This video is brought to you by sportlin quality, integrity and tradition. All right, we've got a reaching cooler today that um obviously is frozen up, but they're also complaining about it. Freezing all the food on the top notice, how they're double panning stuff, so they actually called me about that they didn't even bring up that the bottom wasn't working. Maybe it is, i don't know, but it's all frozen, solid, so um, even though there's two separate temperature controllers, they work together, meaning that um, if uh it just depends like this particular one right here.

The this is a pressure control, okay, that pressure control controls the temperature for the top section. The way that it works is it also works as a low pressure safety. So whenever the bottom is running, the top runs. So if the bottom is iced up and it's constantly trying to bring the product temperature down, the top is going to continue to run and run and run it's just kind of a silly setup.

I, like the ones better where they have two separate temperature controllers for the top and the bottom, but regardless they also have a defrost timer right here, that's actually just an off cycle timer and that's only for the top. So that way, it does a shutdown from midnight till 8am in the morning that just shuts off the top they're not supposed to be leaving any food in the top at nighttime. They take it out, they put it in the bottom, so we're going to start by defrosting the bottom that very well could be our problem, but we'll investigate more. Sometimes people get back in here and they start adjusting on this pressure control things like that.

So we'll check everything so yeah the ice is super thick. I just got my pump spray right here, which is some hot water in it. We're just melting it as it's draining or looks like it might be draining. I don't know, maybe it's plugged up too we're just melting it slowly and then we'll get in there and check the sensors all right.

So we got the unit put all back together. It's operating! It's all defrosted. We have our probes on it. We're checking the refrigerant pressures.

They look to be okay, we're looking for about 25 to 30 degrees over ambient temperature um. Let's see it's 35 34 degrees in the box right now. It should be shutting off here any second 73 in the building 83. 93.

103. Condensing temp suction pressure's, about where i think it should be now when we had the coil apart, we tested the sensors in ice water and they owned out at about 16 000 ohms, which is about where they'd be or 16k ohms. But then what i noticed is now i use this for troubleshooting purposes. If you don't know you can do this, you can throw a display on a control that doesn't have it and we're reading an e2 error, which is an evaporator coil sensor, which is the blue one, but it tested fine.

So that's interesting because it tested where it should be. It looks like the unit's pumping down right now, so we're gon na. Let it we're gon na see where it turns back on at just to see um, but i think we're gon na have a bad temperature controller, because the sensors tested okay, they owned out where they should be and we're still getting that e2 error. And it's weird, because if i unplug it and plug it back in it'll go away, and then it comes back after a while all right.

That's weird! Because now i plugged in a good sensor and it's reading 34, where it should be and we're not getting the e2 error, but this guy's omin out. So i don't. I don't get it. I don't.

I think there's still something wrong with that control, regardless we're gon na end up changing the sensor and then we'll probably change the control too, because this is funky for sure all right, i'm all over the place today, but i decided just to change the sensors for Now, because we're gon na be coming back with a drain pan and we'll check on the temp control, then okay go ahead and pull. Tell me when you get them go ahead and untape them. So i have someone on the other side pulling them back through and then we'll pull out the old sensors here in a minute, all right, much better got the sensors replaced, got them tied in there back there ran up into here. You always tie a knot so that way they get stuck and don't pull out.

So we just have this display, and i don't know if i explained enough earlier so this display is just temporary. These controls can accept a display. Sometimes they have them. This one happens to have an analog one, but to make your life easy, you can plug in a display to one of these controls and it'll still give you error, messages and temperatures.

So earlier with the old sensors, i was able to confirm that this was accurate and it actually still is 55 degree return. 54. That's i'm happy with that. So we're waiting for the delay and then i also adjusted on the pressure control, because that is our temperature controller for the top.

If i didn't already say it, you got a temp control for the bottom. You've got a solenoid valve for the bottom. You have a solenoid valve for the top - that's controlled just by this defrost clock and then also whenever the bottom is running. The top is running because it uses this low pressure control for the temperature control for the top, so that low pressure control is also a low loss safety whenever it runs out of gas.

It shuts down the system too so kind of a weird design, but because this control wasn't working right and it was constantly icing up - the box was constantly trying to bring the bottom down to temperature. Therefore, it was freezing the top, because the top always runs whenever the bottom is calling, but if the bottom satisfies the top can still run until the pressure gets to where it cuts off for the top at the right temperature. If that makes sense, so del field is the manufacturer of that unit, and delfield makes two different styles for this box. They make the style, where there's two separate temperature controllers, two separate solenoid valves where a temperature controller independently controls each section right.

You have the cold, rail and the base section. Then they share a common condensing unit, this particular style. The bottom section has its own control, as you guys saw, and that's what controls the bottom. But then the cold rail has a defrost timer or an off cycle.

Timer, it's not really defrost! It's an off cycle, timer that shuts the unit off on the top. You are not supposed to leave the top running on these cold road units. They need off cycle because uh, if you've ever seen these before, if people don't use the off cycle, what can actually happen is uh. Condensation can slowly start to build up in the cold rail cavity and over time that condensation will start freezing and it'll start destroying the inside of the box, plus, on top of that, if you think about it, you have frost and ice right ice acts as an Insulator, so once you start getting enough frost and ice up on that cold rail, it starts getting thick to where the pans can't fit in there and stuff.

It actually brings the temperature of the cold rail up to 32 degrees and 32 degrees on a static cold. Rail is not going to it's not going to work right. Typically, on these cold rail units, they run the temperature down to typically between 13 and 17 degrees. Air temperature, underneath the pans with the pans, fully sealing everything in order to maintain a 40-ish degree product temperature.

Now static cold rails are not the most um efficient way to cool the food up in the top, and something to understand too is that reaching coolers in general they're meant for uh product storage. They're not meant to bring product down to temperature, so the customers can't be loading warm food into these boxes. It will ruin the entire unit's efficiency and if they start putting warm food in there, they will start seeing issues. In fact, i've got some a customer where i just had this happen, where they've their cold rails, uh they're, not working right and they're like it's always too hot, you know well, what's happening, is they're set up to turn off like they should be at night time, But the customer wasn't removing the food so therefore the cold rail would get up to 45 50 degrees and the food would get up to 45.50, but then it would automatically turn back on at eight in the morning.

Well, then, the box could never recover and it starts affecting the entire unit when that happens, so understanding how these units are supposed to work is so important and as service technicians oftentimes, because the manufacturers, especially when you're dealing with like chain, restaurants and stuff, the manufacturers, Do not do a good enough job of educating the customer on how their equipment works, so it doesn't matter what manufacturer you tend to find this, especially with corporations. Someone in the corporate office knows how this box is supposed to work, and someone in the corporate office knows that they're supposed to remove the food from the top every single night, but that is not passed down. Okay, now the reason why i say the manufacturers are not doing a good enough job if you think about it, really, it's the corporations, the restaurant's fault right, but the manufacturers are the ones that are getting the black eye from this. So, that's why i say it's the manufacturer's fault, because if the manufacturers themselves did a better job of training, the end user on how to use their equipment, then, even though it would take extra effort from the manufacturer, it would actually make the manufacturer look better.

In the long run, okay, but regardless, i want to stress the importance of understanding proper sequence of operation, and i also want to dive a little bit deeper into that pressure, control that is controlling the temp for the top section, okay, so to clarify the bottom section Has its own temperature controller right and the top section runs off of that pressure control. It's using the theory that at any given saturation temperature right or any pressure there is a corresponding saturation temperature of that refrigerant. Okay, so on the side of my wall, you guys can kind of see. I have a pressure chart right here: okay and that's going to tell us for every refrigerant at a certain pressure, it is a certain temperature okay.

So using that theory, if we know we want to control the temperature in a static cold rail like we have up top that's using convection, okay um, we know that at a certain pressure that is a certain temperature. Okay, that refrigerant is and there's some uh heat transfer, that's going to happen in there. So, therefore, if we set the pressure control to cut out at a certain pressure, the refrigerant will be a certain temperature. Just like i said i know it sounds like i'm repeating myself, but we need to drill that into people's heads.

So in this situation that pressure control acts as a temperature controller and as a low loss safety. If the system ever ran out of refrigerant, it would shut off the compressor, but at the same time it will keep the compressor running on the top section until it gets to a certain pressure which corresponds to the temperature at which they want the refrigerant to be To have the proper heat transfer to keep the food in the cold rail at a certain temperature. Now, clearly, you guys saw the flaw in this one. We had a failed temperature sensor that wasn't working right.

It caused the bottom to consistently run and froze up the bottom. Now that ice, like i said, starts to act as an insulator, and then the bottom section will start getting warmer and warmer, but because the design is set up to where the top section runs. Whenever the bottom is running, the bottom is never going to shut off. So it's just going to be a vicious cycle and then they're going to start freezing the food in the top section right and that's what the problem we were having this one with this one.

So um understanding and really thinking about the operation of these boxes helps you to be able to troubleshoot. So i knew right off the bat. When i opened up the bottom section saw it was frozen up. It's like you know what more than likely that's the cause of why they're freezing the food in the top, because i understood the sequence of operation and how this unit operated.

Okay, you know, i don't understand how every single unit that i walk up onto operates right. I have a general understanding of basic refrigeration and i have some experience from making a lot of mistakes over my career. So it's easy for me to walk up and say: okay, this seems like a basic unit, but i always still will give a call to the manufacturer lean on them, get on the phone with technical support and just kind of pick their brain. What's the sequence of operation, what's your control strategy, what kind of temperatures are you looking for and then it's really important once you do find that information out write it down, write down what the operating pressure should be write down, what the temperatures typically should be because If you work for like chain, restaurants like i do you work on a lot of the same stuff, so you don't have to keep calling the manufacturer every single time, bogging up their tech support phone lines right, so i reserve the right to or i reserve my Phone calls to them uh for stuff that i truly need once i've gotten information, and i write it down, and the cool thing is that we have these really cool things in our pockets, right that have all kinds of apps that we can store information on, and We can put, i have a note app in here and i'll put notes in there.

Dell field refrigerator operating pressures, manufacturers suggested cut in and cut out of pressure controls, and i put it all in my phone so that i don't constantly have to lean on the manufacturer and call them for silly things repetitively over and over and over again. Okay. So i'm not a perfect technician, nor will i ever be, but i'm always striving to be the best that i can that's that's all that i can do is just try my best, so i encourage all of you guys to do that, and i encourage all of You guys to share that information once you do gain it so that way, maybe you can help another technician and help them to not have to make some of the same mistakes as you do. That's the whole premise and what my youtube channel has become.

I you know i started making these for my employees. It turned into something else. I hit the public button and i just share my experience, my mistakes and my success stories. That way, maybe you guys can have the same success and or not make the same mistakes as i have okay.

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