Fall AC Maintenance

It’s getting cooler outside. The high today in Philly isn’t even 80 degrees. Just a week or two ago we couldn’t go a day without seeing 90. In another few weeks, we’ll be struggling to see the 70s and we’ll be turning to warmer clothes for the start of fall. As with all things, that means now is about the best time to prepare for winter with some pre-emptive maintenance and cleaning.   We’re Going to Maintain Something… We Won’t Be Using? It’s always best to work on things when you don’t need them and better still to work on them just a little ahead of time. The weather outside is nice and pleasant right now. You can walk outside in a T-shirt and not feel like your arms are going to freeze off. It’s a good time to do any outdoor work before mother nature gives you a nice, awful cold for your troubles. In the case of your air conditioner, there’s a fair bit you can do to get ready ahead of the season. You can clean the area around your condenser, your HVAC contractor can clean out the drainage connections for the drip pan, you can order a protective cover to keep your condenser free of debris throughout the winter, and you can do one last inspection for any worn parts. There is some logic to all of this. Debris is going to trap water from rain […]

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What Happens to Fire Alarms in a Power Outage?

Fire safety is serious business. We’ve covered how alarm panels, their sensors, and the entire sprinkler system are designed to survive the end of the world. This extends beyond the panel itself and straight on to the infrastructure that runs it. Even during a power outage, most alarm systems will continue to function perfectly.   The Battery Backup Most alarm systems have an integrated back up for when the power grid, or even building power supply fails. On the whole, an alarm system is a really low-power set up, making it ideal for battery operation. The fire panel itself is mostly a massive input/output complex, with just a handful of memory chips and processors doing the heavy lifting. In an extremely simplified sense, you could imagine the fire panel as a cell phone mother board, wired up to a massive sensor system. The battery powering your cell phone is pretty tiny, but yet it keeps your phone chugging along for 12-48 hours, depending on the model and how exactly you use it. Now just imagine a bigger, simpler lead-acid battery, and it’s also powering a couple hundred smaller sensor devices, with cell-phone like processors in them. That is the situation inside most fire panels and other similar safety systems. In most cases, local fire codes requires these alarms to function for about 24 hours on batteries alone. Given we’ve seen countries like Puerto Rico go dark for months from natural […]

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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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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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Can Cold Weather Damage my AC?

Winter is slowly coming. Here on the East Coast, we’re starting to see a gradual cool down as Summer turns to Fall. We’re probably near our last week of 80 degree weather if we’re not seeing it already. That means we need to talk about shutting down the AC. In most cases, you can’t run the air conditioning through a North Eastern winter. Cold weather can, and will destroy your central air, split system, rooftop and window units.   The Water Problem The air conditioners we have today have a dangerous relationship with water. Back in the early 1900s, air conditioners started out as enormous, expensive dehumidifiers. The fact that these machines cooled the air was just a side effect until people started to like the idea of comfortable work places. This means that air conditioners collect water. Water vapor in the atmosphere will condense on anything cold, such as the evaporator coil in the home or the tubing connecting indoor and outdoor components together. This isn’t normally much of an issue. In fact, during the summer it’s a good thing. The water collecting on the system helps it to better conduct heat and ultimately operates more efficiently. During the winter however, things become more problematic. Between the cold air and the cold AC, all that condensed water is going to freeze somewhere along the line. It becomes an issue of keeping the air conditioner warm with the air from […]

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