The Mechanical Parts DO Fail

We use clever design and parts like bearings to prolong the life of our mechanical equipment, but that’s not enough to save them indefinitely. Even if the immediate friction of metal on metal doesn’t kill something, there are other forces at work that will. It’s only a matter of time before something gives out in a big way.   Friction is STILL the Enemy Bearings let us reduce the friction between spinning parts, that way we don’t have metal grinding on metal inside motors, valves, vents, or anything else mechanical. That’s not where the friction ends though. Friction is literally everywhere. Whenever two materials touch, there will be friction, including between the air and water against an object. This is destructive. Air and water seem soft and safe to us, but they’re actually capable of being extremely destructive over time. This is most evident in pumps. The impellers spin and push the water around, creating movement and pressure. A new impeller will have precise, ‘teeth’, shrouds, that work direct the water like the blades of a fan. Over time however, the smallest imperfections will be worn into massive design failures. These shrouds will be worn down until they don’t trap, grab, and push water around anymore. They won’t hold up to pressure anymore. Overtime, the water is grabbing bits and pieces of the metal itself and just carrying it away. Any weaker parts of the pump will be eaten and […]

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What Causes Electrical Arcing?

Most everyone in the world has seen an electrical arc. Lightning, certain short circuits, and other times when there is literally electricity moving through the air are all Arc Flashes. We’re going to look into the fundamental causes of electrical arcing.   Moving Power Electricity is essentially a charge being conducted through a wire. All electrical charges want to disperse as quickly as possible. They’re like water behind a dam: it always wants to get out. In the case of electricity, the charge wants to disperse, positive to negative. It always wants to get to ground. The problem with this is that we want to actually use the electrical charge, so it can’t go straight to ground. We use insulators to keep the electricity essentially safely inside the wire. Without the insulator, the charge would get out and work it’s way to ground like water out of a burst pipe following gravity. Insulators can be a wide range of things. The rubber casing around wire is it’s insulator. The gigantic, ceramic cones on utility poles are insulators that prevent the charge from trying to discharge into the wooden pole. The air itself is also an insulator. Electricity generally does not want to move through the air. This is why we can have electrical sockets exposed to the open air, but not to water. The air won’t easily conduct an electrical charge but the water will. Water isn’t a great conductor, […]

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The Importance of Insulation

Throughout the winter, plumbers repeatedly get calls for one thing above all others: burst pipes. The problem is that as the environment gets colder, pipes start to get colder. Eventually the pipes chill to the point that they’re below-freezing. Once this happens, burst pipes are all but inevitable.   Water’s Expansion Problem As materials change temperature, they change states. As states change, their volume, the space they take up changes. When water freezes, it’s molecules change from an energetic, freeflowing state to a rigid crystal structure. This causes the water to take up more volume. It’ll expand in every direction. Unfortunately, the excess material won’t push out through a relief valve or anything non-destructive. Once it becomes solid, it just is solid. There’s no in-between, gelatinous phase where excess material can still be squeezed out. If you freeze water in any rigid container, it’s going to get destroyed. This can be demonstrated at home with a simple, disposable water bottle. If you freeze it, the bottle swells out to take on the shape forced on it by the water. If you have a drinking glass you want to destroy, freezing that would destroy it as well. The copper pipes in your building are exactly like the glass. Although copper is a very flexible and malleable material, it will be more brittle when its cold. It will be less flexible. With high heat, you could expand the copper pipe by pushing […]

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Why Won’t the Furnace Run?

It’s a bad sign if a furnace is starting and stopping too often (short cycling). It’s bad if it’s just running all the time. What could be a worse sign? Well, what’s it mean if the furnace won’t start in the first place? At least if your furnace short-cycles, you’ve got heat and you know it’s not a catastrophic failure. Things get scary when it won’t cycle at all.   The Easy Suspects Your furnace isn’t running. Don’t panic yet. If we were to round up every contractor in our books and ask about simple break downs, the stories would never end. Simple, cheap, and even silly things can bring on the chill. We think the most common ones are: Ran Out of Fuel Empty tank Clogged fuel line Gas main shut off Electrical Shut Off Someone bumped a shut off switch Breaker tripped during storm Failed switch or contactor stuck in the off position Thermostat Wire Cut Wires chewed by a mouse Wires damaged with nails or screws in the wall Chimney blocked With debris With a birds’ nest Minor Hardware Failure Bad Pilot light Bad ignitor Bad flame sensor   When we say these are common events, we really mean it. I’ve experienced at least three of these. My home furnace is a nice little oil burner, and we’ve run it dry during the winter. We’ve discovered our fuel pipe doesn’t dip to the bottom of the tank. […]

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What is Short Cycling?

Everything around you is designed with a specific set of uses. Consumer lighting is generally designed to be in a warmer environment, be turned on for a few hours, then be shut off for a few hours. Your car is designed to start up, run for at most a few hours, reach a few thousand rpm, carry a given load, and then shutdown for a while. Everything is designed with these use constraints, that they’ll be on for a given time, achieve a given performance, and then shut down. We call this off, on, off pattern a Duty Cycle.   Getting Out of Cycle Your car works wonderfully when you use it as its designed, doesn’t it? Short trips to the store, the commute to work, and the occasional long haul trip all work out just fine. What would happen if you didn’t use it as intended? Imagine if you ran it for short periods. Start up, drive to the stop sign, shut off. Start up, drive 5 minutes, shut off. Start up, drive around the corner, shut off. Something is going to break eventually. Either the starter will have overheated or the battery will die, but it’s going to work a lot shorter than desired because it’s designed Duty Cycle is being interrupted. This disruption, a constant start-stop is short cycling. The system keeps going through cycles, but they’re shorter than they should be. Just as with the car, […]

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Freezing a Freezer

It’s the very end of fall, bordering on winter, and we’re going to look at air conditioners and refrigeration. Every year, someone learns the hard way that you both can and cannot run an air conditioner in the middle of winter. Let’s get to it before someone else learns a hard, expensive lesson.   Who Runs the AC in WINTER? Someone out there will ask, so let’s head it off sooner than later. In an ideal world, you could pull in fresh, outside air, particularly when it’s cooler outside to cool your facility. This works in homes and even small businesses, but there’s challenges when you move into specialist industries and larger scale operations. Hospitals can’t just open the windows, as it can expose the patients to bacteria, viruses, and allergens. Restaraunts can’t leave their frozen food up to mother nature’s whims to keep it cold and safe. Large data centers need to be sterile and cool year-round, to the point that the air outside cannot easily keep up against the heat generated inside. Manufacturers in numerous industries need cool areas, for chemical work, storage, freezing food, and so on. In all of these cases, nature is too unpredictable, too unreliable, or just too complicated to fulfill our needs. These places need to run air conditioning and refrigeration even through the coldest and darkest of winters.   The Freezing Problem Regardless of application, all refrigeration systems have one big nemesis […]

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What is a Rollout Switch?

Your furnace is full of sensors, regulators, switches, and detectors of near everything. There are flame sensors, temperature sensors, pressure switches. That’s a lot of stuff that mostly feed into a controller that operates the furnace as long as it sees all the right readings. That one device is an almost single failure point. The only good way to stay safe is with redundancy. In most cases, these are physical, mechanical safeties which will over-ride every other part of a system and force it to stop cold. Cutting Power on Failure The Roll Out Switch is in simplest terms, a very fancy fuse. Most furnaces will have several of them spread throughout, each tuned to a particularly temperature. One near the burner or heat exchanger may be designed to trip if the furnace exceeds it’s maximum rated operating temperature. Another near the controller board may be set much lower, perhaps around 90 degrees celsius, just shy of when most silicon chips start to fail. Some may rest near the fuel line and manifold, set to extremely low temperatures, in case a leak and fire occurs away from the burner. In the event that any of these switches trip, all power to the furnace is cut. There’s no shutdown process, it just loses all electrical power. If things were going wrong or at risk of going wrong, this usually stops the problem dead in its tracks. A shut down furnace cannot […]

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