Destructive Dirt and Debris

Your air conditioner has an enemy, a nemesis to rival dirty air filters. Dirt, Debris, and overgrown plants are the outdoor equivalent of dirty filters. It is essential that your condenser gets as much undisturbed airflow as possible. That means no dirt on the coils, no bushes blocking off its sides, and no leaves piling up around it.   Why Is This a Big Deal? Your air conditioner essentially collects heat from inside your building and then radiates it into the air outside the building. This has a few prerequisites: lots of air, lots of thermal-contact with the air, and ideally lots of airflow to replace the heated air with fresher, cooler air. The condenser was designed to provide all of these things. There is a fan to suck in more air. There are thousands of tiny metal plates weaved back and forth inside the coils. These coils are made extremely conductive metals that will help radiate heat into the atmosphere. Things go downhill fast when you start interfering with these features. Dirt is especially a vicious enemy here. The metal of the condenser coil is an amazing thermal conductor, readily blasting heat into the atmosphere. Dirt however, is not a good thermal conductor. Most dirt is going to act more like an insulator and reduce the amount of heat that flows from the condenser coil into the air around it. Less heat-flow means less capacity. Your 39,000 BTU system […]

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What’s the BIG Problem with my AC?

Every season there will be a fair number of people with small problems in their air conditioners. They’ll experience leaks, failed belts, and maybe a few minor electrical issues. These are all little wear and tear things that your contractor can fix for a few hundred dollars. When an air conditioner gets older however, things start getting a little more expensive. There can be some big things starting to fail.   Dead Compressor The compressor is that big, typically black, cylinder or spherical object in your air conditioner. In many ways it is the heart of the system. The compressor will receive refrigerant and through one of many ways, squeeze it down. This compression is what lets us remove heat from the air elsewhere in the system. When the compressor fails or begins to fail, you might experience warm air blowing from the air conditioner instead of cold air, regardless of temperature setting. The system may have difficulties starting up, draw excessive power, burn through fuses, or trip its breaker. When the compressor fails, there’s really only two areas things can go wrong: the motor or the compressor assembly. If the motor starts to go, it’ll perform poorly and draw more power to start and run. Eventually the motor will just get hot and stop cranking the compressor assembly altogether. At that point, it’ll probably blow a fuse and start melting internal components. On the other hand, there’s also a […]

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Why Isn’t my AC Working!?

It’s spring, mother nature is keeping you in the eighties or nighties already. Your office is unbearable. The intern has somehow duct taped ice bags to his back and ruined his office chair in the pursuit of not melting. It’s time to turn on the AC and nothing happens. Kronk throws the lever and the air blasting in is hotter than the pavement Dave the Intern cooked his lunch on. What happened?   The Little Problems There can be a million things wrong with your AC. Some issues are catastrophic and very expensive to repair as our lead sales guy Scott learned the hard way just a few weeks ago. Other issues are smaller, cheaper, and merely annoying. Did you Turn on the Power? Most central cooling systems have a dedicated circuit breaker to turn them on and shut them off for maintenance and long-term deactivation such as through the winter. Turning off this breaker in the fall ensures your air conditioner physically cannot be engaged in the winter and accidentally damage itself. Depending on your situation, you may not have known this switch exists or your building maintenance team just hasn’t turned it on yet. If you enable your air conditioner in your thermostat, crank down the temperature, and nothing happens, this is the first thing to check. If you know where the breaker for your AC is, check on it. If you don’t, contact your building maintenance team […]

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Why Are Compressors Measured in Tons?

When we look at compressors, there are a lot of numbers going around, but one of the bigger ones is the Tons. We sell compressors in all manner of weight-ratings, from less than a ton to hundreds of tons. The thing is though, this doesn’t mean we need a crane and a massive truck to load the compressor before it ships out. Compressor tonage is not actually a measure of weight. In fact, it is the result of some weird and convoluted math and history.   Old Fashioned AC Before we had the modern air conditioner, there were just a handful of ways to actually cool a room or a building. You could open a window, sit in front of a fan, use an evaporative cooler, or get a block of ice. That’s right, once upon a time we didn’t just have “ice boxes”, we had ice-conditioning too. The precursor to modern refrigeration was massive chunks of ice, usually cut from frozen lakes in the north and hastily delivered anywhere cooling was needed. You would go down to your local ice house and buy however much your fridge or cooling system needed. For building-scale cooling, there would be a block of ice essentially placed in a special cabinet in the air ducts and fans would blow air over it. The ice would remove heat from the air and melt. The air would be cooled and circulated around the room or […]

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What About the Other Compressors?

Just how many ways are there to squeeze down a gas? If you look at the entirety of the industrial world, there’s probably a few hundred different devices. If you look at HVAC, luckily the list is a lot shorter. The air conditioning world relies primarily on five compressor designs.   Reciprocating This compressor works pretty much exactly the same as a car engine does, but without the gasoline and combustion. Inside a car you have your cylinders and pistons. When the piston moves up it compresses, when it goes down it sucks. The same principal is used in a reciprocating compressor. At the base of the compressor there will generally be an electric motor, which turns a shaft. The shaft has a bend in it to allow for offset motion. At the bend there’s a connecting rod, which links the shaft to the piston. When the shaft spins, the piston moves up and down. On the downstroke, fresh refrigerant is pulled in. On the up stroke the refrigerant is compressed and injected into the refrigerant loop. This particular design is popular in residential scale compressors. There are more parts involved, so there’s a greater chance of hardware failure, but the well understood nature of the piston and cylinder as well as massive manufacturing tolerances make them cheap to manufacture. Consider, steam engines were around in the 1800s, and this is the same principle as their driving pistons. The complexity […]

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How Does a Scroll Compressor Work?

Once upon a time, I thought there was really just one kind of compressor. How many ways can their possibly be to make something smaller? Turns out, quite a few. Each type of compressor has its own quirks. Some designs are more efficient. Some require less maintenance. There’s just this endless list of trade offs in designs to get a […]

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When CAN we turn on the AC?

As the weather warms up, we’re caught in a bit of a pickle. Some days it’s 60 or 70 degrees outside, but other nights we can still see lows dipping to 26. Some days we look to our AC systems and desperately want to run them, but is it time? Is it good to run AC for just a few hours a day? Is it good to run them in the bitter colds nights? Are we going to regret running these?   Physics Hate Us We’re going to run into a few issues running our air conditioning in less than roasting weather. We’ve built modern AC, from window units up to multi-ton rooftop monsters, to take a brutal 100 degree summer down to a cool 70 degree oasis. These machines can create temperature drops from twenty to forty or more degrees. This involves creating some intense coolness inside the air conditioner. If the ambient air is 60 degrees and we drop that by 40 degrees inside the air conditioner, we’re going to make it 20 degrees inside. This extreme cold will create ice, the great nemesis of all things mechanical. We don’t start to get to ideal temperatures until it’s about 70 degrees outside. Around that point, we can actually run the AC without having to worry so much about the ice build up. Why is ice a problem? It’s mother nature’s wedge. As water freezes it expands. As water […]

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Why Can’t We Crank the Heat AND the AC?

We’re entering the awful, awful season where mother nature will swing between very warm and very cold. Just last week we had a good four inches of snow, a high of forty degrees, and a low below freezing, only for a high of over fifty the very next day. This weather calls for both heating and cooling in some circumstances, but we can’t always give you both.   Fond, Freezing Memories The schools I went to growing up had a very annoying problem: they could heat or they could cool, but they could not do both. This was always problematic and stupid to kid-me sitting at his desk contemplating a textbook bonfire for warmth. Of course, it’s wasteful to run the heating and cooling at the same time, but surely we can just turn off the furnace and crank up the AC? We’ve done it in the car all the time, you just twist a knob and you go from freezing to roasting and vice versa. At small scales, climate control is pretty easy to accomodate. You use air ducts and mix hot and cold air to get the net desired temperature. Facilities with forced air heating and cooling can pretty readily fling themselves from one temperature to another like your car. Other facilities have completely separate systems for heating and cooling. There might be a little split AC unit in every room and a master hot water heating system. […]

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Are Condenser Covers Necessary?

One of the most overlooked parts of having a central air system is covering up your condenser. Most people think, “it was fine all summer, so winter will be no different.” We would beg to differ on this, for the simple reason that winter is Cold and Cruel to machinery. Just think for a moment of how many things you leave outside and find ruined by nature.   Dirt and Debris The smallest thing to worry about is what can get inside your condenser that shouldn’t be there. As temperatures drop, trees are going to lose their leaves and smaller branches. Rodents will invariably seek shelter anywhere warm or enclosed. And of course, wherever small rodents go, they’re going to build a nest. Where rodents build a nest, they’re probably also going to find some tasty wires to nibble on through those long, cold nights. These things may seem minor, but they can be a real pain come spring. You’ll need to get the cover taken off and remove all the debris that shouldn’t be there. You’ll need to wash off your condenser coils in order to get the maximum possible efficiency. If any little critters got in there and had a tasty copper and rubber salad, you’ll also have to invest in the repair guy coming out and replacing something expensive. Who wants to put up with that?   Water Damage There’s also the threat of what water can […]

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Multizone HVAC: The Ductless System

Multizone systems can be big, complicated, and a challenge to cram into small spaces. If you’re using hot and cold water for your heating and cooling, you need to install valves and actuators everywhere, possibly install a whole second set of pipes for a “dual pipe” system that meets any need, and make sure you can pump enough water to satisfy the beast. In forced air applications, you would have to tear apart your ducts to add the controls and fans, then spend ages locating and sealing every leaking part. This nets you a working system, but it could be better and easier.   The Central Problem We tend to centralize our HVAC hardware as much as possible. You do all your heating and cooling in one place, then send the air or water around the building. It makes a lot of sense. You only need one or two boilers for most places, even industrial settings. Put it all in one place and save on energy costs and complexity, except when you want granular control. With a central heat or cooling source, you need to add tons of controls to manage the flow hot and cold air. You’ll lose a lot of energy by sending air and water around too. Leaks in air ducts and pipes radiating heat into the open air pose annoying losses in efficiency. There’s only so much you can do to fight nature’s hell-bent desire to […]

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