Improve Your Air

You’ve done your testing and your facility has an air quality problem. Stepping through your doors feel like getting a tour of an 1890s steam powered factory. It’s just gross and you’re going to turn your air into something people actually want to breathe. Physical Defenses Your first line of defense is to attack everything getting inside with some physical mitigations. Every person entering the building is going to carry allergens, pathogens, and other problems with them. Imagine someone who just walked through a grassy field, tracking pollen with every step they take. Imagine the gentle breeze blowing through the door as your guests enter, and carrying with it the latest plague to sweep the nation. There are two defenses you can use here. First, you need a nice, big, hefty door mat of some kind, that everyone ends up walking across. They’re tracking pollen on their shoes, make sure it gets stuck where it won’t cause a problem: in a fibrous tangle where it’ll never bother you again. Second, you need to regularly clean the floors of your facility. All the nasty stuff in the air is hovering around, suspended like tea leaves in water. If the air is still long enough, it’ll all settle on your shelves, floors, and equipment until someone kicks it up into the air again. Use microfiber mops to capture and remove the problem while you can. Don’t use a typical broom though, that’s […]

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Why The Thermostat’s Wrong

Thermostats are a great technology in principal. They automate a simple issue: if cold, turn on the heater. Before thermostats, someone would have to either stoke a fire or open a valve for hot water to flow. By comparison, any automation should seam brilliant, but there is a slight flaw.   Single Point of Reference In most homes and even small businesses, there’s a single thermostat, and it measures the temperature in a single place. Even in a smaller home, this can lead to drastically different temperatures across the building. Typically a thermostat’s in the center of the building to get the best ‘average’ temperature. This average however, is almost never correct. In the case of my own home, we can actually measure the temperature difference between rooms. My room is the second on the heating loop, and consequently has some of the hottest water delivered to it, the most available energy. By the time this water has reached the kitchen and living room at the end of the loop, the water’s significantly cooled, resulting in a potentially 10 degree temperature difference. These differences can be exacerbated by design flaws. The bedrooms in this house, for example, have base boards that are about half the circumference of the rooms. This allows for a ton of heat to be left in these rooms. The living areas of this house however, have a much, much lower ratio. Those baseboards are only able […]

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Carbon Monoxide Detectors

Last week we covered how a draft inducer and it’s attached pressure sensor can help prevent Carbon Monoxide from leaking out of a furnace. This week we’re moving up to the next line of defense: a dedicated Carbon Monoxide Detector. These are often installed in new homes and offices as required by local building codes in most of the United States. Where they’re not installed by construction, they’re usually installed by the facility’s owner as a precaution.   What’s the Big Deal? Carbon Monoxide is one of the deadliest, common compounds in the world. It’s is a colorless, odorless gas that will kill you at the right concentrations. There’s only two ways for someone to know they’ve been exposed to a harmful dose: Use a detector or Recognise the Symptoms before it’s too late. The initial symptoms include headache, dizziness, weakness, vomitting, chest pain, and confusion. In large part, these common symptoms can be attributed to hundreds of other ailments, including the common flu. Greater exposure can lead to passing out, arrhythmia, seizures, and death. Even then, there will be longterm complications, including memory problems, movement disabilities, and fatigue. Most people are not able to detect and react to these symptoms as Carbon Monoxide poisoning before it’s too late. They’re often waived off as a flue or some other lesser problem until it’s too late.   How Do We Detect An Invisible, Colorless, Odorless Gas? While Carbon Monoxide itself is […]

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Preventing CO2 Poisoning with Pressure

We have rollout switches and temperature sensors to prevent fires from spreading beyond the furnace. What about exhaust gasses? Almost every heating fuel we use produces deadly gasses. CO2, NO2, and more. If these gasses escape your furnace, you’re either going to leave the building or be killed by the gasses. It’s essential that we keep these gasses away from you. Your furnace has some very interesting ways of doing this and detecting a deadly hardware failure.   The Draft Inducer Older furnaces rely on physics and chemistry to get the CO2 out. As your furnace runs, it creates hot gasses. The hotter a gas is, the higher it rises in the atmosphere. As long as the exhaust is hot, it should rise up into your chimney or exhaust flue and be vented safely outside away from people. This isn’t entirely ideal, the exhaust is limited by the temperature difference, slowing it down. It’s possible for wind and other atmospheric conditions to disrupt the exhaust flow. There’s no mechanism to detect and respond to a blocked exhaust path. Modern furnaces don’t let the hot gasses just meander out the chimney. We use Draft Inducers, essentially blowers built just for furnace exhaust. These little blowers kick on a minute before ignition to vent the combustion chamber and usually remains on until after the furnace has shutdown. On the surface, this just makes the furnace burn cleaner. If there’s less carbon dioxide […]

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What is a Flame Sensor?

If a roll out switch is a master “things have gone horribly wrong, stop the show” switch and thermisters are basically limited to measuring temperature, how do we know the burner is actually making a flame? Sure, the thermister will read heat, but that takes time. Imagine the igniter has failed, it takes maybe 10-40 seconds to register enough heat to confirm a flame. The combustion chamber is now pumped full of a potentially explosive fuel mixture and nothing is happening. We need something much, much faster, we need a flame sensor.   How Not to Detect a Flame The way a person knows something is on fire is usually the bright flames and the fact that sticking their hand near it becomes really painful. This approach doesn’t quite work for a furnace. We could measure the light output, that requires more processing power to interpret the data, some incredibly sensitive hardware to detect the tiniest start of a flame, and it doesn’t work on every fuel type. There are systems that work this way, but it’s a little more expensive. We could measure the temperature, but we run into challenges with making a sensor you can shove in the heart of a flame for years on end without failure. It has been done, but it’s expensive. There are however, laws of physics we can exploit to detect a flame without anywhere near so many challenges. We can detect a […]

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Measuring the Heat

Have you ever wondered how your heating system knows to turn on? Or to turn off? You could say “the furnace controller tells it to” and “the thermostat tells it to,” but that’s not the whole picture, is it? We need a way to measure the temperature inside the furnace and inside our homes. It has to be durable, reliable, and affordable. It doesn’t have to be precise, but it must be right every time it’s measured.   A Complex Web of Technology There are a staggering number of ways to control a furnace through temperature input. A brief and nowhere near all-inclusive list of techniques include: Gas Expansion Tubes, Bi-Metal Switches, Bi-Metal Coils, Thermocouples Driven by a Pilot-Light, Thermistors, and of course modern IR Temperature Sensors found in your enthusiast-chef’s kitchen. These devices are all in some way sensitive to the heat. Bi-Metal systems expand as temperatures change. Measuring the expansion reads the approximate temperature. Gas Expansion Tubes have an internal change in pressure as temperature changes. The pressure can be used to calculate temperature. Thermocouples generate an electrical current when they’re heated. Measuring the current allows you to determine the temperature. Inside a furnace, they’re often heated directly by the pilot light or burner to read flame temperatures. Infrared Thermometers measure “Blackbody (Wikipedia Link)” radiation, but aren’t all that effective around metals or the air. And lastly, we have the humble Thermistor, which varies it’s resistance based on […]

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