Why is the AC Hissing?

Air conditioners produce liquid water by design and by the simple nature of physics. Sometimes this harmlessly leaks out around the air conditioner, such as with window units, and sometimes it leaks when a drain gets blocked. There is however, a second leak an air conditioner can develop: refrigerant leaks.   The Cooling Compound Air conditioners work by exploiting physics around state-changes. When liquid turns into a gas, it can absorb heat.The effectiveness of the state change varies from compound to compound. For air conditioning, we tend to use things like R134a (freon), R12 (phased out/illegal in much of the world now), and even propane. These are all chemicals which have particular properties ideal for cooling. For example, they won’t turn solid at 0 degrees C like water, so they won’t clog up the air conditioner’s tubing and fittings. These chemicals though have some downsides we can’t really escape. Propane is outright flammable and probably capable of turning your air conditioner into a flaming set piece in the next post-apocalypse movie. R12 destroys the ozone. And R134a is toxic. It causes a wide range of symptoms from headaches to hallucinations and death in the worst case exposures.   The Hissing Leak When the air conditioner is running or has recently been run, the refrigerant will be highly pressurized. In order for us to make it work, we compress it. We’re cramming a lot of material into a small space, which […]

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Catastrophic Furnace Failure

Furnace manufacturers are fighting day and night to make home, office and industrial heating safer. In large part these efforts are incredibly successful. When you hear of a home burning down, it’s more likely that someone left their stove on than a furnace malfunctioned. This of course, begs a few questions: Do furnaces still explode? What does it take for a furnace to explode? What happens if it does explode? Failure Upon Failure Depending on the furnace design, an explosion is going to need at least half a dozen separate pieces of equipment to fail or a fair number of absurd design flaws in order for anything to happen. The pressure relief valves have to fail and become stuck shut. The furnace’s controller has to ignore or never see excessive temperature and pressure readings. The entire furnace has to run until it’s built up sufficient heat and pressure to actually explode, which it would likely never do under a regular duty cycle. A pressure explosion needs everything to go wrong. These are the sort of odds that make winning the lottery look easy. Even so, with seven billion people in the world and likely just as many heating systems having been built, failures happen. Just, what doe sit look like? Creating a Failure The only way to see a failure is to make it happen. Luckily, the Mythbusters have done this for us. It goes without saying, do not disable […]

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