That's right, with a little help you can perform the furnace installation and save. You will find that help here! The typical HVAC company will charge hundreds of dollars for the installation but, with this guide, you can save that money.THIS IS A GUIDE AND CANNOT PROVIDE ALL OF THE DETAILS FOR EVERY SITUATION. Everyone should begin with finding the proper size of unit. This can only be done with a load calculation. There are many so called DIY load calculations but this is the one area where you can lose a lot of money if you are wrong. These calculations are relatively inexpensive but they are vital. We will look at the basic procedure for gas furnace replacement. These principles can be easily adapted for the other types of units.The first step in furnace installation is to prepare the unit for installation. This includes removing all the loose parts and instructions from the unit.Then you need to decide which side of the unit the return air duct will connect to or whether it will be attached to the bottom of the unit.

The cabinets on most units are marked with the appropriate size opening, it is a simple matter of cutting the required opening in the appropriate side or in the bottom. Next, you can put the unit in the desired place. The unit should be on rubber isolation pads to minimize noise during operation.If the unit is to be located in a basement, it should be supported by blocks at least four inches above the floor.If the unit is to be located in the attic, some special precautions should be taken. best hvac home unitsA secondary drain pan should be placed under the unit. sizing a portable ac unitThis is a plastic pan that is placed under the unit to prevent damage to the home in case of blockage of the air conditioner condensate drain. ac unit for horizontal sliding window

Special attention should be given as to the location in the attic for maintenance and to minimize noise to bedrooms. **NOTE** A condensing furnace should not be installed in an attic in climates that are subject to temperatures below freezing.You need to decide which side of the unit the condensate drain will exit. When you set the unit in place, it should be close to level but sloped slightly towards the condensate drain exit.Once you have the unit in place, you can continue your furnace installation by connecting the duct system. The connections to the unit should be sealed with a metal foil tape or a duct sealant.**HOT TIP** DO NOT USE DUCT TAPE. IT WILL NOT LAST!Now, you can connect the vent pipes. On a high efficiency furnace, there should be an inlet and exhaust made of pvc. The key thing to these is to properly clean and glue the pvc joints. The pipes should be sloped back to the furnace at 1/4 inch per 4 feet. This is to allow proper condensate drainage.The next step in furnace installation is to connect the gas supply to the unit.

There should be a shutoff valve installed outside the unit. A drip leg should be installed prior to the line entering the unit. This is usually accomplished by using a tee with a capped nipple sticking out the bottom. The gas supply comes in the top and the center of the tee goes to the furnace. After installing the gas piping, ensure there are no gas leaks. This can be accomplished by spraying a gas leak detector solution on the connections. Watch for bubbles to form which is an indication of a leak.Now it is time to make the electrical connections. Your new furnace has low voltage (24v) and line voltage (120v) connections.The line voltage connections should run from the furnace junction box to a disconnect switch within three feet of the unit. It is important that you pay attention to the polarity. Most of the new units are polarity sensitive.The low voltage wires run from the furnace control board to the air conditioner and/or the thermostat. The standard connections are as follows:R terminal on furnace board connected to R terminal on thermostat usually with a red wire.

W terminal on furnace board connected to W terminal on thermostat usually with a white wire.G terminal on furnace board connected to G terminal on thermostat usually with a green wire.C terminal on furnace board connected to C terminal on thermostat usually with a blue wire. There is usually a white wire also connected to the C terminal on the furnace that goes to the ac unit.Y terminal on furnace board connected to the Y terminal on the thermostat usually with a yellow wire. There is usually a red wire also connected to the Y terminal on the furnace that goes to the ac unit.You should verify all wiring with the manufacturer's instructions prior to turning on the power.Now, you should connect the condensate drain and run a pipe to a drain location (usually a floor drain). This should be a 3/4 inch pvc pipe. The final step in your furnace installation is to start the unit and run it through a heating cycle. You should check the outlet air temperature and the temperature rise from the return to supply and compare to manufacturers recommendations.

Check for proper condensate drainage. Also perform another check for gas leaks. /wire-chart-voltage-loss-ohms-per-ft-uncoated/ on this server. Your technical support key is: 36d4-8935-1756-6707This page is to provide a single place to look to for what the safe rated capacities of various size wires in general use. general guidelines - check with the wire manufacturer or standards body controlling your installation for any additionalKeep in mind that temperature and environment have a dramatic effect on these ratings, and that for wiring it's much better to err on the side of too large a wire than too small. This page started as a page for 12V DC automotive use, but has grown over time to include a more general set of information on wire sizing. add some basic explanations of what matters when sizing a wire and to avoid using too many details specific to certain applications. used to figure this out can be very complex - for example the National

Electrical Code specifies the wire sizes to be used in excruciating detail based on years of actual research on what happens to wires in The Real World. up with all those details can be very hard, but the basic principles are prettyMy goal for this page is to expose you to those basic concepts, and at the end to give a basic "rule of thumb" chart for folks to start out This page was created to help explain concepts and give an overview of wire capacity and what is factored into deciding on the wire size to use in a givenThis page should not to be considered an authoritative source of exact numbers on what wire size to use. Consult other sources such as wiring codes and manufacturers recommendations on the piece of equipment you are installing for more details. I am not telling you what wire size to use - the information here is provided as-is and without any guarantee as to it's accuracyAny issues caused by the use of this information are not my

fault - be smart, use common sense, and use this information at your own risk. The amount of power a wire can safely carry is related to how hot it canAll wires have resistance, and as power flows through a wire that resistance causes heat - and it can be quite a bit of heat. The more power you put through a wire, the hotter it gets. Insulation breaks down as it gets hot, and at some point it will melt away leaving the wire exposed to whatever is around it - other wires, grounded metal, people, etc. The heat can even be enough to start a fire in the surrounding material in some cases. fires are nasty and tend to start in the hardest to reach places - where the most heat builds up back in dark corners and tight spaces. This is why using the right size wires is important for your safety and for safety of others using In some respects, the capacity of a wire is actually best measured in watts, notBecause a watt is a unit or power that is a combination of

amperage (volume), voltage (pressure), and resistance to the power flowingWatts measure the amount of power (aka, heat) a wire canHowever, most wire charts are done inThis is unfortunate because it means the wire chart is sort of assumed to be at aFor most usage, this is fine because the chart has anAs an example, charts for amperage ratings of of various sizes wires for 110V AC house current charts are popular and reasonably well-known. ratings are very different for common/typical 12V DC automotive usage. For example, a 12 gauge wire is commonly rated at 20A for 110V AC home usage, but in automotive 12V DC use 12 gauge wire is commonly used for circuits carrying 60A! A prime example would be the main charging wire from the alternator to the battery and out to the main electrical circuits of the car. I thought I had a satisfactory explanation posted here previously, but a few folks took aim at it and blew gaping holes in my understanding

actually explaining what I was trying to understand or explain here. I have not gotten a satisfactory explanation for this discrepancy. talked to as of yet has been able to explain it to me, but if you think you knowMaybe I'm missing something obvious. Maybe I'm just not understanding this as well I as think I am. At any rate, the chart below reflects the difference in 110V AC vs. 12V DC usage, even though I'm still at a loss to explain the details. Remember, if in doubt, it's always better to put in too big of a wire than too small of a wire. This one is a bit of a mind-boggler, but it's important. flows through a wire, it mostly flows on the surface of the wire, not throughThis effect is more pronounced on high frequency AC than it is on DC or low frequency AC. This means that a "wire" of a given size that made up of many smaller strands can carry more power than a solid wire - simply because the stranded wire has more surface area.

This is one reason why battery cables in your car and welding cables are made up of many very fine strands of smaller wire - it allows them to safely carry more power with less of that power being dissipated asHowever, this "skin" effect is not as pronounced in a typical 12V DC automotive application, and the wire and cable used there is stranded for When looking at a chart or description of wire capacity, take note of whether it is referring to stranded or solid wire - some charts may not specify but instead assume a default based on the typical wiring used in a givenFor example, almost all automotive wiring is stranded while almost all home wiring is solid. For most applications, flexibility or the lack thereof will be more important, but for very high frequency AC applications, stranded wire might be a requirement. Heat is the primary determiner of the maximum amount of power any wire can carry, and the ability of that wire to dissipate that heat has a large impact on

Wires that are run in bundles (such as in a wiring harness or wiring conduit) cannot dissipate heat as easily as a single wire run in "open air", and as such must be "de-rated" to less than their maximum value to accountAlso, wires that are run in areas that are unusually hot (such as in an attic or in an engine compartment) may need similar de-ratings. situations are encountered together (bundled wires in an unusually hot environment) then you need to de-rate for both factors and the capacity is In a car, almost all wiring is run in a bundle, and much of it runs near theIn a house, a lot of wiring typically runs through the attic, often in a bundle/group and sometimes in a conduit. Pay attention to this and size your Since all wires have resistance, the longer the wire, the greater theThis means that for longer wiring runs you need to use a larger wireThis phenomenon is often referred to as "voltage drop", and for lower voltage automotive systems, the loss of 2V or even 1V can be significant.

On longer wire runs, plan on using a larger size wire. voltage drop calculations that depend on the wire size in use, the length of the wire, the load applied, and the voltage in use. The National Electric Code has tons of charts for this, but there's a nifty online voltage drop calculator that one of my readers pointed out to me that does 120V AC as well as 12V DC - and even 6V DC. You'd be surprised at some of the voltage drops you can find just form the wiring in use, so experiment with the calculator a bit to see if it's worth going to the next highest size wire in yourOn automotive applications of only 12V, losing a single volt of power in the wire is a whopping 8% loss, so it can be a big deal for voltage critical applications like your headlights where more voltage = more light. Kudos to Ron White for providing me with the link to that calculator, and kudos to putting that calculator and other data online. Some electrical loads are continuous for long periods of times (like a light

in your house or the headlights on your car) and some are much more intermittent (like a garbage disposal in your house or the starter in your car). the wire size used - the longer a wire is in use, the more heat it will tend toA wire for something that is only used for short periods (like the starter in your car) does not need quite as large of a wire as something that will be in use for very long periods of time. This means that for long-duration uses, you must de-rate the wire even further and use a larger size. There are four basic units of measurement for electricity: There are a number of formulas that relate each of these four things - they all change in relationship to one another such that if you know any two you can calculate the other two. Lots of folks on the Internet have easy-to use calculators that allow you to do this online - below was on their website and presents the info in a pretty easy to understand This chart is a simple "max capacity" chart for a short wire run.