Function A pneumatic thermostat is a device that is linked to a heating system in a business or home setting according on the Dr. Fix It website. The thermostat can be set to react to a specific temperature, either causing an air conditioning units system to fire up or a heat to turn along. The thermostat creates this change because it is connected to a string of tubes, which might tell the temperature of the environment based on exactly how much pressure is contained in them. Air Conditioning Using an attached dial, a pneumatic thermostat can be set to keep a room as close to a specified temperature as possible. When a room is getting too hot, atmosphere pressure in the tubes connected into the thermostat will be greater. This will result in the air conditioning system to kick on, cooling the room back down to your specified temperature. At the point, the air pressure in the tubes will get back on normal and atmosphere conditioner will automatically kick off. Heating In the winter months, a pneumatic thermostat can control a home or businesses heating system in much exact way it would control an air conditioning equipment in the summertime. After specifying a temperature, the pneumatic thermostat will sense when a room gets too cold as atmosphere pressure in the connected tubes will dissolve. It will then flip the furnace to return the room as close to the specified original temperature as possible. Older thermostats were controlled by a machine called a thermometer coil nailers. Thermometer coils are constructed of bimetallic strips--two strips of metal attached with each. When the temperature goes up, metals expand but different metals expand according to our current rates. That creates the coil expand simply because heats up and contract when it cools. When it contracts enough, the coil bumps suitable switch which turns on the heater. Seeing that it expands, it moves away from the switch, turning out of the heating again. Bimetallic thermostats are large, bulky and still not very accurate, and already been largely replaced by digital thermostats. Digital thermostats use thermistors, special resistors which can sensitive to temperature changes. Most resistors resist the flow of electricity within a constant rate, but thermistors change since it is gets hotter or cooler, slowing or speeding the flow any sort of electric current fed through it. Within a digital thermostat, a current flows through the thermistor for you to some meter, which calculates the temperature derived from how quickly the resistor lets the current flow.