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This conversation is a deep dive into RDM controllers with Kevin Mullis, Head of Product Engineering at Clade Engineering Systems. We discuss key considerations for setting up and commissioning these controllers, including probe placement, transducer settings, and parameter adjustments. Whether you’re dealing with new installations or troubleshooting existing ones, Kevin has some super valuable insights to help refrigeration technicians ensure your systems run smoothly and efficiently.
In this episode, we discuss:
-RDM controllers overview
-Initial setup and probe placement
-Controller power-up and network connection
-Configuring and testing probes
-Advanced controller settings and troubleshooting
-Understanding valve parameters
-Superheat problems and solutions
-Minimum opening settings
-Manual reading importance
-MOP configuration
-Fan management settings
-Temperature alarms and probes
-Defrost settings and procedures
-Commissioning and troubleshooting
Helpful Links & Resources:
Episode 281. CO2 Experts: Troubleshooting CO2 Systems using RDM Controllers with Kevin Mullis
Episode 246. CO2 Experts: Startup and Commissioning with Kevin Mullis
Episode 227. Getting to Know Transcritical CO2 Supermarket Refrigeration Systems with Kevin Mullis
Kevin Mullis on LinkedIn
Website: Integral UK Ltd.
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Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
(00:00):
Welcome to the Refrigeration Mentor Podcast. Hope you're doing well. We're gonna be doing a live demo today with my good friend Kevin. He is been on the show many, many times diving into controllers. He is the CO2 expert. And yeah, as always, love that you're sharing comment on this stuff. Just if you're getting some value from it, please share it with someone.
(00:01):
All I had was some quite old ones in the garage. And I reached out and they put me up with a new one. So thank you very much for that.
Yes. And as we said, a lot of the things that we'll do here, even though they. Geared for IBM in this case, we'll apply across the board with different controllers and yeah, the setup on the front end will be different, but the steps you take to do that case or do that cold store are pretty much the same for all different systems.
They'll put the defrost probe and your coil, inlet and coil outlet probes in the end of the coil. Usually. Now if you've got a really good electrician, they might fit the probes for you, but I'm not a very trusting guy with probes. I'm gonna go and have a look and I'm gonna see where they are and I'm gonna make sure they're secure, fixed on the pipes.
If it's a small job, you won't. If it's cabinets that you're doing, am I gonna take every case of partner check where every probe is? Probably not because I would love to, but in reality, if I've got 20 cases to commission, that's a hundred probes to check potentially, and I'm not gonna have time. What I'm gonna do is if I don't dunno that brand of case, I'm gonna take one, two bits and I'm gonna check where the probes are.
When your case fitters come along and bolted all cabinets together, they're gonna remove the fan plate. And what's gonna happen is the fan wire's gonna be stuck in the back of the blaze. And when you switch that on, you're gonna get DA and you are gonna think, oh no, it's chewing through the wire, so I'm gonna do, , it's true, right?
So if it's RDM, there's several different ways we might be going online. RDM likes IP as it's main networking. It will also do RS 4 85 and you can connect, if it's on ip, you can go different ways. You can go through a hub. The RDM will supply you and you can have multiple fixtures in there, in which case some of the addressing is done for you.
If you short those two connections together, you're gonna break in the cable somewhere near the panel, you are losing the lot. IP is more resilient to that. You, yeah, you can have, start, have one cable from the where panel is to all your fixtures, but you gotta be extremely unlucky. And if you lose everything, , it's that cable.
And you just because the cable looks the same, it doesn't mean it's talking the same language. So, on an RDM controller, like this one, the socket on the side is a category five socket. Regardless of what type of network it is, this actual one plus out two, three. Two. So don't be fooled by the type of cable it is.
And that was the way we used to do it. Everything on RDM before they put direct IP into the controllers. So you have options, but just because it's the right type of cable doesn't mean it's ip. You've gotta check what type of network it is and you, you've gotta know what you're plugging it into.
A couple of things to point out on here where it says NC on the mains, NC means not connected, not normally closed. Don't put anything in there on the relays. It's exactly as you would expect normally closed. Normally open and common. Okay? They're all vault three relays. Down there. So you've gotta put a supply onto them.
It's this is their RD m's front end. Fantastic piece of kit. Makes everything nice and simple to use. I've had a lot of devices logged on here in the past. My new RDM controller, which I've just powered up, is that one. So all I've done for that is I've gone into the controller network menu and there's an option called id and it's a three digit number and I've just picked any three digit number to put in there.
Mm-hmm. So, because I'm, 'cause I'm going ip, I have my module and I have my three dials to set an address right there, right? So it's hundreds, tens of units. I'm just gonna set number one to three and we'll see if that logs the sun. I'll plug it in. If it doesn't go bang, it'll be a sweet miracle when I can let the power up and we'll we'll go for it.
Now, there's a menu on the RVM controller that called type. You've got types one to six on most of their controllers, and that gives you presets, right? So that will give you whether you are on a case, let's say. Or a cold store, it will give you certain default options. Like do I want fans on in defrost? Do I want a door switch?
Like a month. It's never 43 degrees in the uk it's 43 Fahrenheit maybe. Yeah, yeah. So I'm immediately thinking when I see that, am I on the right range of probe? Because RDM supports multitude of different probe types. Read the manual is what I would advise on that. And just check your probe types.
There we go. So, so number 300 there is the controller that I disconnected. So that's a big, pretty good demonstration with RDM of how robust it is with old controllers that my data manager is about 18 months old. The controller I've just connected is well over 10 years old, and all I've done is put an address in it, connected it on, and it's appeared.
So I'm happy with that. They're all saying virtually the same, which also is good news to me because if I've got three, say in 25 and one saying 35, I'm saying they're all in a room together. Why is one much higher than the other? I also notice from that I've got a suction line probe fault, right? And the controllers flash in P prb four on the front.
Brilliant probe falls out very easily. So the next thing I'm doing is I'm going chasing that fault and I'm gonna put that wire back in. So I've got all my probes reading at that point, I'm happy they're all saying the right thing. I'm not gonna do it now. I'll probably get electrocuted from my dodgy setup.
It's gonna be quite a tinny little sound, and I'm happy then that my valve's working. One thing to note with RDM if is where, if it's a mechanical valve with a solenoid, it is wired fail safe. So on the back of your controller, it's wired to normally closed as are the fans, right? So check your relay one, your relay two wired normally closed.
Which is which is what we all wanna do. I'm also gonna be looking at my transducer if I've got a transducer fitted. Now what I'm gonna bear in mind is if I'm on vacuum and it's not a minus one, two something pressure, , let's say a thousand PSI, if I'm that 200 bar, whatever. If I'm in a vacuum and it's not rated to minus one, I may be showing a fault.
So I'm gonna be checking to see if there's a reading on that. I'm not gonna worry too much if it tells me when I come to set it up that there's a fault with the evaporating temperature because RDM knows that you ain't gonna operate this below the triple point, and I wouldn't be worried about the reliability of that reading until I've got pressure in it.
You get then to what you're getting on the rack or what you're getting on your gauge, depending on where you got connected, and go from there. Yeah, it, it's it's one of those where you can easily start chasing a faulty transducer only to find that you just need to put some pressure in it and it'll be fine.
(00:22):
Your case manufacturer is gonna tell you what you want on that RDM percentages hub. Your number is the percentage of the error on, right. So if you set that to a hundred percent that is reading a hundred percent of the air on IE exactly what the error on process says. You said it's a zero, it's reading a hundred percent error off.
Cold stores usually. A hundred percent air on because you wanna read the warm part, right? You wanna read the air going back outta the room. That the only time I would deviate from that on a cold store is if you've got, let's say, a dual discharge cooler in a teeny room and you've got a really bad situation with air bouncing around the room.
Of the controller to what it's controlling against. So that one will be how the thermostat operates and that one be what shows on the screen. Right.
Air on is the air is er, air return air. Just wanted to clarify that. Right? So we get the return air, air on, that's the air going onto the coil air off.
It will, it will eventually end up at the air on and you'll get those two values reading differently. There'll be 31 Celsius now and tweet. Yeah. So when it eventually updates the, so there we go. Right. It's got a grip of itself now. So you see it's reading all of the air on value. Yeah. Whereas before it was reading an average of the two.
Right. So, and this, this is how we check the probes as well. All I would do in a cold store, I would have somebody holding that probe and I would watch what the value did and I would then check, because I know it's the error on probe now because I've seen the, the number go up. And it's worth saying if you, and good point you make about the, the probe settings and what people call them.
We can do that with any input, any output, any parameter, and any alarm. So if we want to call things, classic example is cold stores. So RVM calls all its alarms case. Even if I change that to, to a cold room, it'll still say case over temperature when it alarms. But I can do an alias change through this panel and I can change that to say, cold store high temperature.
And then we'll, we'll know what that fixture is. It will, it'll eventually update. That's my fault. Okay. There you go. It's updated now and I'm going a little fast for it. Okay. So in our parameters that we're gonna do, other than that alarm weight, so you might not want it. To alarm on air on or air off?
You then got your EV settings, 'cause it's an EV controller. You can set your super heat reference in there. Six is a good starting place as we know. If you need to turn it colder, you need to turn it warmer, you can do it from there. Response on and response off is how fast the controller responds to the super heat changing.
And what, yeah. And what we know we all know very well is that. Everyone loves to see PI and D there, but actually quite comparatively, few people know what PI and D actually do.
It wants to keep trickling some refrigerant through it, so you've got a chance of rectifying itself. If you'll use the transfuser and it sees a super heat fault, you'd set that to zero, not a problem. And it'll then wait for its its problem time and then it will try and start the valve up again. And that's useful if you've got a brief issue with the rack that you've solved, and then the case will get away by itself.
If it gets below that limit, it's gonna go into problem. Yeah. And depending on how you shut set that, it's either gonna shut the valve or it's gonna keep the valve a low level. The problem when you are only controlling on probes, if you are not using a transducer to get your inlet temperature, your evaporating temperature, if you shut the valve completely, you may, if let's say the coil's absolutely clear and you've just had a rack issue, when you start it up, it may struggle to get away because you've not got any temperature sense to the inlet.
I think it's important too, read any manual, but for an example start opening percent. That's gonna be different if you're on a chiller versus a long run cold storage. 'cause if you, you have that at 75% open start opening and you're only two feet away from the compressor, you're gonna be in some trouble.
All the start opening is therefore is to let you stabilize the super heat. Yeah, it comes, it comes from a time when we didn't use transducers. Really, in all honesty, it's just about settling the super heat down. But one thing I will say, just as I say about reading the manual, I know nobody enjoys read reading.
let's talk about the, like maybe the six or seven. 'cause there is a lot that you're showing there, but what are like six or seven on like, MOP is a big one for sure. You,
After the MOP delay, it will shut the valve by whatever percentage you've set that diviv value to, which is a parameter away at the top. So they are value. So if I set MOP to, let's, let's say it's CO2. Let's say I set the MOP to 40 bar Yeah. 600 PSI, whatever it is, it will, if it hits that and the time elapses, whatever percentage the valves at, it's gonna half it you, if the valves at 50%, it's gonna set it's 25%.
You can ask the fans to stop when it stops cooling. You can ask, ask the fans to stop on defrost. This is one to read in the manual. The app, so you can set fans that, for example, fans temp mode in there to temp, and then if you get to that temperature, it'll switch the fans off. And this is stock protection to a degree.
Because if you've switched the fans off, you can't sense the temperature accurately. So it will bring the fans on every often to do that. You can tell it what prob five does in this case, it's defrost. You can set it to be monitoring as well. You can tell it where the lights are. This is where you tell it, how am I sensing my evaporating temperature?
Switch resistors, that's a, the useful one. So you can tell the controller by putting a resistor across some of the probes to put itself into fan only put itself into lights only. You can tell it to do a defrost. You can tell to lots of things with the resistor across the controller. Again, explain to the manual, but if you want that function, you need to turn it on and then.
You can set two different temperatures and that will switch between two. Or you can tell it, if I see that input, I'm gonna go into defrost. That's quite useful for things like gas defrost if you are initiating a gas defrost from a central controller. Not something we tend to do in the UK now because gas defrost has died to death.
Definitely. And over temperature alarm for everything set it realistically, customers are gonna have a spec if you are doing a customer that hasn't got a spec. You're an engineer, you, how high that fixture's gonna realistically go during normal operation. And it's gonna depend what it is. If it's the, let's take a popular one.
(00:43):
So set it. Tighter. Smaller room's gonna lose temperature faster. If it's a case, the manufacturer's gonna have a spec for it. Set it in line with the spec. Change that spec at your peril because most customers will have you strung up for changing the spec and they lose products. So stick to customer spec where it exists.
So that gives you a much more stabilized response for the shelf temperature. Yeah. So that goes into probe six, usually on an IBM controller, and it's got its own temperature ranges. Okay.
So like. Get some manufacturers who say, , you defrost defrost hours, or you defrost interval six hours, let's say. Right? Carell's a good example. Carell says defrost interval. If you set it for six, it'll be six hours between defrosts. If you send defrost number for six, you'll get six defrost a day.
Yeah, and you've got all your fan settings and light settings and all that good stuff. Lights and defrost can be set on a timer in around one. If I went into the right one, it would help. In the front end, you've got a timer option. You can, you can ask the front end to do all your timers for you. Yeah.
now exactly that you could do. Exactly. Yeah, exactly. It. It. So yeah, if you wanna do it on the cabinet, if it's one cabinet, lighting times are right there. So when you are coming to set up your transducer bit, like we, we talked about previously, all your transducer parameters are right here.
From the bottom of the transducer to the top. So if it's a minus one to 65, your span is 66. Offset is, do I need to adjust it? The bottom end below zero. So if it's a minus one transducer, that will be minus one. Yeah. MOP, as we talked about, custom settings for refrigerants and probe sets. Yeah. If you've got really long cables, again, we've talked about before, if you've got really skinny cable and really long runs, that cable's gonna carry a resistance.
I know the evaporator probe is on the inlet to the coil. I know it's gonna get the coldest straight away. I know the air off probe probably gonna be the next one to get cold, and depending on where the defrost probe is, maybe the defrost probe just between the two supply air, I'm gonna expect to be the last one to get cold.
You can do it with the bottom left button on the controller, hold it down and it will go into defrost. This one won't because it's too warm, but you can do it on a live one. I know in reality, everyone's gonna push the contactor in to do it, but you do that at your peril. And I can tell you right now, the last job I commissioned at my old place, I did exactly that.
Yeah. You, another beautiful thing about the way the RDM does it, you don't have to configure this graph. It will log all the data points. Right. But it's just giving me control temp there. I can tell it's select trace and I can stack myself, my air, my air off, whatever it's gonna show me all those different traces.
It's logged all the data for me. It's sets all the probes up. I've plugged, , a 10, 12-year-old controller straight into it and it's come online without me doing anything. So it is a massive labor saver for you guys on site. Compared to some of the, the torturous ways to set stuff up, I'm not setting points up or anything like that.
It's the suction. Am I doing something wrong with my case setup? Have I got the soup heat setting too small and we're into unstable? Have I got the response time too fast and the valve's hunting? Have I got a poor airflow over the coil and a little tiny change in the valve is killing the suction temperature.
Is something blowing into my fixture? If it's a warehouse type retailer and it's got a big old train unit blowing around, it's gonna be blowing in the case. I can pretty much guarantee that 'cause they always are. If you've got cold aisle heating in a supermarket, that can blow into cabinets. We've got a lot more doors coming in on fixtures now it's a lot rarer to see that, but I'm checking that when it's on defrost, I'm checking my defrost termination probes and met the temperature 'cause it, if it's terminated on time, I'm asking myself, why is it terminated on time?
learned, right? No, no. Yeah, of course. It, well, do not pull it down as fast can. It's when it's, when the job's gone wrong and you start pulling it down two days before handover, isn't it? It's, it's always done. It's,
He's, he left it not working. Even if you left it working and it failed 23 hours, 59 minutes later or a week later, you, it's still Kev who did it. And it's Kevin's fault that it's not working. So
Yeah, yeah. It. And if you come back 24 hours later and you check it and you go, do what? I was right about that? I need to look at it, then you've done the right thing. If you just assume that it was working when you left and it breaks down, your name's gonna be mud and it's, you don't want that.
Kevin, I love this. We, we could have talked for another three hours just on this topic here. There's so much notes. Like I, I scribbled down tons and tons of notes. Again, I really appreciate you taking the time and I really I really like the last thing that you talked about, about your brand and your reputation.
And then if you're listening to this, go back and rewatch even the first seven or eight minutes where Kevin went through his steps, step by step procedure on what to do. That's what, that's the approach you take on all controllers, on all startup cases, because it is the wiring, it is a trace where the location testing them, and I know I talked to lots of you out there like, Trevor, I got 200 cases, or I got a hundred cases, or I got even 30 cases.
Because once you open it up to the system, your problems multiply very quickly if it's not right. So take the time. If something doesn't look right, address it before you let gas into it, because that is when panic sets in and you are chasing around and you're hurting things that were already running before you got there.
look, know what's right when you're doing jobs, have the confidence. It's the last message, is the right one that you just said. Have the confidence if something's not right to say it's not right and not let it happen. Take take charge of your own destiny in that regard.
Welcome to the Refrigeration Mentor Podcast. Hope you're doing well. We're gonna be doing a live demo today with my good friend Kevin. He is been on the show many, many times diving into controllers. He is the CO2 expert. And yeah, as always, love that you're sharing comment on this stuff. Just if you're getting some value from it, please share it with someone.
(00:01):
All I had was some quite old ones in the garage. And I reached out and they put me up with a new one. So thank you very much for that.
Yes. And as we said, a lot of the things that we'll do here, even though they. Geared for IBM in this case, we'll apply across the board with different controllers and yeah, the setup on the front end will be different, but the steps you take to do that case or do that cold store are pretty much the same for all different systems.
They'll put the defrost probe and your coil, inlet and coil outlet probes in the end of the coil. Usually. Now if you've got a really good electrician, they might fit the probes for you, but I'm not a very trusting guy with probes. I'm gonna go and have a look and I'm gonna see where they are and I'm gonna make sure they're secure, fixed on the pipes.
If it's a small job, you won't. If it's cabinets that you're doing, am I gonna take every case of partner check where every probe is? Probably not because I would love to, but in reality, if I've got 20 cases to commission, that's a hundred probes to check potentially, and I'm not gonna have time. What I'm gonna do is if I don't dunno that brand of case, I'm gonna take one, two bits and I'm gonna check where the probes are.
When your case fitters come along and bolted all cabinets together, they're gonna remove the fan plate. And what's gonna happen is the fan wire's gonna be stuck in the back of the blaze. And when you switch that on, you're gonna get DA and you are gonna think, oh no, it's chewing through the wire, so I'm gonna do, , it's true, right?
So if it's RDM, there's several different ways we might be going online. RDM likes IP as it's main networking. It will also do RS 4 85 and you can connect, if it's on ip, you can go different ways. You can go through a hub. The RDM will supply you and you can have multiple fixtures in there, in which case some of the addressing is done for you.
If you short those two connections together, you're gonna break in the cable somewhere near the panel, you are losing the lot. IP is more resilient to that. You, yeah, you can have, start, have one cable from the where panel is to all your fixtures, but you gotta be extremely unlucky. And if you lose everything, , it's that cable.
And you just because the cable looks the same, it doesn't mean it's talking the same language. So, on an RDM controller, like this one, the socket on the side is a category five socket. Regardless of what type of network it is, this actual one plus out two, three. Two. So don't be fooled by the type of cable it is.
And that was the way we used to do it. Everything on RDM before they put direct IP into the controllers. So you have options, but just because it's the right type of cable doesn't mean it's ip. You've gotta check what type of network it is and you, you've gotta know what you're plugging it into.
A couple of things to point out on here where it says NC on the mains, NC means not connected, not normally closed. Don't put anything in there on the relays. It's exactly as you would expect normally closed. Normally open and common. Okay? They're all vault three relays. Down there. So you've gotta put a supply onto them.
It's this is their RD m's front end. Fantastic piece of kit. Makes everything nice and simple to use. I've had a lot of devices logged on here in the past. My new RDM controller, which I've just powered up, is that one. So all I've done for that is I've gone into the controller network menu and there's an option called id and it's a three digit number and I've just picked any three digit number to put in there.
Mm-hmm. So, because I'm, 'cause I'm going ip, I have my module and I have my three dials to set an address right there, right? So it's hundreds, tens of units. I'm just gonna set number one to three and we'll see if that logs the sun. I'll plug it in. If it doesn't go bang, it'll be a sweet miracle when I can let the power up and we'll we'll go for it.
Now, there's a menu on the RVM controller that called type. You've got types one to six on most of their controllers, and that gives you presets, right? So that will give you whether you are on a case, let's say. Or a cold store, it will give you certain default options. Like do I want fans on in defrost? Do I want a door switch?
Like a month. It's never 43 degrees in the uk it's 43 Fahrenheit maybe. Yeah, yeah. So I'm immediately thinking when I see that, am I on the right range of probe? Because RDM supports multitude of different probe types. Read the manual is what I would advise on that. And just check your probe types.
There we go. So, so number 300 there is the controller that I disconnected. So that's a big, pretty good demonstration with RDM of how robust it is with old controllers that my data manager is about 18 months old. The controller I've just connected is well over 10 years old, and all I've done is put an address in it, connected it on, and it's appeared.
So I'm happy with that. They're all saying virtually the same, which also is good news to me because if I've got three, say in 25 and one saying 35, I'm saying they're all in a room together. Why is one much higher than the other? I also notice from that I've got a suction line probe fault, right? And the controllers flash in P prb four on the front.
Brilliant probe falls out very easily. So the next thing I'm doing is I'm going chasing that fault and I'm gonna put that wire back in. So I've got all my probes reading at that point, I'm happy they're all saying the right thing. I'm not gonna do it now. I'll probably get electrocuted from my dodgy setup.
It's gonna be quite a tinny little sound, and I'm happy then that my valve's working. One thing to note with RDM if is where, if it's a mechanical valve with a solenoid, it is wired fail safe. So on the back of your controller, it's wired to normally closed as are the fans, right? So check your relay one, your relay two wired normally closed.
Which is which is what we all wanna do. I'm also gonna be looking at my transducer if I've got a transducer fitted. Now what I'm gonna bear in mind is if I'm on vacuum and it's not a minus one, two something pressure, , let's say a thousand PSI, if I'm that 200 bar, whatever. If I'm in a vacuum and it's not rated to minus one, I may be showing a fault.
So I'm gonna be checking to see if there's a reading on that. I'm not gonna worry too much if it tells me when I come to set it up that there's a fault with the evaporating temperature because RDM knows that you ain't gonna operate this below the triple point, and I wouldn't be worried about the reliability of that reading until I've got pressure in it.
You get then to what you're getting on the rack or what you're getting on your gauge, depending on where you got connected, and go from there. Yeah, it, it's it's one of those where you can easily start chasing a faulty transducer only to find that you just need to put some pressure in it and it'll be fine.
(00:22):
Your case manufacturer is gonna tell you what you want on that RDM percentages hub. Your number is the percentage of the error on, right. So if you set that to a hundred percent that is reading a hundred percent of the air on IE exactly what the error on process says. You said it's a zero, it's reading a hundred percent error off.
Cold stores usually. A hundred percent air on because you wanna read the warm part, right? You wanna read the air going back outta the room. That the only time I would deviate from that on a cold store is if you've got, let's say, a dual discharge cooler in a teeny room and you've got a really bad situation with air bouncing around the room.
Of the controller to what it's controlling against. So that one will be how the thermostat operates and that one be what shows on the screen. Right.
Air on is the air is er, air return air. Just wanted to clarify that. Right? So we get the return air, air on, that's the air going onto the coil air off.
It will, it will eventually end up at the air on and you'll get those two values reading differently. There'll be 31 Celsius now and tweet. Yeah. So when it eventually updates the, so there we go. Right. It's got a grip of itself now. So you see it's reading all of the air on value. Yeah. Whereas before it was reading an average of the two.
Right. So, and this, this is how we check the probes as well. All I would do in a cold store, I would have somebody holding that probe and I would watch what the value did and I would then check, because I know it's the error on probe now because I've seen the, the number go up. And it's worth saying if you, and good point you make about the, the probe settings and what people call them.
We can do that with any input, any output, any parameter, and any alarm. So if we want to call things, classic example is cold stores. So RVM calls all its alarms case. Even if I change that to, to a cold room, it'll still say case over temperature when it alarms. But I can do an alias change through this panel and I can change that to say, cold store high temperature.
And then we'll, we'll know what that fixture is. It will, it'll eventually update. That's my fault. Okay. There you go. It's updated now and I'm going a little fast for it. Okay. So in our parameters that we're gonna do, other than that alarm weight, so you might not want it. To alarm on air on or air off?
You then got your EV settings, 'cause it's an EV controller. You can set your super heat reference in there. Six is a good starting place as we know. If you need to turn it colder, you need to turn it warmer, you can do it from there. Response on and response off is how fast the controller responds to the super heat changing.
And what, yeah. And what we know we all know very well is that. Everyone loves to see PI and D there, but actually quite comparatively, few people know what PI and D actually do.
It wants to keep trickling some refrigerant through it, so you've got a chance of rectifying itself. If you'll use the transfuser and it sees a super heat fault, you'd set that to zero, not a problem. And it'll then wait for its its problem time and then it will try and start the valve up again. And that's useful if you've got a brief issue with the rack that you've solved, and then the case will get away by itself.
If it gets below that limit, it's gonna go into problem. Yeah. And depending on how you shut set that, it's either gonna shut the valve or it's gonna keep the valve a low level. The problem when you are only controlling on probes, if you are not using a transducer to get your inlet temperature, your evaporating temperature, if you shut the valve completely, you may, if let's say the coil's absolutely clear and you've just had a rack issue, when you start it up, it may struggle to get away because you've not got any temperature sense to the inlet.
I think it's important too, read any manual, but for an example start opening percent. That's gonna be different if you're on a chiller versus a long run cold storage. 'cause if you, you have that at 75% open start opening and you're only two feet away from the compressor, you're gonna be in some trouble.
All the start opening is therefore is to let you stabilize the super heat. Yeah, it comes, it comes from a time when we didn't use transducers. Really, in all honesty, it's just about settling the super heat down. But one thing I will say, just as I say about reading the manual, I know nobody enjoys read reading.
let's talk about the, like maybe the six or seven. 'cause there is a lot that you're showing there, but what are like six or seven on like, MOP is a big one for sure. You,
After the MOP delay, it will shut the valve by whatever percentage you've set that diviv value to, which is a parameter away at the top. So they are value. So if I set MOP to, let's, let's say it's CO2. Let's say I set the MOP to 40 bar Yeah. 600 PSI, whatever it is, it will, if it hits that and the time elapses, whatever percentage the valves at, it's gonna half it you, if the valves at 50%, it's gonna set it's 25%.
You can ask the fans to stop when it stops cooling. You can ask, ask the fans to stop on defrost. This is one to read in the manual. The app, so you can set fans that, for example, fans temp mode in there to temp, and then if you get to that temperature, it'll switch the fans off. And this is stock protection to a degree.
Because if you've switched the fans off, you can't sense the temperature accurately. So it will bring the fans on every often to do that. You can tell it what prob five does in this case, it's defrost. You can set it to be monitoring as well. You can tell it where the lights are. This is where you tell it, how am I sensing my evaporating temperature?
Switch resistors, that's a, the useful one. So you can tell the controller by putting a resistor across some of the probes to put itself into fan only put itself into lights only. You can tell it to do a defrost. You can tell to lots of things with the resistor across the controller. Again, explain to the manual, but if you want that function, you need to turn it on and then.
You can set two different temperatures and that will switch between two. Or you can tell it, if I see that input, I'm gonna go into defrost. That's quite useful for things like gas defrost if you are initiating a gas defrost from a central controller. Not something we tend to do in the UK now because gas defrost has died to death.
Definitely. And over temperature alarm for everything set it realistically, customers are gonna have a spec if you are doing a customer that hasn't got a spec. You're an engineer, you, how high that fixture's gonna realistically go during normal operation. And it's gonna depend what it is. If it's the, let's take a popular one.
(00:43):
So set it. Tighter. Smaller room's gonna lose temperature faster. If it's a case, the manufacturer's gonna have a spec for it. Set it in line with the spec. Change that spec at your peril because most customers will have you strung up for changing the spec and they lose products. So stick to customer spec where it exists.
So that gives you a much more stabilized response for the shelf temperature. Yeah. So that goes into probe six, usually on an IBM controller, and it's got its own temperature ranges. Okay.
So like. Get some manufacturers who say, , you defrost defrost hours, or you defrost interval six hours, let's say. Right? Carell's a good example. Carell says defrost interval. If you set it for six, it'll be six hours between defrosts. If you send defrost number for six, you'll get six defrost a day.
Yeah, and you've got all your fan settings and light settings and all that good stuff. Lights and defrost can be set on a timer in around one. If I went into the right one, it would help. In the front end, you've got a timer option. You can, you can ask the front end to do all your timers for you. Yeah.
now exactly that you could do. Exactly. Yeah, exactly. It. It. So yeah, if you wanna do it on the cabinet, if it's one cabinet, lighting times are right there. So when you are coming to set up your transducer bit, like we, we talked about previously, all your transducer parameters are right here.
From the bottom of the transducer to the top. So if it's a minus one to 65, your span is 66. Offset is, do I need to adjust it? The bottom end below zero. So if it's a minus one transducer, that will be minus one. Yeah. MOP, as we talked about, custom settings for refrigerants and probe sets. Yeah. If you've got really long cables, again, we've talked about before, if you've got really skinny cable and really long runs, that cable's gonna carry a resistance.
I know the evaporator probe is on the inlet to the coil. I know it's gonna get the coldest straight away. I know the air off probe probably gonna be the next one to get cold, and depending on where the defrost probe is, maybe the defrost probe just between the two supply air, I'm gonna expect to be the last one to get cold.
You can do it with the bottom left button on the controller, hold it down and it will go into defrost. This one won't because it's too warm, but you can do it on a live one. I know in reality, everyone's gonna push the contactor in to do it, but you do that at your peril. And I can tell you right now, the last job I commissioned at my old place, I did exactly that.
Yeah. You, another beautiful thing about the way the RDM does it, you don't have to configure this graph. It will log all the data points. Right. But it's just giving me control temp there. I can tell it's select trace and I can stack myself, my air, my air off, whatever it's gonna show me all those different traces.
It's logged all the data for me. It's sets all the probes up. I've plugged, , a 10, 12-year-old controller straight into it and it's come online without me doing anything. So it is a massive labor saver for you guys on site. Compared to some of the, the torturous ways to set stuff up, I'm not setting points up or anything like that.
It's the suction. Am I doing something wrong with my case setup? Have I got the soup heat setting too small and we're into unstable? Have I got the response time too fast and the valve's hunting? Have I got a poor airflow over the coil and a little tiny change in the valve is killing the suction temperature.
Is something blowing into my fixture? If it's a warehouse type retailer and it's got a big old train unit blowing around, it's gonna be blowing in the case. I can pretty much guarantee that 'cause they always are. If you've got cold aisle heating in a supermarket, that can blow into cabinets. We've got a lot more doors coming in on fixtures now it's a lot rarer to see that, but I'm checking that when it's on defrost, I'm checking my defrost termination probes and met the temperature 'cause it, if it's terminated on time, I'm asking myself, why is it terminated on time?
learned, right? No, no. Yeah, of course. It, well, do not pull it down as fast can. It's when it's, when the job's gone wrong and you start pulling it down two days before handover, isn't it? It's, it's always done. It's,
He's, he left it not working. Even if you left it working and it failed 23 hours, 59 minutes later or a week later, you, it's still Kev who did it. And it's Kevin's fault that it's not working. So
Yeah, yeah. It. And if you come back 24 hours later and you check it and you go, do what? I was right about that? I need to look at it, then you've done the right thing. If you just assume that it was working when you left and it breaks down, your name's gonna be mud and it's, you don't want that.
Kevin, I love this. We, we could have talked for another three hours just on this topic here. There's so much notes. Like I, I scribbled down tons and tons of notes. Again, I really appreciate you taking the time and I really I really like the last thing that you talked about, about your brand and your reputation.
And then if you're listening to this, go back and rewatch even the first seven or eight minutes where Kevin went through his steps, step by step procedure on what to do. That's what, that's the approach you take on all controllers, on all startup cases, because it is the wiring, it is a trace where the location testing them, and I know I talked to lots of you out there like, Trevor, I got 200 cases, or I got a hundred cases, or I got even 30 cases.
Because once you open it up to the system, your problems multiply very quickly if it's not right. So take the time. If something doesn't look right, address it before you let gas into it, because that is when panic sets in and you are chasing around and you're hurting things that were already running before you got there.
look, know what's right when you're doing jobs, have the confidence. It's the last message, is the right one that you just said. Have the confidence if something's not right to say it's not right and not let it happen. Take take charge of your own destiny in that regard.
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