Latest / The Refrigeration Mentor Podcast / Episode 353. Understanding TX Valves (Tips and Troubleshooting)

Transcript

Episode 353. Understanding TX Valves (Tips and Troubleshooting) · The Refrigeration Mentor Podcast

• 0:00
  Speaker: What's up everyone? Trevor Matthews from Refrigeration Mentors. So happy you're here. I wanna dive into some technical topics today. I want to dive into a, conversation. I've been having a lot in the community as well as in the supermarket. Training is TX valves. Like one of the big things is, is there's so many TX valves out there.
• 0:01
  Adjust your super potentially when you have a parallel rack and a multiple compressor application or multiple system application where. You might have to run lower super heat on a circuit to make sure that your compressor doesn't run super hot. Your compressors. And this, this here was very interesting to me because I've not really had someone explain it to me this way.
• 0:02
  Because in a lot of the new application with these newer refrigerant, just like R 22, you needed to use something like refrigerant injection or demand cooling, if you ever heard of that. And basically what that is, there's a sensor either inside the compressor sometimes it's on the discharge line, sometimes it inside the, the top of the scroll, depending on the application.
• 0:03
  And this comes back to the TX valve conversation. We use these devices to make sure we cool down. The compressor to make sure that we don't overheat 'em, trip them off under internal low overloads, really start to break down that oil when we get too hot and lose lubrication. And this was the conversation we were diving into, which I thought was so, so interesting in these applications.
• 0:04
  Now it's too hot. Okay, and just say you have all your low temp valves and all your systems set up for say, 2K or four degrees soup breed, or three K six degrees super heat. At the evaporator and you go all the way back to that compressor now and you're running that, say that 38, 39 k 80 degrees, 85 degrees Subaru, you're outside the envelope even though you have all your evaporators set up accordingly.
• 0:05
  You, you're gonna pick up. Soup eat. This is a non-useful soup. Eat anything after the evaporator. Soup eat is non-useful. That is just picking heat up, putting it in the suction line, and or putting it in the refrigerant. And bringing that back to the compressor, and you don't, you don't want that because that there is going to reduce the efficiency of the system.
• 0:06
  Spend that more money upfront, get it done right, get some fine tuning done over the years, and you would save a lot of money in the long run for sure. And why is, why does this come back to TX valves, expansion valves, thermal expansion valves? Soup breed. Well, we gotta understand how to set that up properly.
• 0:07
  Because that's, that's really important. Or how do I check it? Sorry. How do I check the size of the TX valve and does it match up? Well, realistically, you gotta know what that evaporator capacity. If you're in bts, if you're kilowatts, if you're tonnage, it doesn't matter. You need to know that. But you also need to know some of your design condition.
• 0:08
  Are you getting that same temperature from the receiver all the way to your metering device? So you would take that temperature and you would plot that in the different manufacturer's. Tx either software like Danfoss. Cool. Select two. Sporin Virtual Engineer. White Rogers has one, or Copeland has one, whoever it is.
• 0:09
  Because you get more capacity with the lower temperature liquid going into it. Now, if it's a higher temperature coming down, you'll. Need a bigger valve. So this is just getting into sizing, and you should understand this because you can run into a situation where you're, you're undersized and you're not, you're not making temp or you have a higher back pressure or suction pressure because you're not getting enough expansion through that valve.
• 0:10
  There's so many different options. So us. Understanding each one of those is gonna only make us better. So now getting back to troubleshooting, one is that we need to know if it, if it's sized properly, then we need to know how is it working? Is it working accordingly to the way we set it up? 'cause one of the questions wasn't in the community.
• 0:11
  'cause there is lots of things going on out there, especially with retrofits, which is huge. You know, you retrofit from R 22 to 4 0 4 to 4 4 8, and so on and so forth. Now you had that same original TX valve that was put in there 20 years ago. That may have an effect and that may, it will have an effect on the super heat for that coil.
• 0:12
  When do you set it up? I want you to think about that. When do you, when can you set that TX vet up? Yes. When you're close to actually the set point. So you need to set it up, close up within a few degrees of that set point. That's when you set up the TX valve. So then what's next? Well, I need to check it after a defrost.
• 0:13
  So it's gonna have a different velocity and mass flow through them versus in the middle of the winter when you have way less pressure or SCT or SDT. So that makes a big difference on it. And this is where you'll see swings in in your TX valves. Not big swings, but you'll see it and it'll go up to a temperature down.
• 0:14
  Clean. The condensers are clean. You got the right fan motors, everything's running on it. The VFD is running. If it's our ECM fan motors are staging properly. The compressors are turning on, turning off properly. You want to make sure that the, the TX screen is not dirty or the filter dryer, B floor or the tx screen is not plugging up.
• 0:15
  If I've was never taught And that, and that's totally fair. So this is where you gotta go back in and get your engineering hat out as a technician and find out where. Those conditions are supposed to be. So now in a supermarket application, we talk about this all the time in our supermarket academy supermarket program, CO2 programs, is that you need to get that refrigeration schedule inside and on that refrigeration schedule, it's gonna talk about your.
• 0:16
  You're gonna have the capacity of your, your high side, you're gonna have your SST, your low side. A lot of the times you're gonna have your liquid temperature going out. So all this information is right there, and your refrigerant's gonna be on there. So this is how, and you can take that information and just size, okay, in circuit one, this is what it should be.
• 0:17
  And you take all that information and then now you can, and you know the refrigerant and now you can, that's useful information for you as a technician. Now you can use that information to really help you in your troubleshooting scenarios. And this goes back to that. TX valve. So now I look at the unit, these are the conditions I should be running at.
• 0:18
  This is how I see so many technicians just crushing Supermarket Academy or who comes through the program. It's 'cause they're looking at the bigger picture. Now versus, well, we're just looking at, oh, there's this oil issue, but that oil issue could be caused by two or three other different things that have nothing to do with the oil.
• 0:19
  I've had multiple people come into the community, community and watch some of the videos on the, in the supermarket academy after they took it. And they, they, they told me, man, because of this video, like checking the temperature across the check valve or checking the temperature across the so night or checking temperature across the filter dryer.
• 0:20
  It could also be from the condenser unit, so the condenser on the roof, say for an example, has a fan. Banging on. Banging off. Now think of what happens to your system, your high side pressures when you have a fan. Bangs on, bangs off, bangs on, bang on. Especially when it's cold outside. It doesn't matter if it's really hus the same thing.
• 0:21
  And this is an issue because that changes that liquid quality. And then what else do you have happen? Well then you have in a system that you have flooded valve, you have that a eight a nine valve engage, and then it disengages, then it engages and disengages depending on how low the pressure goes and how long it goes there.
• 0:22
  Are we running to, to spec? And, and one way to check is just, you can do a, a compressor efficiency set test as well. So look at what your specs are supposed to be. Get your gauges, put them on the compressor, your discharge, your suction. Get your temperature on your suction, your temperature on your discharge.
• 0:23
  Because a lot of times, anything that happens within the system is gonna affect that compressor. And the compressor has so many data points. We, we may, we may not take them all the time to see what that temperature of those heads are or what temperature of the oil is, or what does it look like in the site glass.
• 0:24
  'cause mostly I worked on Copeland Mo most my career there was some Bitzer and there was some Carlisle screws and there, there was a few other manufacturers that I worked on. Like tecums and then little small Hermetics, but on the supermarket it was mostly Copeland with a little bit of Bitzer. But there's so many other compressor manufacturers out there that I know of today that moved into North America, or especially with CO2, but it's just understanding that getting those data points will affect what you can plot it, and whatever that tells you it is, that will give you an idea of, is the system running normally?
• 0:25
  They're all inputs. It's not. That important to understand if their inputs or outputs. But what you wanna understand is really how it opens and closes. And we know the discharge the bulb on the outlet of the evaporator is going to tell that valve what to do. So it's gonna say, Hey, we are really, really hot right now in our suction line.
• 0:26
  The pressure starts to let off in the bulb, lets off that diaphragm and then starts to. Not open as much. It reduces the amount of refrigerant going through, so we start to start to increase the temperature at that outlet. The problem is, is that when you get into a situation where the TX valve is either maybe oversized.
• 0:27
  So there's a lot of different things that you wanna look at before adjusting the tx l. And don't get me wrong, it could be someone could have adjusted improperly. Before, but a lot of the times, if it was running okay for six months, one year, three years, and now all of a sudden it's not working properly, usually it's not the adjustment of the TX valve.
• 0:28
  You pull out the, they pull out the whole charge, they put a new TX valve in, they charge a back up. They set that, that new thing, oh, it must have been the TX valve, but actually it was the charge that was the issue. And they pull out the charge and they recharge it with the proper charge, and now all of a sudden it's working.
• 0:29
  Like the bulb had to rub through and you didn't, you didn't see it and that was the, the problem and you had to change the power element on it or something. These are just a few tips on troubleshooting TX album. There's, there's lots more. I know my friend Andre Patau, he's wrote a guide like 20 years ago.
• 0:30
  It's just, just building that knowledge up and continue to see new things and more things just to make it easier for us. And to really pass that knowledge on to others. And that's, that's the step, that's why I do a lot of these training programs, is to help more technicians uplift the industry. That supermarket academy, that's just crushing out there more and more technician to tell, reach out all the time.
• 0:31
  So refrigeration mentor.com/hub and join the community. There is so many great professionals in there who want to help level you up, really help you be more proficient if you want to. Up your game. And that's what it is, is how do we help each other grow? 'cause I am learning every day from the technicians in the hub.
• 0:32
  I, today was real technical, but it. It can't be just personal development, some of the goals that you want. I want to be an expert at TX valves or electronic expansion valves. I did a podcast a week ago with a control expert, and they've been doing it for 30 years. It takes a long time to be proficient on controls, but one of the things he said, like the top control experts, it doesn't matter to controller, it doesn't stress them out.
• 0:33
  When you understand the, those fundamentals and you understand how to actually interpret what the inputs and outputs and, suction setup and condenser setup, that stuff is so, so important because they all, they, they all have to do it in a similar way. You need input, you need to be told what's happening.
• 0:34
  This is how we all grow, is helping each other get to the next level. And. Our careers. Super excited that you took the time to do this, and as always, let's get a conversation going.