Tales from the Trenches, stories forged in the fires of experience.
Alright, thank you everyone. We are joining Patrick Murphy in a follow-up conversation from one of our Teaching the Unteachable sessions.
This one with Tales from the Trenches is going to be about deep searching for refrigerant leaks.
Welcome. Glad to have you here, Patrick.
Yes, glad to be here.
Alright, let's dive a little deeper into this one because I love this store and this is a great one to pass on.
A lot of good educational opportunities.
You know, leak detection methods have improved so much over the years, but they still require some time to go through a system and totally check it.
Yeah.
Now, if you have a brand new system that you've just installed and you've got a leak, you're going to be tearing your hair out.
And I will literally tell you that's exactly the circumstance we ran into.
We had a brand new system that was installed in a supermarket. It ran three meat cases.
The machine room was downstairs in a basement and we charged the whole system up.
The system was running fine for two or three days and then it started to leak.
Now, you naturally start to check everything. We're in the cases, we're in the machine room, we've gone over everything.
We're shutting things down and building pressure up to 400 PSI because that's what these evaporators would handle.
And we cannot find the leak.
And what you have to do is you have to start to think, okay, where are the possibilities of the leaks?
Right. Map it out a little bit. Visually map out the entire installation.
Those overall possibilities, well, where else could there be a leak?
Well, to get to supermarket cases in a machine room that many years ago, you ran pipe in a trench.
That's exactly right. People don't realize how many trenches are in the floors of grocery stores.
And the trench was then covered over with a wooden floor because at that time they put wooden floors in meat rooms.
In this particular instance, we could not find a leak in the cases or in the machine room.
And one of the guys said, I'm going to find this leak. And he attached his leak detector to a 50 foot length of quarter inch copper tubing.
Oh, there's an interesting idea. To be able to get down into the floor?
No, actually, the trench to the meat room was right off the machine room.
Okay.
And literally, we ran that tubing in and at about 25 to 30 feet in, we picked up a leak.
Oh, be darn.
So, yeah, up we go. The carpenters are still on the job site.
We make them tear the floor up. The sleepers for the floor are 16 inches apart.
And wasn't it funny that the nail that was shot into the suction from a healthy gun was dead center between the two of them?
Wow.
It was just one of those leaks that it was almost impossible to find.
Sure, absolutely. And where you had to get a little creative in how you utilize your tool.
I mean, our leak detector is a tool. We know that there's a leak somewhere further than the tool can reach.
How do we extend the reach of our tool?
Exactly. Exactly. And, you know, those are not the only times that a technician in the field is going to have to use his imagination to try to find the leak.
Oh, yeah, absolutely not.
Or to find out anything that's going wrong on the system.
I mean, we've literally had circumstances where high head pressure, same hundred ton air conditioning system is cutting out every other day.
OK. So commercial split system.
No, it's a big commercial split system.
Yeah, OK.
And it's in a big box store.
Yep.
And you're checking the high pressure control. You're checking this. You're checking that.
You've thought of everything. And the big box store manager is not happy that you've been back three or four times.
Sure. Whatever is not right.
And you clean the condensers at the beginning of the cooling season only because they haven't been cleaned in four or five years.
What? We never run into that, do we?
Yep. And you walk up on the roof and you're looking at the condensers and you can literally stand inside these condensers.
Yeah, absolutely.
But you're looking at them from the outside and they look clean.
There's nothing to matter with them.
And you turn around and behind you, there's an earth moving device.
Clearing some land.
And dust is wasting across the top of the unit.
Yeah.
And they're converting an old drive in movie theater into a housing development.
OK. Now I'm following along.
And the dust has just finally coated the condensers.
Real, real fine dust.
Super fine dust.
OK, now I'm starting to paint the picture. I can, you know, I can see this condenser, right?
You're doing a good job explaining this one.
Yeah. Those condensers wound up being cleaned three times that summer.
I gotcha.
Which was there was nothing we could do about it, but they had to be cleaned.
And, you know, we would tell that to the store manager and he would go, you just keep.
You just cleaned it.
My system is clean, he said, because I don't want to lose any more chocolate.
Because every time the condensers would go down, the building would get too warm and start melting chocolate.
The chocolate would start to melt.
So it was more important to keep the systems in operation.
Right. So you know, you know, this is going to be called the chocolate story for now on.
You can call it chocolate story.
I love it. It's so true.
I mean, we think about that may not have been covered in large amounts of dirt,
but just that fine dust is enough to pack inside of the condenser coil.
Yes. Yes.
I mean, and again, you have to use all of your senses when you're out there in the field.
And actually when you're in the classroom to know exactly what's going on when you're doing all the different things.
Plus trying to manage the fact that you've got, you know, 10 to 15 people in the classroom who are working with somewhat dangerous equipment at times.
Oh, yeah, absolutely.
So that's, you know, it's just all of these little things add up when you're driving to whatever job site you're going to start to think ahead of time.
Okay. What's been going on with this new piece of equipment or old piece of equipment?
I mean, if you had a rainstorm go through and the design of the supermarket was such that they they put the transformer in a low spot
and the drain for the entire parking lot was in that low spot.
And it was one of those torrential summer rains that you get.
And next thing you know, the transformer is covered in mortar and shorts out.
Oh, wow. Okay. And I've seen a lot of transformer pits before.
So, you know, a very common installation. Yes.
And you wind up with an instance where you have to keep that frozen food for making sure there's a lot of product in there.
Yeah, absolutely. What do you do?
Hopefully you have a dry ice place near you and you can make sure you put somebody in a vehicle loaded with dry ice who's smart enough to leave the windows open.
Sure. And hope that the police don't stop them because the vehicle will be sublimating
as you drive. I can only imagine sitting here thinking about what that would actually look like.
Yeah. Well, I can tell you I can tell you exactly what it looks like, especially pull up and you're you're wearing a ski hat ski jacket in the middle summer.
And hair is hanging out of the back of your head because you're about 19 years old and it looks at you and goes, where are you going?
Hold on a minute. You better explain yourself, son.
You had to explain myself that all this dry ice is going in the freezers and it sure saved the day.
We were able to save that. That's that is so interesting because a lot of people don't realize, especially, you know, for our younger techs out here that are getting into commercial refrigeration.
This is an eye opener. I tell this to all my friends when we start talking about refrigeration at grocery stores.
We've not sized a generator to run the refrigeration systems in quite a few decades.
You know, the capacity of a generator that would be needed to run the entire mechanical system is quite mind boggling.
So all of our emergency generators at our grocery stores, those are for lighting and emergency operations.
They're not for refrigeration. So when we lose electrical, yeah, now we go into panic and emergency mode.
You talk of another circumstance in a supermarket where we just finished a repair on the air conditioning in the supermarket.
Yep. As we walked out the front door, I mean, we just replaced, you know, a hundred ton motor.
You walk out the front door and you hear an explosion.
And you're like, no, this can't be. You go racing back in. You're in the machine room and you don't smell anything.
And you're looking around. You start testing things with your working with a flashlight on your shoulder and you're sure whatever you can find.
And you look at the store manager, you say, you know, I can't figure it out. And you walk out the back door and you see a fuse on a telephone pole has blown.
Oh, wow. You call the electric company. They come in and they say, oh, yeah, we've got to check the transformer.
Hopefully it's not bad. And they open the transformer up and you're standing there and you look down and you know, oh, that rat must have been in there for a long time.
Look how dried out he is. The guy from the electric company looks at you says, no, that's your problem.
He was jumping between L1 and L2. The tail was on L1. Oh, my God.
He was on L2 and that's the 10,000 volt before transfers down to 480. Oh, my goodness.
So you had a nice freeze dried rat. Right. On the primary side of the transformer. On the primary side of the transformer.
And those are the kinds of things you've got to look all over the place. You can find everything to make sure that you you don't have an instance where, you know, something outside of your control has taken over and gotten to the system.
Yeah, absolutely. Yes. Very, very good. I love that story.
I mean, because it's so true of the scenarios that you will encounter while out in the field.
And it's about getting that mental preparation, painting that picture before we get there. That's the reason we're doing these in podcast form is to paint that picture of what things you have to encounter when you're on the job site or before you even get to that job site.
Yes. On the way to the job site, you just start to think of, OK, why am I going to it? Is it a service call where there could be an issue?
Customer is saying, I don't have any air conditioning. You have a multitude of things that could cause that. Yeah. Classic one is the air conditioning unit is put in a spot where it's it's close to a hedge.
And you get to the job site and you start the unit up and you can hear the unit run, but the condenser fans not running. Sure. Right.
You open the unit up and the condenser fan motor is very hot. But you look at the shaft at a condenser fan motor and it's got this lovely roping around the shaft.
And you're like, what is this? And you trace it back and you find out it's a vine that grew into the condenser. Sure. Got inside the condenser area, wrapped itself around the shaft.
Yeah. The shaft spun around and seized the motor. Once you cut everything loose and the motor cooled down, everything was fine.
Which brings up another point to think about. You know, how often in the field do we have to expedite that cooling process of a condenser fan motor?
You know, one of the tricks of the trade is to go grab a garden hose and help cool down a condenser fan motor or a compressor that is overheated.
Yeah. There's so many opportunities that we have while we're assessing our scenario to help expedite things to get things back up and running again.
You talk about keeping things running. We're all talking about the cold weather heat pumps today. Sure. Hot topic.
The first heat pump I worked on was 150 tons. Oh, wow. It was very advanced. It was in a manufacturing plant.
It would generate cold water and hot water at the same time. And it fed three 20,000 gallon storage tanks. Oh, really?
And it had a storage system and it was really sophisticated for its time. Yeah. We're going back to the 60s. No kidding. Yes.
And the issue that came up was on a real hot day. Once the storage was at full capacity on the tanks on the water tanks and you couldn't store any more hot water in there. Right.
You had to get rid of the heat somewhere. OK, sure. Unfortunately, when they designed the system, it was 150 ton heat pump, but they only put 100 ton condenser in. Oh, OK.
And when you say grab a garden hose, the eventual solution on a hot summer day was we wrapped a green flat garden hose around the top of the condenser, the air cooled condenser, and made it an evap condenser.
We literally little municipal water supply and sprinkler. We literally tied it on to a reverse acting head pressure switch. Yep. And when the pressure got high enough, we turned on the garden on the water.
I love it. Yes. Is it what you really want to do in today's market? No, absolutely not. You will. You will hopefully have an engineering circumstance that has not put 100 tons with 150 tons. But yeah, exactly. At that time, that was that was a temporary solution.
According to the engineering standards they had come up with at that time. Sure. Absolutely. Because they were anticipating some of that load shedding being on the water supply at all time. Definitely. Yeah, absolutely.
So a lot of times it's a matter of evaluating our equipment and looking for some of the circumstances. I used to encounter the same thing quite a bit in remodels, especially grocery store remodels, where an engineer would change the capacity of the cases and anticipate that a condenser having a certain capacity to it.
But may have had some modifications over time. And then you end up with systems that don't have proper condensing capacity for your amount of cases.
And a lot of times I won't show up until the middle of summer or the middle of winter. So a lot of times when we have to go reevaluate our total capacity on our indoor equipment versus our outdoor equipment.
Yes, you have to look at the equipment and make sure that it's going to match up. You also have to be inventive during remodels.
Because during remodels, sometimes you're moving a set of cases down six foot to add the new case in or eight foot to the new case. Now with today's cases, I don't believe you'll be moving them as much because there's so much glass doors.
Right. But literally we've had cases that had to be moved eight foot down to put a new case in and you had to keep all the product in it.
Sure. And so we put a hydraulic jack against it and jacked it down. But before we did that, we ran the tubing and then the tubing just flattened out as we jacked it down nice and slow.
Oh, okay. So you have to be creative. Our jobs are not just, you know, this is the way we do it.
You have to think outside the box on a lot of circumstances for all the different occasions you can run into.
Yeah, absolutely. Patrick Murphy, thank you once again for joining the show. We're grateful to have you here with us.
Great. Thank you.