HVAC Basics

 So HVAC that stands for heating, ventilation, and air conditioning. All air conditioners. Absorb heat. They don't actually make cold air, which is something that most people find surprising in the beginning. But when an air air conditioning system works correctly, it removes heat from the home such as this, and then it, it expels the heat outside through a condensing unit.

So the thermostat is the, is the brains of the operation. It communicates to everything in the system, whether it's time to operate and what the settings are. So we have a thermostat. Indoors. This is the part that's called an air handler. This is the section of the HVAC system where heat is absorbed. So air will go through here, through the filter, through the AC coil, the evaporator coil, and through conduction, it will absorb heat into the refrigerant, get pumped outside where a fan blows on another coil, and expels the heat outside.

So if you could imagine holding a glass of water and it's hot, you can feel the temperature through the glass. Well, that is conduction, so, so if you put warm air in here, it goes across the filter around the metal. The metal conducts the heat into the refrigerant, then it gets pumped outside and heat gets expelled into the atmosphere.

So let's take a look at the thermostat. Let me say this. Every technician that's really good at HVAC always has a routine and they start at the thermostat. It's very tempting to think, oh, I know what it is, and you very well may. But if you have a point of origin for all of your troubleshooting, your accuracy in troubleshooting will will be much greater, more accurate, more precise over time.

So let's take a look at the thermostat. We have settings here we have for the fan only, which is on and auto. So what I'm gonna do, if you look at the thermostat, it's off right now. So what I wanna do is turn the fan to auto. I'm gonna turn this to cool and now it's set at 69, so I'm gonna push this down and the fan should come on perfect.

Very often there's a delay, so you may have to wait 30 seconds a minute, sometimes 2, 3, 4, 5, but now you can hear the air going through here, so I want to have this temperature. Most technicians will bring it down five or 10 degrees to make certain that the system is calling for cooling. Now you can hear the fan.

So what does that tell me? It tells me that that part of the thermostat, those parts of the wiring in the system are good. The air handler is good, the capacitor is good. It has 240 volts and that everything inside so far is working except for the heat. We'll check that in a minute.