Episode 330. Oil Issues in Refrigeration Systems

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In this conversation, we’re going over oil troubleshooting in refrigeration systems. This episode covers common issues like dirty systems, plugged filters, and improper system designs that can lead to oil failures. We’ll also talk about pressure differentials, proper installation practices, efficiency tests and mechanical issues like short cycling and blow-by. Understanding how to identify oil issues on service calls will help refrigeration technicians troubleshoot more efficiently and better serve your customers.

In this episode, we cover:

-Understanding oil issues in refrigeration systems

-Dirty systems 

-Maintenance tips

-Pressure differentials

-Troubleshooting oil failures

-Compressor efficiency tests

-System design and installation issues

-CO2 systems and overheating problems

Helpful Links & Resources:

Episode 53. Understanding Oil Issues and Building your Technical Database

Episode 56. Two Stage Transcritical Dorin Compressors

Episode 247. Oil Management with Patrick Gregory

Episode Transcript

Speaker (00:00):
What's up everyone? Welcome back to the Refrigeration Mentor Podcast once again, super happy that you're here. Let's dive into some more troubleshooting, diving into oil troubleshooting. So this is one of the things that I know in a lot of my programs, one of the. Things besides controls and electrical, it's oil issues that are really sometimes hard to solve.

(00:01):
One of the things is though, there is always a reason for a problem or an issue that could be a manufacturing issue, that could be an installer issue, that could be a service issue, that could be a maintenance issue, that could be a customer issue. There is so many different things that could these issues.
Make sure you clean all three. At least at minimum. 'cause maybe you don't have an extra oil filter there to replace. You want to, after you clean one, we know that system is dirty. You should be recommending oil maintenance for that. You should be writing this up. So this is a follow up, right? So maybe it's, , you gotta check the pressure differential across the oil separator.
I see this a a lot of the time. That you get an oil failure. So it's a tro, it's a delta pie, it's a pen, or it's a Danfo oil failure control. And they're tripped off. The compressor's tripped off, and then the technician comes in and they reset it, and then it doesn't trip off again. While they're there, they sit for, I did this.
Well, if you change two or three, it's not a bad batch. It's the, the chances of it being a bad batch coming from the, the manufacturers, it happens, don't get me wrong, but it's very slim. , Very slim. And it is something that you need to take a look at. 'cause I've had people say, oh, well it's a bad batch of Delta Delta PIs or Delta P twos.
There are positive pressure. So your, your oil pressure. Versus your crank pressure, that'll give you your net pressure. If you get net pressure and it's tripping off on your oil failure control, that's probably dirty, or you don't have a gasket on there, there's something going on with that sensor. It could be the, the module itself, but chances are it's very slim that it's the module, especially if we change it two times.
The oil faial control. Another thing could be blow by that compressor. This is why compressor efficiency tests are so, so important. You have to do efficiency tests, and a lot of people are, what's that? , Is that just closing the suction line and, and checking how deep of a vacuum it pulls and how no, that's, you are only checking your discharge valves at that point.
If you can you can get that. What is the oil level in the compressor. If you have a sight glass on it, these are some of the checks that you need. Then you need to plot that. You need to plot that on that, that electrical curve chart. So this is how you, you check that because the blow by could be causing your oil issues.
You can actually watch the oil level drop really quickly, and if you have this happen, you have to service the compressor. And what do you, I mean by that? You have to pull the heads off properly, isolate the compressor, take out all the bolts in zep two, knock it with a a rubber mallet or a hammer or something because it could be on there real good so you don't blow it off of your face.
That's just the oil bouncing around in there from the velocity inside there and the movement inside there that is not really a flood back. Flood back is when you get a lot of foam and it's white and then all of this. Sudden it's huge. And then all of a sudden you see the oil levels start to drop sometimes really quick, sometimes slowly depending on a, and then within minutes, depending on how bad it is, it could wash all that out, all that oil outta that compressor and that could trip off your oil pressure control and cause an oil failure trip.
That's when that other, tX valve or EV starts to flood back, that circuit starts to flood back and wash out the oil of that specific compressor. And these are some of the things that, that cause oil. Other things, , is in the, the design or the install. Maybe someone didn't properly put the slope in the ceiling.
I've seen technicians and install people well, oh, it's usually a engine three, not an engine five. And they go with the engine three and they run into major issues. Okay. Because in the, with new designs of equipment, new efficiency, BTU ratings have changed and velocities depending on these new system, maybe it used to be with that refrigerant and engine three.
That is the only way you could tell if you want to change the size of a pipe. You can't just say, oh, well I've seen this before and it should be that, and I've seen this. Multiple times I hear stories in my, my courses in academies. Oh yeah. The, the lead tech. And I didn't, I couldn't say anything. I'm, I'm just the apprentice.
It could be that you have the OCV is not properly sized. It could be the wrong set set up. So for example, if you have compound compressor, say Carlisle zero six ccs. So these are compound compressors. They have multiple pressures in them. So if you took the suction pressure, you would never get oil into them.
They would go back, they would add oil, it would trip off the oil failure controllers. Again, there was nothing staying in the re reservoir or receiver oil reservoir or receiver. It just always been pushed out to the system and they couldn't figure it out. So he came out. And he started looking around the system with them and they added a pile of oil to the system and they, he went there and then he started to watch the system run, and then he started to see some of the grass, and then he started to see a trend of overheat.
And you'll see in all the manufacturers, they're gonna say, you can have just a small percentage mix of oils. They don't want any mixture, but if you're doing a retrofit, maybe a, you'll have some mixture in there. So it's a very small percentage, 10 or 5%, depending on the manufacturer and sometimes even lower.
And these are just a few that I I'm talking to you about because there could be other things. That, that cause oil issue. It could be the design, maybe a solenoid in the, in the line that maybe you gotta plug solenoid or a dirty soil or a filter. A lot of the new CO2 ones have like little torpedo filters in them, or little filters.
Low load could be an issue. So, 'cause I've seen this as well. End users designing like. Three times of what they need. Well, we're gonna expand. We're gonna expand next year. And I know this is tough on you as a technician because there's like, I got no load. How do I even start this up? Like it runs for three minutes and it all shuts off and then all of a sudden it warms up and then it runs for three minutes.
Another thing I see on a lot of CO2 ones or well, is piercing valves. Has the piercing valves for the flow been set up properly? Have they even been open? They may not have been. You may not even know have seen it. , You may not even know, or ever seen a piercing valve in a oil line, but it could be that.
Why is it still. Keeping a good eye on on that and what happens when I take it off? What does happen at that point? Understanding all of this. Who's gonna make you a better technician in the field? Be more valuable to your company. Be more valuable to your customer. Make more money in the long run. Reduce your stress and that's what all the my programs are about.
So if you can take one or two things away from this episode is that please share that with other people because this is how we all get better. Super excited. And if you're ever interested in getting into some of the refrigeration mentor programs, always head to refrigeration mentor.com. Check them out there, go into the YouTube channel.