HVAC school reviews the components of the basic heat pump and how they all work. Featuring Jesse Claerbout and Bryan Orr.
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Read all the tech tips, take the quizzes
and find our handy calculators at https://www.hvacrschool.com/
Hey Brian, with hvac school here today, I asked Jessie to make a video about a heat pump system and go over a couple different things, but this particular video. I wanted him to just cover the basics of a heat pump system, the different components and how it all works. The biggest thing to know is is that in a heat pump, you're taking heat from the outside and you're pumping it inside, I think that's probably where they got the name from it's kind of a weird name. The customers are always looking for or they see pump.
One component that pumps heat, but really it's an air conditioner in an air conditioning mode, we're taking heat from the inside and we're moving it outside and a heat pump were taking heat from the outside of moving it inside. But he's going to review a few. A little bit more about how that actually works. Most of us understand the cooling cycle.
How this operates? We're going to have our liquid line coming through here, hitting our pool mode TXV flash gas go through the expansion tubes go through the evaporator coil and, at the end, we're coming out of our suction line as a superheated vapor going back to the condensing unit goes Through the compressor comes out as a hot gas goes through, the condensing coil turns back into a liquid and the whole cycle repeats. What a lot of us don't understand is the heat pump and how that works. So on a heat pump system, you're gon na have your standard components, your evaporator, coil and cool mode. This is gon na, be your evaporator coil and heat mode.
This is going to be your condenser coil. Then you have your blower wheel, housing, your blower motor blower wheel, that's standard stuff here, you're going to have your blower board and then you're going to have your heat strips. The key strips on a carrier system are located here. The design of the heat strips are to be used if the system cannot maintain the temperature in the space.
So if the temperature is so cold outside it's below the balance point for the heat pump portion of the air conditioner, then the heat strips will kick on. In addition to the heat pump to create additional heating for the space. Also, a function of the heat are when the system that goes into defrost that allows the system to turn on the heat strips during the defrost cycle, to prevent it, cooling off in the space, all right, real quickly to kind of go along with what Jesse's saying I want to show you the basic components of a heat pump and in this case we have our. You know we have our outdoor coil and you can see it's coming from the compressor and it's going into the reversing valve and then out of the reverse and goes to the outer coil.
And then it turns into the liquid line. It bypasses the heating expansion valve or heating metering device on the carrier that we have here in our office. It has a piston on the outside, a lot of trains and Lennox heat pumps will have expansion valves and even on the high end carrier equipment. You all have electronic expansion valves, but it bypasses this outside metering device and then goes inside and cools like normal, but when it goes into heat mode, the discharge gas instead of it, you know coming to going to the outdoor coil like it normally would it instead Goes to the indoor coil and the direction of flow changes, and when it goes to the indoor coil, so you have your discharge gas going to the indoor coil and then it bypasses the cooling expansion valve goes through. This check valve goes the opposite way. So your liquid line has refrigerant traveling in the opposite direction and then is metered by the heating metering device, or in this case it says, heating cycle expansion valve and then it goes in and now your outdoor coil becomes the evaporator coil, which then absorbs heat in So evaporator coil absorbs heat in outdoor, coil or condensing coil rejects heat out. This would typically be the evaporator coil. This would typically be the condenser coil, but then, when the cycle changes, then this becomes the evaporator coil heat goes in and then he goes out of the indoor coil, which is now the condenser coil, which is appropriate because the what a heat pump does when it's In he mode is it uses the compression refrigeration cycle to add heat to the space that's absorbed into the evaporator coil from outside alright, so we are at the outdoor unit of our heat pump system.
We're just the basic components on that are different, opposed to a straight cool system, so on our heat pump equipment, we're going to have a reversing valve we're going to have a defrost board and we're going to have a common suction. Those are the three main things that are different from your traditional straight cool piece of equipment. Here is our defrost board right here down here you are going to have your common suction port, it's kind of in between the two. I don't know if you can see that and then inside you will have the reversing valve we pop off the top.
So you can see that all right, so we have the top off here. So I'm gon na show you the reversing valve, which is right inside here. This is going to be our reversing valve on some heat pump pieces of equipment. You will see this.
This is called an accumulator here. We have our compressor our discharge line going through our discharge muffler at that points coming through here entering a reversing valve, based on whether the the solenoid is energized. It's going to direct the flow on a carrier piece of equipment if it is energized in cooling that case say we're energized it's going to come in here through here on the right side, which comes up and around here into our outdoor coil. At that point, it's a hot discharge gas running through our condensing coil, sub cooling it and turning it into a liquid.
At that point, it's gon na go into the indoor unit at the metering device go through the evaporator coil come back on our suction line. Come into our reversing valve that being said, once it comes into our reversing valve, it's going to be directed down the center pipe, which is our common suction line. The center pipe on the reversing valve is always the suction or low side. Coming back to the compressor, that's going to flow through here into our accumulator at that point, comes back out into our suction line on the compressor and heat mode. It's going to be opposite so, on heat mode, we'll go through the cycle again coming out of our compressor as a hot gas through our discharge muffler into our reversing valve, thus Illinois, it's going to switch forcing the refrigerant into the left side here, which is normally Our suction line on the line set, so our hot discharged gas, is going to go through our suction line, so our suction line out here is now going to be our discharge line. That's going to go into the inside unit. The inside unit is now going to act as our condensing coil that point it's going to cool the refrigerant down, causing it to turn into a liquid. Coming back on our normally liquid line on a carrier system, you have a piston metering device.
That's going to be right in here at this point: it's becoming a flat gas coming through. Here we are now a flash gas through this, the capillary tubes into our outdoor coil. Our outdoor coil is now our evaporator coil you're, going to have the air running over it gaining heat from the outside air. After it's gone through that whole cycle, it's going to be coming back on this portion into our reversing valve back through the center.
Our suction line coming up our suction line into our accumulator after the accumulator, coming back through back to our compressor and the cycle will repeat: okay, so here we have our defrost board a couple things to note: the outdoor fan motor hooks up to this relay. You have your low voltage controls coming in here, your safeties here and then this pink one is your defrost or your coil sensor. So this is sensing the coil temperature, letting the board know when it needs to go into defrost. If you trace this back on a carrier system here, you can see the defrost sensor connected to the out or coil right here again.
If you follow these pink wires back, that's going to be testing the coil temperature periodically once this has become frozen cold enough. It's going to force the system into a defrost when it goes into a defrost. A couple things happen. It sends 24 volts signal to our reversing valve switching the cycles from heating to cooling.
It's going to shut off the outdoor fan motor to allow the outdoor coil to defrost, significantly quicker and, at the same time as it's doing all of that we're going to be sending a 24 volt call on our white wire, which will activate our backup heating or Our auxiliary heat strips to allow the space not to cool down too quickly. Hopefully it's just a neutral. You don't gain anything. You don't lose anything depending on the kW size of the heat. Strips will be a big factor in that you.
If you disconnect the emersion hidden inside do the bills go down or does it just go into overdrive ?
If its warm outside, shouldn't be even warmer inside? Why the need for a heat pump then?..
Very helpful video – thanks for posting! 😀
Thank you so much for these videos. I struggle to pay attention, my mind will wander constantly as the instructor is teaching. These videos help me focus. Watching, listening and taking notes helps me retain the information better. Plus, I get to rewind when I become distracted. Thank for taking the time to educate me!
What is the transformer on outside unit for. Does this supply the 24V to the inside of the house as well.
Wow this is a lot. Thank you for the information very much needed
Who in the hell thought this up Are you in Kanata ?
Moved into a new-to-us house that had this system, from a home with a gas furnace, and had no clue how it all worked… now I do! thank you!
I have an 8-year-old Bryant 213B heat pump & Bryant gas furnace. This morning (at 35 degrees outdoors) I upped my thermostat from 64 to 69 degrees. The heat pump and furnace fan came on and ran for just a couple of minutes. Then, due to the call for 5 degrees of heat all at once, the Aux gas heat was initiated which makes sense. I heard the gas burner fire up and the vent pipe got hot. My concern is this: I could hear that my heat pump was still running. I learned that the 2 units (HP & gas furnace) should never run at the same time. I suppose it could be that the HP is possibly running in a different mode, such as defrost or possibly in some way that would not be harmful, but I don't know. So, I immediately dialed back the thermostat to shut it down. I don’t know how to confirm if this is a ‘dangerous’ situation or not. I don’t know if the heat pump is supposed to ‘run on’ in some otherwise safe mode temporarily. I am afraid that if I let it run on just to see if it eventually shuts down I might do damage in the meantime. The fact is that it may have been doing this all along but since I installed a new thermostat recently I am being hyper-vigilant now. I am very confident that my thermostat wiring and setup is correct. I would feel better if I knew that the HP is supposed to behave like this under these conditions. Can anyone comment on this if you happen to know?
Really help I use to always wonder how did the heat pump work, but it’s amazing how the coils make that switch. 3 main things that he spoke was reversing valve defrosting board the common suction line how they rotate depending if it heat or cold air
Thank you guys for keeping it super simple so anyone can learn HVAC 🇺🇸
I like how he just starts off saying most of us know this then glossing over it like we already know lol my dude we're here watching this video because we know almost nothing.
nice description of the systems and operation, can you clean up those wires with some wire ties so it is easier to see what the components are
Can this be used with an existing heating/cooling system i.e. existing furnace/AC kicks on in extreme cold/heat otherwise heat pump is on? Also does system have a backup so it works when power goes out? Are you in Ottawa ?
Sounds easy enough.
We need a troubleshooting sequence to figure out what went wrong with heat pumps, besides typical operation sequence. Like with furnace operation. Trace what's supposed to happen, and find the defects. Like stuck or worn out reversing valve. What would you see, how would you know? What would your pressures be like?
Love these videos. Excellent description of the system and the process.
In my experience, heat pumps do not do the job they are advertised to do. Long run times and very low heat generated. The heat strips are very inefficient, much more so than an electric furnace.
Many complaints that the discharge air is not heated enough except when heat strips are energized.
Hi my name is Jose I am from Los Angeles ca I watching your videos and I loved but you never told about water source heat pump please if you have any time to talk about water source
Thanks you for info. Do you have Books I can buy to learn a Heat Pump system better. I maintain a 12 story 151 room Hotel has the VTAC contained as one unit.
I am having 5 to 10 units crashing a year, and the Hotel is going on it's 2nd year I need to learn more about a heat pump function. I think the refrigerator tech is over charging the Hotel on service calls, with the cost of a new VTAC over $2500. I need to find ways to cut opperating costs.
I'm so confused.
Do the fans blow the same direction or do they change in respect to the coils absorbing and dissipating heat? Service area Nepean??
Jessie, lose that wedding ring before you lose a finger, no woman is worth that, LOL! Are you in Barrhaven ?
realy great info Service area Ottawa??
Heat pumps are krazy tight and mind blowing yo.
COOLING CYCLE is a just cycle in a HEAT PUMP SYSTEM
HEATING CYCLE orREVERSE CYCLE is just another cycle in a HEAT PUMP SYSTEM
HEAT PUMP is any SYSTEM that allows you to capture energy from point A and take it to point B as that happens through a thermo-dynamic process we call this energy heat
In the end of the day HEAT is only a label that we use to talk about energy so whoever is listening to us understand that we are talking about energy transference in a thermo-dynamic process
There are many other language traps in HVAC like “cold retention” and so on..
They have been around for decades!
Loved the video. It was very informative and he nicely explianed the concept practically.
Thank you for your clear explanation and good luck always
Please help! I've searched all over the internet and can't find anything relatable.. I have a heat pump system, and just replaced the thermostat as I thought that may have been the issue, but basically the emergency heat setting works, and will produce hot air, but the regular heat setting only blows cold air.. I've replaced the fuse which was blown, and have changed the filter as well. Any ideas..? My buddy said it might be the heating element or a valve.
Thank you got great information on Heat Pump system….. Service area Orleans??
Nice information guys. And since you guys put out the free videos I will do my part and not skip the commercials, only fair. Thanks.
Not discharge muffler it is filter dryer
Would like to see a video on pressure drop on line sets / sizing
Thanks for the videos, great work!!!
Please indonesian subtitle
Only 1 unit to heat a whole house ..?
Good teaching master
That was nice!
wow ! nice review for this retired old man lol ,,,,,,well done guys ! now in 2020 first day ,,my heat pump is running in north florida ,,,,,not like miami or ft laud here at all for just little over 4 hours away ! thank you
Relly nice explained
Good video. Any chance on getting a video on multimeter basics in the field?
Some of the best explained info ive ever heard. Thanks so much for the careful consideration of " wording"/ terminology because its very easy to become complacent of wording leading to a total misunderstanding of functions for those who are wanting and trying to be good techs but that are just not quite there yet. Great job guys!! Service area Kanata??
Thank you! Great info. Looking forward to more.