James Harrison's first mechanical ice-making machine began operation in 1851 on the banks of the Barwon River at Rocky Point in Geelong, Australia. His first commercial ice-making machine followed in 1853, and his patent for an ether vapor compression refrigeration system was granted in 1855. This novel system used a compressor to force the refrigeration gas to pass through a condenser, where it cooled down and liquefied. The liquefied gas then circulated through the refrigeration coils and vaporized again, cooling down the surrounding system. The machine produced 3,000 kilograms (6,600 lb) of ice per day.[citation needed]
In 1992, a non-governmental organization, Greenpeace, was spurred by corporate executive policies and requested that a European lab find substitute refrigerants. This led to two alternatives, one a blend of propane (R290) and isobutane (R600a), and one of pure isobutane.[18][22] Industry resisted change in Europe until 1993, and in the U.S. until 2011, despite some supportive steps in 2004 and 2008 (see Refrigerant Development above).[27][67]

If you hear clicking that is followed by a hum or buzz, you’re probably hearing the fan motor attempting to start without the boost it needs from the capacitor. You can almost always conclude that the capacitor has failed. Sometimes you can get the compressor fan spinning (clockwise) by pushing it with a thin stick or long screwdriver poked through the grille. But the chances are good that this might work for one cycle, but the capacitor will fail next time the AC goes on. It’s best to replace the capacitor.

Furnaces and thermostats are not mix-and-match appliances. Using the wrong type of thermostat with a furnace will cause operating problems and can be dangerous. Although thermostats look similar, they are designed very differently. There are numerous types of heating systems and thermostat systems and they need to be coordinated for safe and proper operation. There are three types of thermostat systems used today: millivoltage, low voltage, and line voltage.​