Your Friendly Local Electrician

Archive for the ‘furnace’ Category

Everyone use electricity to power our homes, business, televisions , lights, etc. With AC or “Alternating Current” , the current alternates in direction on a regular basis.  This has shown to be a better way for providing electricity than “Direct Current” Electricity or DC Electricity.  This is because the voltages can be changed if needed. Using AC electricity in homes also allows for other devices to be used

While direct current (DC) electricity flows in one direction through a wire, AC electricity alternates its direction in a back-and-forth motion. The direction alternates between 50 and 60 times per second, depending on the electrical system of the country.  This change happens in a cycle.  Each cycle is also called a Hertz (Hz).

AC electricity is created by an AC electric generator, which determines the frequency. What is special about AC electricity is that the voltage can be readily changed, thus making it more suitable for long-distance transmission than DC electricity. But also, AC can employ capacitors and inductors in electronic circuitry, allowing for a wide range of applications.

We say AC electricity instead of simply saying AC, since that is also the abbreviation for air conditioning. You need to be specific to avoid confusioning issues and to avoid any misunderstandings while discussing a topic like this.

With an AC generator, a slightly different configuration alternates the push and pull of each generator terminal. Thus the electricity in the wire moves in one direction for a short while and then reverses its direction when the generator armature is in a different position.

The charge at the ends of the wire alternates between negative (−) and positive (+). If the charge is negative (−), that pushes the negatively charged electrons away from that terminal. If the charge is positive (+), the electrons are attracted in that direction.

AC electricity alternates back-and-forth in direction 50 or 60 times per second, according to the electrical system in the country. This is called the frequency and is designated as either 50 Hertz (50Hz) or 60 Hertz (60Hz).

The regular back-and-forth motion of the electrons in a wire when powered by AC electricity is periodic motion, similar to that of a pendulum. Because of this periodic motion of the electrons, the voltage and current follow a sine waveform, alternating between positive (+) and negative (−), as measured with a voltmeter or multimeter.

There are distinct advantages of AC over DC electricity. The ability to readily transform voltages is the main reason we use AC instead of DC in our homes.  The major advantage that AC electricity has over DC electricity is that AC voltages can be readily transformed to higher or lower voltage levels, while it is difficult to do that with DC voltages.  Since high voltages are more effecient for sending electricity great distances, AC electricity has an advantage over DC. This is because the high voltages from the power station can be easily reduced to a safer voltage for use in the house. Changing voltages is done by the use of a transformer. This device uses properties of AC electromagnets to change the voltages.

AC electricity also allows for the use of a capacitor and inductor within an electrical or electronic circuit. These devices can affect the way the alternating current passes through a circuit. They are only effective with AC electricity. A combination of a capacitor, inductor and resistor is used as a tuner in radios and televisions.

Mercury filled thermostats served their purpose in the past.  However, times have changed and digital programmable thermostats are the way to go now. With electric and gas prices skyrocketing, a digital thermostat will save you money. It will turn the furnace and air conditioner on and off automatically. The best part is they can be set for different temperatures at different times of the day.

Before you begin, read the manufacturer’s instructions that were sent with the thermostat. These pages will guide you by step-by-step instructions on how to install the device before you begin.  You will also have to assemble the tools that you are going to use.  These include screwdrivers, wire Strippers scratch Awl (for making a hole in the drywall for the new plastic anchors), hammer and a level.

Before doing any electrical work, shut off the power. In this case, the circuit feeding the furnace controls the power to the thermostat. Go to the breaker or fuse panel and turn the breaker off or fuse out.

You have to remove the old thermostat first.  Begin by taking the face plate off of the old thermostat and remove the mounting screws. This will expose the thermostat base. Carefully remove the wires from the thermostat base. Mark down on a piece of paper which color wire goes to what terminal. It should be red to “R” for power, white to “C” for common, blue to “Y” for cool, and green to “G” for fan. Be sure to tie the wires together so that they don’t fall into the wall.

Remove the old base by removing the mounting screws. These may be screwed into plastic anchors. These mounts probably won’t work with the new thermostat.

In order to install the new base, you’ll need to install the new mounting hardware. Usually the manufacturer will send some plastic anchors. With a drill bit slightly smaller than the anchor, drill the holes for the new base. It’s a good idea to level the thermostat for looks.

Using the paper that you wrote the wire colors on, connect the wires accordingly to the new thermostat. Remember, each color goes on only one terminal screw.

Now attach the new thermostat to the base and install the cover. Depending on the model, this may be mounted with screws.

The final step is to turn the power back on and test the thermostat. Check to see if the thermostat is functioning properly.  Be sure to tie the thermostat wire back so it doesn’t fall down inside of the wall.  Take note of the wire colors and the marked terminals they are connected to. This is important for reconnecting.