermostat

I purchased a HIVE thermostat and want some assurance before I go about installing this. First of all i was wondering where to put the receiver as I thought it would just replace one of the ...
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1answer
67 views

Proper placement of thermostat [closed]

I am building a new home and the question of where the thermostat for the upstairs should go has risen. It was originally wired to be place in my daughter's bedroom but I had requested that it be ...
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1answer
163 views

How to connect wifi thermostat with a boiler after cable upgrade?

I have an old battery operated thermostat right now with two wires (18/2) attached to it running to a boiler. No AC, fan, etc.-- just a boiler. I can easily replace the wire with 18/5 one, however I'm ...
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2answers
4k views

Why do I have to tell my Nest thermostat to either cool or heat my house?

I just moved into a house with a Nest thermostat and this is the first time I've ever had a thermostat of any kind (just had window units and radiators for the past 20 years). I don't understand why ...
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3answers
2k views

Circuit to make Nest thermostat think there are separate heating and cooling systems

I have a Nest thermostat that I am trying to wire in a simple but unique configuration. My apartment uses fan coil units for heating and cooling. The building changes over from hot to cold water for ...
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1answer
44 views

My thermostat and heating system was working fine but the batteries read low power

So my Honeywell non WiFi Thermostat was working fine except for the low battery signal in the top right-hand corner. We took the face off of the thermostat of course shutting the Heat and fan off ...
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1answer
322 views

Help with smart thermostat wiring

Installing an ecobee4 thermostat. Have a 2 stage furnace with ac. Had a Trane furnace installed couple years ago and just noticed it's jumpered between W1-W2. Old thermostat wire was only 4, ...
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1answer
56 views

Problems with my thermostat

My thermostat will turn on the baseboard electric heater but will keep running till you turn it all the way off.
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1answer
750 views

How do I get the Nest Thermostat to warm up my house prior to arrival

I have a Nest Thermostat and live in the UK. I have a radiator based heating system. When I leave the house, some time later the Nest realises this and sets my house to Away. From this point onwards ...
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1answer
227 views

WiFi Thermostat - C Wire

I am trying to install an Ecobee 3 thermostat to replace the upstairs one I have now but the 3rd wire isn't connected to anything on either end. I added the basement thermostat just to complete the ...
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2answers
104 views

How can I control my furnace blower independently from the furnace itself?

I have an outdoor wood burner with a water jacket. It has an electric blower that needs to run to get the fire going hot enough to be clean burning. I have a 200 gallon storage tank, and plan to ...
2
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0answers
622 views

Honeywell WiFi thermostat jumper loop separate ac and gas furnace

I need to validate my understanding for the installation of a WiFi thermostat that requires 24volt continuous power to operate in a constant state. I am DIYer who is computer literate. Like a number ...
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1answer
256 views

Replacing thermostat on Sanyo mini split

I have an old Sanyo KMH 0922 mini split. The air conditioning seems to work OK. Last winter on heat it was either on or off the thermostat wouldn't control the temperature correctly. This ...
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1answer
829 views

Honeywell thermostat oozing yellow and programing not working

I installed a Honeywell thermostat last year for our boiler and it worked perfectly. This year we were having issues with it not following the program schedule. The thermostat should be sleeping and ...
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0answers
325 views

NEST thermostat for hydronic floor heating: the three wire setup

I'm trying to install a 2nd generation Nest thermostat for my hydronic floors. So it's only meant for heating and not for cooling. Someone else removed the old thermostat a long time ago so I don't ...
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1answer
723 views

UK Nest Installation - Underfloor heating including floor temperature sensor/cutoff

I would like to use Google Nest with my underfloor heating system which is under a wooden floor. Other thermostats allow the user of a floor sensor which monitors the surface temperature of the floor ...
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1answer
261 views

Replacing old mechanical line voltage thermostat with Caleo from Casa Connect

------ Update ------ I followed the instructions from Casa: I made A1 go into the new thermostat and then out into the blacks of B1 and C1 (see my diagram of the old setup below). Then I connected A2 ...