Hey this is Brian war, with the HVAC school podcast and HVAC our school comm. I'm doing this video in order to answer a question that we get a lot of us, which is: how do you properly test the operation of a ductless system? How can you tell that it's doing what it's supposed to do and, as you know, when you're setting up a ductless system, you set the charge by line length, you weigh it in that's the right way to do it, but you still want to be able to Check the system and make sure that it's actually delivering on the promise that you told the customer it would do it's doing the job it's designed to do and delivered capacity is a great way to do that. So in this demonstration I'm going to show you how to use test - oh smart probes to 410. I vein anemometer 6:05.

I thermal hygrometers. In order to do this on my house, I have a Mitsubishi MXZ system, which is a multi head ductless system. So I'm going to demonstrate how you can use these tools in order to measure delivered capacity, which I understand a lot of you aren't going to necessarily do, but it's a good thing to know how to do in case. You get to that point now.

Two things you need to know: CFM, that's the amount of air, the actual cubic feet of air per minute, so we got to figure out the CFM. I'm going to show you how to use the fan charts as well as how to use the vane anemometer to do that and then finally, we get to deliver BTUs. How much actual heat is being moved by this unit. There's a couple different ways that this can be done and then most difficult part is actually calculating the CFM.

So I'm going to show you how to do that from the system specs, which is generally going to be more practical, but I'm also going to take a shot at doing it actually at the front of the unit itself. So to them is the GTL 12 na that we're going to be looking at. You can see that the CFM are listed here and it's actually the same across the board for the 6000 BTU 9,000 BTU in 12,000 BTU, which is kind of interesting, because if you look here where it says, moisture removed when points pints per hour, you see in The really small unit here it's like nil, it shows nothing and then it goes up as the capacity increases, because you can see that the actual CFM the air produced from this unit doesn't change. It's the same for all three sizes.

So it stands to reason that, with the higher capacity, you do quite a bit more latent removal. It's interesting what you find when you look into the specs on specific units. So if you were to put in a 6000 BTU unit, you'd be producing the same airflow as a 12 and in turn you would have very little late and removal on that system. I thought that was just an interesting thing, but what I'm going to do is I'm going to put this into high speed, so not very high, so the way that Mitsubishi lists this is very high, high, medium low and then whisper mode or very or quiet mode, And so we're going to measure this in high mode.

You also see here that it says a dry oil and then a wet coil. So these are wet coil, CFM ratings and these are dry coil. I've had the system off so we're going to start with dry coil. Now I could use just the CFM ratings and they would be accurate, so we're going to we're going to use these, but I'm also going to use the 410.

I small vane anemometer to measure and demonstrate how that would work as well. In case you had a unit that you didn't have a spec sheet on and you didn't know what the exact CFM's were and I'm going to go ahead and put the fan to high, and that would be high mode right there and I have it set to 68, I've got the 410 I and it's already synced up as you can see here, and so I'm going to go ahead and put it on a volume flow outlet and I'm going to take a Traverse reading and I've already gone into the settings here, configure measurement. I set up the length and width, the width to 2.5 and the link to 24 inches and I'll show you how I came up with that. When I looked at this, I initially had the vanes in and then that would kind of mess up my free area.

So I had to decide whether or not I was going to measure here and kind of make this my baseline or whether or not I was going to measure on the inside, and I did a couple tests and I found out that the inside was a little Was a little more accurate? The challenge was, is that I had this little piece here in the center, and so I couldn't go all the way across in a smooth motion. So what I'm going to do is actually take the calculation in two different pieces. As you see here - and this is where I came up with two and a half so two and a half and then across this - is where I came up with the 24 inches. So actually it's close now.

I also had to figure in what is my free area. I have no calculation for free area on this, so I did a couple tests at a couple. Different speeds and I came up with 95 % for 10. I here starting on it's already synced up.

I've got it set up, as you can see here, to 95 % free area two and a half inch with 24 inch length on a rectangular and I'm going to set it up on a timed average Traverse. So I'm going to start the the vein needs to be over the surface and it needs to be as close as possible. Usually a quarter inch to 3/4 of an inch away from the point that I'm reading. So I'm going to start right there and I'm going to press play.

If you can see down here at the bottom of this, I'm going to press the play button and then I'm going to slowly paint this entire surface kind of using my finger as a guide to keep the same distance. I'm gon na paint this entire surface vein. Anemometer try to keep about the same speed. I don't have the world's most steady hand.

Then I hit pause when I get over here now, I'm going to do the same thing here so hit play again, I'm going to attempt to keep about the same speed that I did before so that way I don't weight one side over another. Another thing that you'll notice is, I set the internal veins to be straight, which is going to give me a little more accurate reading. All right hit pause, so I've hit I've hit pause here. So now I'm going to hit the stop button, see we come up with so the reading that we got was 771 feet per minute: average.

305 CFM. Now, let's compare that to what we have on our chart, we're in this range here so for a dry coil. You would expect to see 321 and for a wet coil. You would expect to see 286.

We are running in cooling, we're probably more on the dry side than the wet side, but you can see we're right in that range. I mean we're very, very close to what we're looking at, which which proves to be fairly accurate, so now we're going to go ahead and use the 6:05 eyes both of them and use it in order to measure our cooling capacity, I'm going to go ahead and Turn both on and you'll see it first still they'll flash orange and then they'll flash green and that's when they sync up and I've actually already set them up within the app. And so I put an S and an R for supply and return on them. So that I can remember, which is which I'm going to show you how it's set up in the app so one nice thing about the app is, is you can view just the basic view here which will show you the readings from all of your different devices? So showing me all three of them simultaneously just gets a little confusing if you have a bunch of smart probes connected at once, so we're going to go to cooling and heating power, which is how we're going to calculate our total system capacity.

As you can see, right now got very little going on because they're, both essentially reading the same thing and one test that I always do is I just set them close to each other and just make sure that they are pretty close, and you can see we're Within point three of a degree Fahrenheit and within pointone percentage, relative humidity, which tells me that they they're fairly well calibrated because they're reading calibrated to one another and definitely within range now, one little trick that I laid here, I'm gon na set this. On top of my is I made a, I took a ticket hanger, and I made a little bracket here from holding this, which that's a nice little factory feature it's a beach. You can add in there so that that holds that in the Airstream definitely flow. At that point, I'm going to take this I'm going to sit on top return is drawing in so I've set that thing down to 65 degrees.

So it should go to pretty much max capacity now with ductless systems. It gets a little bit confusing because on a ductless system, especially with this one, this is an NX z system. So it's a two head system. I've actually got a vertical air handler upstairs that ties up the same system.

Getting the actual factory capacity on this can be a little tricky, so I'm not even involved. This is a 12,000 BTU nominal system, and I'm just going to see if we're getting close to $ 12,000 will be to use. So first thing I need to do, though, is I need to enter in the CFM right now. I've got fourteen hundred CFM, which is clearly wrong, so we're going to go in and configure measurement and we're going to enter in what it actually specifies here on the sheet.

So we're going to we're going to say, wet coil, because now it's going to be running for a little bit, so we're going to go to we're going to go down to three hundred and sixty-four CFM's, three hundred and sixty-four CFM, it's honest on supplier. This is actual output, CFM and you can see the supplier is dropping, but you can see right now we're producing 7500 BTUs an hour we're going to let it run a little bit come back and see what we have in a few minutes. Alright. So right now you can see we're running 8,500 BTUs and what I found interesting was when, even when I had it set at 65 degrees when I set it down further, it still actually came down further because it was only producing about seven thousand BTUs previously and 65 degrees setting, I set it at a 61 and it jumped up to over 8,000 BTUs.

So that kind of illustrates why it's tricky to tell the capacity of the single air handler head on a ductless system. But it is still it's nice information to know to be able to see that as you're commissioning ductless systems. I think this is a really good test to do, because it gives you a very practical rubber meets the road standard. You know what what how many BTUs are you actually moving, and this gives you that measurement.

So if you're installing a lot of ductless systems, you can compare them to one another, especially if you're installing single head single condenser ductless systems. It's going to be a lot easier to look at the capacity tables on those types of systems that it is going to be in a multi head system regardless. We now know how much I'm going to be to use the system is producing. We also found that, at least on this particular model using you can measure air flow using a small vane anemometer with a measure of accuracy and in this particular case, I'm using a nine ninety five percent open open area ratio.

But, of course, you're going to have to for the particular brands that you sell or brings to service, you have to do a little bit more practicing in order to see what the exact settings are for you all in all, though, I think it's a good test To do in a good part of quality commissioning on the ductless system, especially since checking your charge using the traditional methods can be a little tricky, not from the standpoint of knowing whether or not charge is correct. But what from the standpoint of knowing whether the system is operating correctly, I had somebody say: well just do it to manufacturers, set up, set the charge and manufacturer specs and forget it, and that's all fine and good that doesn't tell you whether or not you have Potentially some other issues, another thing to mention is that if you create a baseline CFM, you use a baseline measurement, a way that you measure your CFM's on all of your duxelles systems. You'll also be able to tell more about how much air flow is actually being produced. So now, if I, if I use the baseline of what I measured now, if I go back to this years from now - and I measure my CFM s with an anemometer, I can see if maybe my blower wheel, becoming dirty or some other issues causing low airflow.

So I think there's some value, I'm Brian or with HVAC school and HVAC, our school comm, and this was made in conjunction with true tech tools. Comm. You can get all of these tools that I've displayed here at true tech tools, comm and you can use the offer code get school for a great discount check out.