Hi, i'm brian with the hvac school podcast and today we're at hvac school headquarters and we're gon na be talking about the KP u19, which is a mechanical refrigeration control made by Dan Voss. We're gon na go through some of the features of the control, as well as in general how these types of controls work. So first, let's unbox this we're going to take it apart. So we got to be really careful when you're working with a control like this, because it has a refrigerant filled, bulb and if you crack this bulb, then you render the thing useless.

So you got to be really careful when pulling it out just make sure you're not gon na damage it alright. So there we go. This is our danfoss KP u19 control. This is our bulb that senses the temperature.

Now one thing to keep in mind is that, while the majority of the volume is inside this bulb here, this entire tube is going to slightly affect the temperature that it's measuring. So you want to consider that, based on where you're routing this tubing, you don't want this tubing routed in a really really hot location. Otherwise that will affect the reading of the thermostat you're able to get a lot of really interesting information. Just off of reading the box - and actually this is one of the things that I recommend to new technicians - look through to see if there's a spec sheet in it and then just read the box itself.

So it's a temperature control. It's a thermostat. The range is negative, thirty degrees Fahrenheit to eighty degrees, Fahrenheit. You have a differential minimum differential of plus 3.6 and a maximum of plus fourteen point six, and then this is a 120 inch capillary tube and this contact type is SPDT, which means single-pole double-throw, which means it only has one pole that shifts in between both sides.

But it can either be open or closed depending on whether not the switches above or below its target temperature before we go any further, let's go through the manual so as a lot of benefits to it, easy to use very durable design. Now you've got three different: KP u19s you've got one, that is a single-pole double-throw, which this is the one that we've got here, where it has two different terminals on it, where you can, where it makes our brakes in either direction, and then we have another version Which is a single pole, single, throw which means that it's just open or closed, and this would be sort of your traditional, a very simple value: refrigeration control type. So this is a just a closed on a rise in temperature, which is what you want for a refrigeration or a cooling type application and you've got the third one which does not have a bulb. It just has just a tube, and so it's designed for measuring temperature in a room or the air on a coil.

It's not meant to be mounted to anything. So you're not you're, not supposed to mount that to the coil itself. Where is the bulb version? You can mount in the Box where you can also mount it to some some copper tubing to the coil itself. It comes with a censor, clamp comes with the blinding stickers, what they call it and that's to kind of blind it off, so that it can't be easily changed without somebody getting a screwdriver.

So your customers, don't don't monkey with it, but here's the here's. The thing I wanted to show you the H terminal on the one we're working on, because we have this single pole. The pole is the part that moves and the throws are the two points that they connect to single-pole double-throw design. Here it is connected from C to H when you use it in a refrigeration type control where you want it to shut off once it gets to temperature and because then it would drop and and break that circuit.

Once the temperature drops the other side, the L terminal will then make once the temperature drop. So once the temperature drops below the setpoint, then it will actually make 2 L. And then you have your single pole single, throw open on low, which is just once the temperature gets low enough. Then it opens and shuts unit off.

That would be a very simple low temperature, cutout type of thing, and then it could also be used as a as a fan. Cycling control all right. So here it shows the different elements of it. You've got your capillary tube.

You've got your conduit rubber, which is where the the conduit can come through, either through the back or through the bottom. This is the differential temperature adjustment knob, which, again, the total differential, is going to be double whatever you set on the knob, and then you have your actual temperature setting and as well as our mounting holes in the back of the in the back of the control. So you can mount it properly to a flat surface, which is how it needs to be how needs to be mounted, and this needs to be installed in a dry location. It is designed for a dry location, alright, so let's go ahead and take a look at how it works alright.

So what I use is, I use this ice bath, which is a really nice way of comparing your thermometer, making sure that it's with gin in general within range we're within a degree of 32 degrees here. So I feel pretty comfortable that we're measuring pretty close. So I'm gon na place this into the ice bath, trying to be pretty gentle with the with the tubing and now the fact that it's not all in the ice bath. All the tubing is not in.

There means that it's going to read a little bit on the high side, so this arrow up here is actually what points to the temperature which it changes. And now, when I test it, I'm just going to connect one of them to common and it really doesn't matter which one I connect to, but we'll just start by connecting it to the low temperature. You can see right now, where I have it set based on the low temperature set of contacts it will. It will be running because it's warmer than the actual set point so now I set it down all right now, we've gotten cold enough that now it's saying! Ok, we're good we're shut off so now, at this point, it's saying that we don't need to run because the temperature of the ice bath is below the set point on this thermostat.

So as soon as I roll it up alright, now we want it to come on 40 degrees off now. This is gon na be more like what we would use for refrigeration control. So currently I haven't said at 40, it's off its off its off its off. Until I get down low enough all right now, right at about 32 degrees, that's when I cut in cut off at about about 38 cutting in at about 32 33 in that range, which is about exactly what we want now when we adjust this differential right now.

I have it set all the way at the minimum differential. So if you look right here, you can see differential and it's set at minimum. If I roll this back, that's going to greatly increase the cutout. So now, let's see what we get so now we're gon na now it didn't cut out until 42 in that range and now, let's see where it cuts back in all right.

So now it cut in at more, like 28 cut at about 38. So you can see that with this one, based on how it's set up right now, with the bulb in the water that we've got 32 degrees is sitting about right in the middle of that range. So you got a got to set. This up got ta, make sure that you get your differential and your temperature setting exactly as you as you see fit, and then you can use that little blank off sticker that we showed blank this off, remove the knob and then that way nobody can adjust it.

Unless they take the cover off, which is a pretty nice feature, I'm Brian with the hvac school podcast, making this video in conjunction with our friends at dan Foss dan Foss engineering tomorrow today, thanks for watching.