Motor Overheating
An important rating on motors is the AMBIENT  temperature rating at which the motor can operate. This rating refers to the temperature of the air around the motor, not the temperature of the motor itself or even the temperature of the outdoor air, since the motor is often in a condenser air stream that is at […]
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Attic Equipment Codes
I didn't install this unit. First off, attic installations are among my least favorite applications from the standpoints of serviceability, system longevity, and a laundry list of other items. Here in Florida, it's just a bad idea due to the high humidity and temperature in a vented attic and the condensation issues that can and […]
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Thermal Balance Point vs. Economic Balance Point
The thermal balance point is the point at which a heat pump can move heat into the home at the same rate the home loses its heat. Above this point, the heat pump will not need any additional help to heat the home. But below it, the heat pump will need auxiliary heat with it […]
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A Field Guide to Conductors for HVAC Techs
HVAC work is never just “HVAC” work. One minute you're brazing copper, and the next you're troubleshooting a blown fuse in a disconnect or running a new whip to a condenser. Because our trade is so varied, you never know what you're going to find when you open a service panel or crawl into an […]
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Ohms/Continuity Basics
Some quick basics: An ohmmeter is used to measure the resistance to electrical flow between two points. The ohmmeter is most commonly used to check continuity. Continuity is not a “measurement” as much as it is a yes/no statement. To say there is continuity is to say that there is a good electrical path between […]
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That Rusty Coil/Galvanic Corrosion
How many times have you looked at the bottom right-hand side of an evaporator coil and seen all sorts of rust, even on a fairly new coil? You may have noticed that many evaporator coils and even some condenser coils will start to corrode where the galvanized steel endplates touch the copper U-bends of the […]
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Don’t Squeeze a Radiant Barrier
You are probably all familiar with radiant barriers. Sometimes, it's thin foil draped under the roof deck. Other times, it's used on the inside of stud walls or over furring strips before the drywall goes up, and there is even plywood with a radiant barrier attached to one side that is used for roof decking. […]
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Do You Replace the Contactor and Capacitor With a New Compressor?
Replacing a compressor is expensive, time-consuming, and physically taxing. If we are replacing a compressor, I want us to be doggone sure we aren't going to be dealing with the same thing again, and this often includes a shiny new contactor and capacitor (on single-phase units). There are a few schools of thought on this […]
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3 Bad Techs Who Don’t Know It
First, let's state the obvious and clear the air a bit. The photo above is SUPER CHEESY! But this story is about three bad techs who don't know it, so a photo of three models clearly posing in clean clothes makes as good a proxy for a bad tech as anything else. First off, I'm not […]
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