Introduction to Heating (HVAC)

Hello. My name is Dave . I am the Heating and Refrigeration instructor here . This is normally called the HVAC program but what it is is Residential Heating and Air-conditioning and commercial refrigeration. The term HVAC stands for: heating, ventilation, air-conditioning, and then we put a slash R (/R) on there and that stands for refrigeration. All that falls under the category of what we’re going to do in this program. We’re going to talk a little bit about residential heating and air conditioning, and commercial, and then we will go on from there. One of the the first things you need to kind of understand about heating refrigeration is a theory where heat transfers from hot to colds .That is the principle by which how we,  at,  heat/cool a house or a place of business. And we use those principles and we use our equipment to make that happen so we can maintain a temperature inside the building that is comfortable for us. The ventilation part is air quality. And in the field, we call that IAQ; indoor air quality. And when we get into that, we’re talking filters and humidity and things that make the living more comfortable.

Air-conditioning is actually a term meaning conditioning of the air for comfort living. There’s not very many places you can go to that doesn’t have heating refrigeration in the building. I like to tell my students that you can’t go to the moon without heating and refrigeration. So it is a very vital part. So we’ll get into all that out in the shop. Okay. We’re out here in the shop now and we’re going to take a look at the furnace.

One of these three types of furnaces, you will have in your house. And the first one we’re going to look at is this one here. It is a Train but the brand name really doesn’t matter. This furnace is what we call a natural draft furnace. It was probably – and this is probably in the range of about 25 to 30 years old It was an efficiency furnace in its day. And it draws air from the house and through this opening and creates a draft up the flue and out. And that’s where it gets its name; natural draft. In its day, it would be rated about fifty to sixty percent efficiency; meaning, that about 50 to 60 percent of the gas consumed was converted to heat for the house. And that is the natural draft furnace. From this point, we migrated to what they call the induced draft furnace.

Now this induced draft furnace, in the efficiency rating, is about eighty percent. Meaning that eighty percent of the gas consumed is converted to heat. And you’re losing twenty percent up the flue. Basically the furnaces work the same, they just have added more efficient components and safety devices to get to the point where the furnace achieves said efficiency. After the eighty percent efficiency furnace, we move into the ninety percent efficiency furnace. This again means that ninety percent of the fuel consumed is converted to heat for the home, and you’re only losing about 10 percent or less up to the flue pipe. The interesting thing to note here is that our flue pipe now, is schedule 40 plastic pipe; where with the other two types, it was metal. And that’s because the manufacturers designed a second heat exchanger to absorb that heat, which makes a furnace more efficient, and allows us to vent this furnace out through the side of the house rather than going up through the chimney with the other two.

So that is one of the three types of furnaces you will find in your home, unless you have an electric furnace and we have an electric furnace sitting here on the table. It works on total electricity. And it is – according to the manufacturers, it is rated the most efficient because you get one BTU of heat for one kilowatt of electricity. But when the homeowner takes a look at it, that kilowatt adds up and really drives your electricity bill pretty high. So even though it’s high on the efficiency it’s probably not a furnace most people would choose unless they we’re using propane. It would be cheaper than using propane for a fuel. But those are the different types of furnaces you would find in your home and that’s what we’re going to talk about in this course. Those three units that we looked at a few minutes ago are residential units. Now we’re taking a look at a commercial unit. Another name for this would be called a package unit.

You find these on the rooftops of buildings, and sometimes even alongside the buildings. It’s called the package unit because on this side of the unit over here, is the air conditioning side. And on this side over here, from this area to here, is the furnace area. So we have the furnace and the air conditioner all put together in one package unit. This is about a six ton unit, which is pretty small for commercial. Commercial equipment gets a lot of that’s up around 20-30 ton or larger. But this one here we have it setup so that we can train the students on.

And again this would be in the category of about an eighty percent efficiency furnace. Once again, meaning that eighty percent of the gas consumed is converted to heat, and we have 20 percent going up the flue. It’s very much like the residential equipment. So when students are trained on residential, they can also work on commercial. A lot of techs like the commercial equipment because everything is combined in one area, and it’s pretty easy to work on. In your residential unit, usually your furnace is in the basement and your air-conditioner sits outside. So you have a little more running back and forth, but it’s the same thing. Once you know how to work on a residential unit you’re very qualified to work on commercial. On the back side of this unit is where the air comes out and it is docked into the building by means of ductwork that carries the air throughout the building. And we will take a look at this later on. We’ll go through it, and we will fire the furnace. And then we will fire the air-conditioner, and you will get a chance to see how that’s worked.

We will do some troubleshooting; things that the technicians today are doing. Everybody is starting to turn their furnace on now for the winter. So all the companies are doing what they call winter tune-ups. and that’s where technicians would come out to your home, and they would go through the furnace. Check the operation. Make sure all the safety components are working properly; the motors are oiled. And in the next video too, we’ll go through some of those steps to show you what’s going on. But once again, this is your commercial unit..

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