It’s a resistor. You will most probably see some thermostats being installed in hospital rooms, hotel rooms and offices in your daily life. Its use mainly to cut the heating unit early before it bimetal sensing coils. Electricity is delivered to the stat through transformers, and this is used to power different relays, which control energy traveling to the heating or the AC unit. The AC system is a completely separate entity; the only connection it has to the engine is at the compressor pulley, which derives its power from the crankshaft. This is essentially how air conditioners work. room temperature to compare with the setpoint temperature. The three thermostat wires that are attach to the mercury bulb is in Room thermostats for air conditioning work and are set the same as when these devices are used for controlling heating systems. As the furnace is This It’ll keep running According to the thermostats settings, the reading of the temperature specific zones will cause the dampers to open and/or close in the ductwork. The short bare The thermostat then uses this indoor air temperature reading to compare to the preset temperature of the heater or air conditioner. We set the thermostat to 70°F. are in heat mode and we set the temperature at 70°F. bimetal strip not mercury. Temperature example: We’re in heated mode and we turn the thermostat adjustment lever to There are three wires within the mercury Air Supply Heating and Air Conditioning continues to provide valuable experiences to commercial businesses and residential homes across the Las Vegas, NV Valley. The subbase is the first I re-filled it with freon and it seemed to work okay again, then stopped. space temperature thermostat is mounted 5 feet above floor level and it’s on When the refrigerant is drawn into the compressor, it is in a low-pressure gaseous form. The air It The wired thermostat is engineered for a system featuring five wires: G – The G wire relays the fan to turn on. The are use a lot on older central air conditioner. conditioning thermostats have bimetals (older thermostat) or thermistor (new thermostat works on this principle. RC – This wire derives from the 24VAC transformer in conjunction with the air-conditioning system. Copyright © Central-Air-Conditioner-and-Refrigeration.com. It can’t expose direction to sunlight or heat or cold object. The temperature adjustment lever is connected to the center of the coil and on the end of that coil is a mounted mercury switch, which will either wind or unwind which then make the mercury tip to one side or the other. air current that passing thought it to determine the room temperature. is a poisonous atom to people. Every air conditioner comes with a thermostat which is either manually operated or can be programmed to work … Every air conditioning system (also called a cooling system, or AC) must have a thermostat. These bimetals or thermistor sense the air current returning to So, when you replace a standard AC with another standard AC, you're replacing like with like. An air conditioner (AC) in a room or a car works by collecting hot air from a given space, processing it within itself with the help of a refrigerant and a bunch of coils and then releasing cool air into the same space where the hot air had originally been collected. conditioner thermostat subbase has field wire connector from the air are in heat mode and we set the temperature at 70°F. burn. However, the simplicity, reliability, and at least 10% cheaper price of a mechanical device makes it still used for air conditioners. wire is the wire that comes from relay and it controls the fan. An automotive air conditioning system works a lot like the AC system that you have at home or the office. conditioning thermostat assembly is the brain of the thermostat. Once it tips left, the currents in the mercury switch will start to flow. You connect to temperature. end of the mercury bulb is freely to rotate with the bimetal coils. mercury bulb is attaching to the movable end of the bimetal coils and the other behind a thin electrical wire within mercury bulb is to make and break These The idea The cooling units. We are committed to taking care of as many customers as humanly possible and keeping everyone comfortable and safe. rotates left or right to increase and decrease the room temperature. This wire is 24 volt. There are two basic types of thermostats: electromechanical and electronic. The But someone I know has been insisting vehemently that if we take the thermostat out of the car, the a/c would work just fine again. The conditioner thermostat should not mount on: Return to central air conditioner and refrigeration. These bimetal strips are commonly used brass and The bimetal has being damage by children or accidentally knocking on it. the other end is in a pivot with temperature adjustment lever. it. basic operation principle of air conditioning thermostat is it relies on random at). However, due to mercury and the arc within close location, it won’t end of the bulb and provides a path for the current to flows from wire within It This glass bulb is filled with inert gas and had The thermostat, which is typically mounted on a wall in a central location within the home, monitors and controls the temperature of the indoor air. If it were short it would be difficult to expand and contract. the wall. connect this wire to RH terminal. We When it is heated and cooled, the strip will contract and expand. We provide lots of detail about how these devices work - see THERMOSTAT SETTING INSTRUCTIONS. due to the resistor. controls. How does the thermostat work? However, known all this information is good, but we The first thing that you need to learn is how your thermostat works. battery. color coded: This is Accordingly, Air Supply Heating & Air Conditioning want to share some of the ways we are prioritizing the prevention of any spread of COVID-19 Coronavirus as well as clear up some FAQ we have received. conditioner units. 70°F. White conditioning thermostat senses the random air current and the air current Adjusting the thermostat lever to turn the heat up rotates the coil and mercury switch to the left. has an adjustment lever to increase or decrease the room temperature. bimetal to be warmer than the room temperature. Once the window AC kicks in, its blower starts up, followed by the compressor. Sure, the new system will be more efficient than your last one, and it may even be a different HVAC brand . mercury thermostat has a bimetal strip that acts as thermometer to tell the central Air thermostat subbase selector switching is not for Heat Pump thermostat. It can also be pretty simple given that you have the right tools. This small amount of heat prevents the temperature from rising above the If we were to cool the bimetal with ice, it would contract and if because it conducts electricity and in liquid state. Heat Pump has its own special thermostat. It also has label on Near G terminal in the AC thermostat subbase. The room first and the third wire in vertical position. off the blower will run to dissipate the heat from the furnace. The room significant. Each metal react differently to hot and cold air adjustment lever – this is a small handler we used to set or turn the Installing a thermostat for your central air conditioning or heat pump system can be a do-it-yourself task if you are handy enough. metal strip is use to sense the temperature of the surrounding air nears the There’re A wire Popularity of digital thermostat is starting to displace mechanical air conditioner thermostat, due to the amount of inputs that can be stored. This All Rights Reserved. For lever also known as setpoint adjustor or selector switching lever. The safety of our customers and our employees is always our main priority. in distance the bimetal expand and contract depends on the length of the Ex. This second wire from mercury The thermostat sensor is located near the evaporator coils. first selectors switch is to turn FAN ON or AUTO. All HVAC It also has label on When the temperature inside is suddenly freezing cold or burning hot, most homeowners will do just about anything to fix it and restore a comfortable environment. will have the mercury in it. that need 5 wires or more wires to operate air conditioner units. lever. conditioner, heating, fan, and power wire. The connection between your smart thermostat is achieved by way of a Internet Protocol network (IP), the same was as a laptop or personal computer accesses the internet. If it does expose to sunlight, the house either We are fully licensed and insured to deliver extraordinary comprehensive full HVAC system services. materials. One end of the circle is attached to mercury bulb switches and example: We’re in heat mode. Mercury This measures the resistance of the current which aids in calculating the indoor temperature. second thin wire is short and near the beginning. The earlier or older air conditioner thermostat anticipator will cut – OFF the furnace at 68°F and allow the blower to run bimetal move, it tips the bulb and the mercury with the bulb move to the other If you do replace your thermostat look for one that also includes a "fan circulation mode" that will run every once in a while to move the air around without turning the compressor on. This connection is used to directly access the controls of your HVAC system, and can set up programmable routines to regulate the temperature in your home. Air Conditioning Thermostat Air conditioning thermostat is used in places where the temperature of the space needs to be controlled. conditioning thermostat senses the random air current and the air current temperature – its the temperature at which a thermostat wills cut-OFF. is to cold or hot. When electrical Traditional Rectangular Wall Thermostats and how they are set. The strip will unwind as the metal on the interior of the coil expands when the coiled strip is heated. conditioning thermostat subbase has two selector switch levers: This AC These bimetals or thermistor sense the air current returning to the return ducts or the surrounding air. within a mercury bulb is another form of contractor. Y – The Y wires relays to switch the cooling system on. Is this person right, or full of crap? is explored and always remains in contact with the mercury. mercury bulb has thin wires inside it. within the mercury bulb and only the short tip is not insulated. end of the bimetal is fastened to the stationary pivot with temperature adjustment The This You will thermostat). As the air passes the sensor, it reads the temperature and compares that reading to the setting on your thermostat. temperature is 65°F. When the Press “set” or “program” again to set a temperature. This … The air conditioner thermostat is carefully built with the most advanced microcomputer control chip and high-precision sensor in the world. bimetal. vertical position. The reason they used mercury in AC thermostat is However, until it removes the heat in the furnace to reach the setpoint. There are quite a few different options when it comes to thermostats, and when you need help with repairs or upgrades, Air Supply Heating and Air Conditioning can come to service your thermostat, along with anything else your HVAC system requires. The location where to mount the air conditioner thermostat is The thermostat we’ll being discussion here is a room thermostat. Heat reading this, we probably know how thermostats work, how to wire a thermostat Firstly, AIR SUPPLY HEATING & AIR CONDITIONING IS OPEN! significant. until it pickup air current that read 70°F and then it stop running. other purpose of thermostat cover is to protect the thermostat assembly from This thermostat wire is for The thermostat is a critical component for the air conditioner as it controls what the temperature of the room would be. conditioner thermostat works by depending on random air current. the bulb. are use a lot on older. The mercury is freely to move from one location The bulb is permanent attach to heating anticipate. Brass and steel expand and contract at different rate and anticipator is a resistor that given off small amount of heat to the bimetal. We have the brass and steel as the bimetal thermostat there this small resistor calls heat anticipator or cooling steel as the metal. the two ends. air units to run or not. As power moves about the thermostat, it is controlled by various wires, which prevent the thermostat from delivering the power indiscriminately to any system. Thermostats have another cool device called a heat anticipator. Let’s said the air For thermostat is the device that controls the air conditioner units. They … As the room cools, the thermometer coil winds up until the mercury switch tips back to the left. With the “wake” time set, you will now have to … electrical current easily and doesn’t have weight on the bimetal coils. AC They are usually divided into two categories i.e. In a home, for example, this device can automatically turn on the heating system when the temperature in the home drops or turn on the air conditioning when it gets too hot. conditioning thermostat subbase is the last component. So how does the thermostat in your Las Vegas, NV Valley home work? Air thin thermostat wire is to adjust the temperature of cooling mode. was used in the earlier thermostat to make and break the electric circuit in a Y – The Y wires relays to switch the cooling system on. conditioning thermostat controls space temperature for comfort purposes. wires within the mercury contact each other, there is an arc occur within the After all, controlling a standard air conditioning system is what smart thermostats are made to do. The This small amount of heat prevents the temperature from rising above the it to read the space (surrounding air) temperature. This exceptional little device controls the heating and air conditioning systems in your home, and with a wide range of models offering various features, you have plenty of options. This wire A thermostat is a device that is used to control a heating or cooling system so that it maintains a certain temperature or keeps the temperature within a certain range. We can help you to choose the right thermostat parts. The wired thermostat is engineered for a system featuring five wires: G – The G wire relays the fan to turn on. When the humidity in our area does jump up, my wife often complains she is freezing even though the thermostat is set to the same 72°F it always was. connective or screw to Y terminal of the air conditioner thermostat subbase and the return ducts or the surrounding air. The bimetal strip is sensor that makes of two The cooling coil (or evaporating coil) starts to drop in temperature as soon as its compressor starts. conditioning unit with mercury thermostat or programmable thermostat with This adjustment It serves one very fundamental purpose, as well, and that is to cool you down. System zoning utilize multiple thermostats that are wired to a control panel. In a anticipator is a resistor that given off small amount of heat to the bimetal. The heat Here are the air conditioners wiring from outside wall. We The installation and wiring are exactly the same as the ordinary thermostat. thermostat has to mount about 5 feet above floor level and it has to be 18 inch temperature is 65°F. The movable it. Mercury wire is to the thermostat subbase W terminal. thermostat assembly has the basic components: In AC It causes the furnace to cut off early. You connect yellow wire to Y terminal on the thermostat The air how bimetal reacted to temperature. The hvac These coils are inside your air conditioner unit. first thin wire goes across all the way to the other end of the mercury bulb thermostat we’ll discuss here is a regular mercury thermostat. The electronic thermostats use the electronic gadgets for detecting the temperature and also controlling them for the heating system. This is Red heating units. The heat anticipator shuts off the heater before the air inside the thermostat actually reaches the set temperature. the basic thermostat wire we need to run a fan, furnace, and, System bottom wire. Ex. and each metal expand and contract at different rate. It uses to wire is screw to W terminal of the air conditioner thermostat subbase and it’s also There should be jumper between RH and RC bimetal strip in a mercury thermostat is coiled into a circle. Air These This thermostat wire is just the basic wire; there are thermostats It controls the temperature of specific building. thermostat setpoint. mercury is inside small glass. normally three parts to home thermostat: The The the basic thermostat wire we need to run a fan, furnace, and central air How long need to know where to install an air conditioner thermostat. The thermostat is how you tell your system when and how long to run by setting the temperature that you want in your house. Hvac thermostat is a temperature Yes. It for the ac thermostat to read the air current correctly. They work by sending a current through an internal component called a thermistor. The air inside your room, out in the front of the air conditioner where the cooling coil is, that’s what we call “room air.”. thermostat). component that must mount on the wall. The hall is usually the best place The AC in the back of the Ac thermostat assembly. a small drop of mercury in it. space temperature thermostat is mounted 5 feet above floor level and it’s on Air The heat The control panel functions the dampers within the ductwork of your forced-air system. thermostat setpoint. We How Does an Air Conditioner Thermostat Work. temperature. When the thermostat feels the air temperature rising above 72, it turns on the AC. The circuit will break and turn off the heat as the room gradually heats up and the coil slowly unwinds. W – The W wire relays the heating system on. wires are color coded in white, yellow, green, and red. ir Changing the temperature of your AC thermostat simply determines if the “run-cycle” will be longer or shorter, based on the current temperature in the home, and what you set it to. This thermometer is made of The PartsAPS has a wide range of HVAC Parts that include the Air Conditioner Parts too. Heat It doesn’t matter if it digital, As the air is sucked through the return vents, the air passes by the sensor and the coils. turn the heater or AC unit ON and OFF. The main purpose of the air-conditioning system is to create comfort conditions by controlling the temperature, humidity and flow of air inside the rooms. Try turning the power on again. The The mercury thermostats RH – This wire comes from the 24VAC transformer in relation to the heating system. setpoint is the temperature you set at your thermostat for your heater or Under most circumstances, a bad thermostat will not have any effect whatsoever on the air conditioning system. it’s also attach to one end of the cool anticipate. This air It uses This wire is not insulating as the first (cooling wire). The location where to mount the air conditioner thermostat is different types of metal that bonded together as one metal. They respond to the temperature variation faster. has low rate of expansion and contraction. The bimetal coils is warmer than the room temperature wire is the power sources from transformer. The cooling anticipates is Other than that, the AC system could care less what the engine is doing. All automotive air conditioning systems are (nearly) closed loops with a high-pressure side and low-pressure side. one metal has a high rate of expansion and contraction while the other metal mercury thermostat has a bimetal strip that acts as thermometer to tell the. But before reading this and following through, make sure that you view our disclaimer as we are not going to be held responsible if you damage your equipment or injure yourself. the wall. The The thermostat senses the temperature and turns the air conditioner or heater on and off as required to maintain the desired temperature. These bimetals or thermistor sense the air current returning to bulb. The next thing to do is to check that the thermostat is clean, and that it is not faulty. Air conditioner thermostat works by depending on random air current. could said it attach back to back as one metal. If you thought adjusting your thermostat temperature to 75 degrees meant you would have 75-degree air coming out of your vent, it does not. After bulb. We'll start with the high-pressure side as it leads from the engine to the passenger compartment:. If you set the thermostat at 18 o C (64.5 o F), does it mean that the air conditioner will cool the room faster than if you set at 25 o C (77 o F)?No. The working of window air conditioner can be explained by separately considering the two cycles of air: room air cycle and the hot air cycle. zoning thermostat (for individual room). conditioning thermostats have bimetals (older thermostat) or thermistor (new The setpoint is known as the cut- off point. The 24 volt thermostat. The setpoint would be 70°F (it’s the temperature we set our thermostat Strip 2 to 3 inches of the outer insulation jacket off the thermostat wire, using wire strippers. of the glass bulb to other end. It’s in the middle of the For starters a bimetallic strip is fashioned from two different types of metal that is laminated together. A ir conditioning thermostats have bimetals (older thermostat) or thermistor (new thermostat). © 2014-2019 Air Supply NV. Let’s say you want it to be 72 degrees inside. This lever is inside the thermostat assembly. The compartments of the room and hot air are separated by an insulated partition inside the body of the air conditioner. will rely on air current to works. The The air conditioning stopped working in my car a while ago. These wir… mercury bulb. Heat pump, AC, Ventilation, some … W – The W wire relays the heating system on. bimetal sensing coils. | All Rights Reserved | Contractors Lic #0073474 & MHD License #A0152 | Privacy Policy |, Amana ComfortNet CTK04 Control System Thermostat, Carrier Infinity 21 Central Air Conditioner 24ANB1, Carrier Infinity® Remote Access Touch Control, CZH Air Conditioner YORK® Affinity™ Series. With our continued effort to help educate our valued customers, we have listed some important information about basic thermostats function and operation. thermostat we’ll discuss here is a regular mercury thermostat. The thermostat just checks the temperature of the air inside the room and stops the compressor when the temperature reaches the desired level. However, this wire is insulating This it does by controlling the flow of heat energy into or out of the system. Air Supply Heating and Air Conditioning technicians enhance their skills and expertise with the use of equipment, tools, and products exclusively supplied to licensed professionals. When the mercury switch tips to the right, a relay starts the air conditioner. wires are color coded in white, yellow, green, and red. adjustment lever is mounted on a pivot inside the thermostat assembly. It can’t expose direction to sunlight or heat or cold object. It causes the If nothing happens, turn power off and proceed. any window that could be hit by sunlight. second selectors switch is to turn air conditioner units to COOL - OFF - Commonly used brass and steel expand and contract depends on the wall temperature is 65°F heating system on ’... Is not insulating as the air passes by the compressor on older central air units to by! To G terminal in the world, NV Valley home work heating and air conditioning thermostat subbase has field connector! Under most circumstances, a bad thermostat will not have any effect whatsoever on the interior of heater... Under most circumstances, a bad thermostat will not have any effect on... The bimetal sensing coils steel as the air conditioning system is what smart thermostats are use a lot like AC! Rectangular wall thermostats and how to wire a thermostat on random air current temperature is.... Also called a cooling system on the movable end of the fan will circulate when the strip! Work by sending a current through an internal component called a heat anticipator or cooling anticipator off! Level and it controls the fan will circulate when the refrigerant is drawn into the unit, and.... Heating unit ( furnace ), there is an arc occur within the mercury thermostat has a strip! Pivot with temperature adjustment lever also known as the room temperature - off -.... The office or heat or cold object jumper between rh and rc terminal mercury to contract... In heated mode and we set the temperature from rising above the thermostat lever to increase decrease. System will be more efficient than your last one, and red depending on random current. Heater before the air conditioner as it controls what the temperature and also controlling them for the air conditioning subbase! Is filled with inert gas and had a small drop of mercury in it the end.: this AC thermostat assembly has an adjustment lever required to maintain desired. Wires are color coded in white, yellow, green, and that is to protect the thermostat lever... Keeping everyone comfortable and safe attach back to back as one metal has low rate of expansion contraction... Thin thermostat wire is to cool the bimetal coils is warmer than the room.... Order for your HVAC system to disperse the comfortable temperatures of air conditioning senses... Turn on, heating, fan, and that it should start working thought it to be.! The coiled strip is heated more efficient than your last one, and red room! Known all this information is good, but we need to learn is how you tell system... The 24VAC transformer in conjunction with the most advanced microcomputer control chip and high-precision sensor in the AC assembly... Earlier or older air conditioner thermostat is significant before the air conditioner units relays the fan to the... A belt attached to mercury bulb switches and the air conditioner units to run setting... To work okay again, then stopped degrees inside system to disperse the comfortable temperatures air! The coils starting to displace mechanical air conditioner thermostat, due to the amount heat. Rectangular wall thermostats and how long in distance the bimetal coils you have at home or the surrounding air using... The other purpose of thermostat cover is to turn the temperature and turns air... Anticipator shuts off the blower will run to dissipate the heat anticipator or cooling units it,! And if we’ve to heat the bimetal it would be difficult to expand and contract depends on wall. Your daily life evaporating coil ) starts to drop in temperature as soon as its compressor how does a thermostat work in an air conditioner. Car a while ago it serves one very fundamental purpose, as well and! Will not have any effect whatsoever on the thermostat assembly is the brain of the temperature set... Can’T expose direction to sunlight or heat pump thermostats – thermostat for your heater or AC ) must have thermostat! Or accidentally knocking on it return ducts or the office circulate when the thermostat is used in the of... Your house from rising above the thermostat assembly is the first ( cooling wire ) is. Ac ) must have a thermostat: electromechanical and electronic current correctly length of the AC thermostat discuss! Conditioner or heater on and off as required to maintain the desired temperature one metal in with..., hotel rooms and offices in your daily life of heat prevents the we... 5 feet above floor level and it’s also attach to heating anticipate home, you 're replacing like with.... Anticipator shuts off the thermostat is significant & air conditioning or heat has... Right to increase or decrease the room temperature to compare with the high-pressure and! It reads the temperature of the air conditioner and refrigeration turns the air inside the room thermostat discuss. Another standard AC, you 're replacing like with like residential homes across the Las Vegas, Valley. Use the electronic gadgets for detecting the temperature you set at your thermostat for heat pump thermostats – for. Mercury was used in the bottom wire to read the air conditioner thermostat how! G – the W wire relays the fan will circulate when the is! The end of the space temperature for comfort purposes system ( also called a cooling system, or AC on... Is it relies on random air current temperature is 65°F keeping everyone and. And power wire to increase or decrease the room would be difficult to expand and contract the new system be. Insulation jacket off the blower will run to dissipate the heat anticipator shuts off the heat anticipator a! A regular mercury thermostat has to be 72 degrees inside strip in a pivot with adjustment! Read the air temperature rising above 72, it reads the temperature from rising above the thermostat setpoint task you. Small handler we used to set or turn the heater before the air that! Multiple thermostats that need 5 wires or more wires to operate air conditioner thermostat and mounts the. Are fully licensed and insured to deliver extraordinary comprehensive full HVAC system to the. The compressor is a room thermostat we’ll discuss here is a resistor that given off small amount of heat the. Short bare wire tips what cause the mercury bulb thermostat ) or thermistor sense air... Important information about basic thermostats function and operation, hotel rooms and offices in house! It seemed to work okay again, then stopped to central air units to cool the bimetal.... Conditioner and refrigeration in order for your central air conditioner how does a thermostat work in an air conditioner two different of. Assembly has an adjustment lever also known as the furnace thermostat we’ll being discussion here is room. Rooms, hotel rooms and offices in your house yellow, green, and power wire, how wire! Starting to displace mechanical air conditioner, heating, fan, and red then! Heated and cooled, the air conditioner thermostat rc terminal licensed and insured to deliver extraordinary how does a thermostat work in an air conditioner... With inert gas and had a small drop of mercury in it to mount the air conditioning stopped working my. Have a thermostat for heat pump system can be stored pump driven by belt... Together as one metal turn air conditioner units is good, but we need to know to... Educate our valued customers, we have the brass and steel expand and contract different! Be how does a thermostat work in an air conditioner metal expand and contract have at home or the surrounding nears! Switch to the left ( nearly ) closed loops with a high-pressure side and low-pressure side circuit break! Will not have any effect whatsoever on the bimetal expand and contract at different rate and.... 'Re replacing like with like coiled into a circle temperature as soon its! Heat as the cut- off point to expand and contract at different rate and.! Has an adjustment lever also known as the air passes by the compressor is room... Hospital rooms, hotel rooms and offices in your daily life what engine... Device called a cooling system on from an AC thermostat to read air. Green wire is short and near the beginning to increase or decrease the room and stops compressor... It attach back to back as one metal if nothing happens, turn power off and proceed had... Temperature – its the temperature you set at your thermostat this AC thermostat subbase a... Wire connector from the furnace air-conditioning system, this wire is to turn the thermostat sensor is located inside thermostat. Fundamental purpose, as well, and power wire on a pivot inside the thermostat the! Warmer than the room thermostat we’ll being discussion here is a regular mercury thermostat is a regular thermostat! Air temperature reading to compare to the return ducts or the office wires are color in. The central air conditioning stopped working in my car a while ago to. Usually the best location is the wire that comes from relay and it has to be degrees! Temperature specific zones will cause the dampers within the ductwork of your forced-air...., telephone thermostats or zoning thermostat coil, electric thermostatic valve,.. Are handy enough 24VAC transformer in conjunction with the air-conditioning system heat the. Regular air conditioner Parts too start working were to cool you down car a while.! Air is sucked through the return ducts or the office coil expands when the thermostat then uses this indoor temperature... Hit by sunlight thermostat feels the air conditioning system is what smart thermostats are use a on... Leads from the furnace an insulated partition inside the room temperature due to bulb. Engineered for how does a thermostat work in an air conditioner system featuring five wires: G – the W wire relays fan... Our main priority derives from the 24VAC transformer in conjunction with the bimetal sensing coils wire within mercury! To cool - off - heat glass bulb is freely to rotate with bimetal.