Tales from the trenches, stories forged in the fires of experience.
For more resources, make sure to visit escogroup.org.
Alright everyone, thank you for joining us. We're hanging out with the Eugene Silberstein.
Eugene, hello.
Thanks Cliff, it's really good.
So one of the things we want to talk about in Tales from the Trenches is maybe it's not always your fault.
Maybe we need to step back and re-examine an entire situation to be able to look for faults that may be other than our own.
So Eugene, you've got some fantastic stories to share in this topic.
Well, having been in the industry for 43 years, if we don't have at least a few Tales from the Trenches, I think we're going to definitely remiss in what we're doing.
Exactly.
But yeah, you know, when we're talking about things that might not be your fault, a few situations and scenarios just pop into my head as vivid memories of this industry.
I mean, like I said, having been in the industry for over 40 years, you can imagine how many service calls we've been on, how many projects, how many installations.
And to have a few, like literally three pop into your head as these are the top three.
And there was one scenario and it drove us crazy for literally years and years and years.
And we had a rooftop package unit and it was a 10-ton rooftop and it had two 5-ton circuits, two 5-ton compressors, completely different circuits.
And the system was installed and had two stages.
Obviously stage one would run one circuit and stage two, the second circuit would come in.
And we could never get the system to operate on single stage.
And this was many, many years ago. I was still younger in my career.
And what would happen was when the thermostat was calling for first stage cooling, the first stage compressor would turn on and the system would pump down and turn off on low pressure.
So a restriction maybe.
Yeah. And it wouldn't start. So now we're like, well, you know, what's going on with this? Why are we cutting off on low pressure?
But when the space temperature rose and second stage cooling kicked in, then both stages ran and cooled perfectly.
Oh, really? So not a restriction.
Yeah. So if it was cooling perfectly, then there would definitely be no restriction in the line. So check out why we're cutting off on low pressure.
Well, it works on second stage cooling, but not first stage. It has to be an electrical problem.
Right. Pumped down a solenoid or something.
So the senior tech on the job went through all the wiring and re-ran all thermostat wiring, replaced the thermostat, grasping at straws, doing a lot of things.
And this literally went on for quite some time. And the unit never ran on single stage.
And again, when you think about a system not running on single stage and going off on a low pressure control, again, people are automatically thinking down one specific path.
Yeah, very my optic.
Yeah, very my optic view. And what did we do wrong? This was the word on the street. Like, what did we at the company do wrong? Did we wire something wrong?
Did we put in a thermostat that wasn't compatible? We didn't do any evacuation, piping, charging.
Because it ran fine once it was up on second. Yeah.
And then everything was perfect once we got to second stage. And it was kind of the assumption that, well, you know what?
Maybe this is how this system is going to operate because we've done everything we could do.
No one can find it. Yeah. Until the stage one compressor failed. So the stage one compressor failed and had to be replaced.
So our team goes out to recover refrigerant from the first stage loop. And each of those circuits held six or seven pounds refrigerant.
So let's say seven pounds. And the technician is recovering refrigerant from that circuit and pulls 14 pounds of refrigerant.
Each circuit is supposed to hold about seven pounds. And yet we successfully pulled 14 pounds of refrigerant out of that circuit. And then the light bulb went on.
So we actually had members of the team go out and trace out the refrigerant. Refrigerant plug. Yeah. Trace out the refrigerant circuit on the system.
And there were two pipes that were crisscrossed at the factory. Wait a minute.
So the reason the unit was pumping down on first stage was because the second stage compressor wasn't running.
But that second stage compressor was in the circuit. So picture refrigerant making a figure eight through two complete loops.
So instead of going through one compressor, one condenser, one metering device, one evaporator back to that compressor, we were actually going from compressor one to condenser one to metering device to to evaporator two.
And the refrigerant was actually making a figure eight.
And like I said, this was going on for years. People on the team were going and running new thermostat wire going through the factory wiring.
But nobody thought because it was a control issue. Everybody thought it was a control issue because when we hit stage two, everything worked fine.
So it was a really, really interesting learning experience. Kind of an eye opener for where does the refrigerant flow.
And like you said, it's not always your fault. But I think sometimes we just need to take a step back and realize that things that happen are not always, I wouldn't say our fault.
You know what? Had we started checking line temps, we would have realized that hindsight is always 20-20 Clifton because, you know, say, oh, if we would have done this, we would have seen that right away.
But it took the compressor failure and the refrigerant recovery to actually open our eyes and say, well, you know what?
There's definitely something going on with that. You know what? Being that we're talking about piping issues at the factory.
You know, I was involved with a project. I wasn't the installer. I wasn't the service person, but I was a willing observer.
I was actually going to be the occupant of the space that this system was to service. And it was an air-cooled chiller.
And I was a faculty member at this institution. So I'm not facility, so I can't touch anything. So, you know, union issues.
And so I was there to teach. I wasn't there to mess with equipment.
And we had an air-cooled chiller installed for the building. And brand new building, brand new chiller got installed.
And this was back in 2009. And the chiller was being installed with R407C.
So they did a whole...
Yeah, warranty replacement, retrofit.
And it actually went in R407C brand new.
Oh, really?
Yeah. Yeah. So we made that decision with R407C from the start, but did an analysis and determined we're going to go R407C.
So anyway, so the chiller gets installed and starting up. And the startup technician could not get the chiller to function correctly.
And right away, his company was like, oh, well, did you charge the system correctly?
Yeah.
Well, we don't think so. We need you to recover all the refrigerant from the system.
Wait and charge it again. And now we're going to send over other technicians to make certain that it's charged correctly.
And they could not get the system to function.
They actually had a chemical analysis done of the refrigerant because the company was saying that the technician caused the R407C to fractionate.
And something was happening with the refrigerant. And they did this three times. They analyzed the refrigerant.
The refrigerant was fine. They recovered. They evacuated. They recharged. They recovered, evacuated, recharged and could not get the system to function.
Now, here I am.
So it could get it to capacity, could get it to run or?
Yeah. It would not cool. What happened is the operating pressures were so high, the head pressure was running excessively high.
And the subcooling and the condenser was excessively low. And the low side pressures were high as a result.
And superheating the evaporators was fine. And it just did not sit right in my brain because high head pressure is an indication of a system overcharge.
Right. And low subcooling is an indication of a system under charge. Right.
And when you get that disconnect, just like if you get low suction pressure, that's an indication of an under charge and low evaporator superheat, that's an indication of an overcharge.
That's an indication there's an airflow problem. Airflow.
So we had high head pressure indicating an overcharge and low subcooling indicating an under charge, which in my brain points toward an airflow problem, not necessarily a refrigerant problem.
Okay, sure.
So I wasn't really supposed to, but I had my students visually check through the condenser coil to see if there was a blockage.
Check the motors, check the rotation of the motors, check the blades, check the pitch. Everything was correct.
We measured airflow, we have airflow through the condenser coil.
And so high head pressure, low subcooling pointing toward an airflow problem, but we have airflow.
So what is the other possibility? Well, the other possibility is that the condenser coil is not sized properly.
Sure.
So, well, the condenser coil is the condenser coil. It's installed on this air-cooled chiller.
Right. It should be matched with the airflow.
So, yeah. So I actually had my students, again, we weren't supposed to do this, but we did, trace out the refrigerant flow path through the condenser coils.
And they marked both ends of the coils and it was a W configured coil.
And what the students found was that three out of every four of the tubes in the condenser went nowhere. They circled back onto themselves.
Relooped?
Yeah. It made a loop that didn't go anywhere. So three out of four tubes.
Yeah. So the condenser was basically 75% smaller.
Yeah, absolutely.
Than what the capacity of this, what the system was sized for.
Right.
So now the challenge was how do I tell people what the problem is without telling them? Because I wasn't supposed to do anything.
I wasn't here, but there's a problem here.
Yeah. So it was really, really neat. And ultimately the condenser coils were changed out and this just worked fine.
So those two really popped into my mind about the mis-piping.
But what's really, really funny, Clifton, is being that we're talking about things that might not necessarily be our fault.
Yeah.
I was on a job. We were installing a commercial system at a drugstore in Manhattan.
And the equipment was on a roof setback. And we were doing the install and we were actually piping down the chase.
So we're actually in harnesses and we're being lowered into the chase.
We're doing the refrigerant piping. And it was a remote condensing unit. So we're running the suction line and the liquid line.
And it got to the point where we finished piping, we leak checked, and everything was fine. And we went to evacuate the system.
Sure.
And we were near the end of the day and the refrigerant line runs were pretty lengthy.
And at the end of the day, we put the system on a vacuum pump and we left.
You left one overnight? Sure.
Yeah. This is back in 1989, 1990. So we were going way back. And we let the vacuum pump run overnight.
We got in in the morning to check our vacuum and we were confident because we pressurized.
Sure.
We held a pressure test.
Yeah. And our gauges were reading about 10 inches of mercury.
Okay.
We didn't use micron gauges back in 1980.
So we're like, wow, hold it. We're not holding a vacuum. So we were able to pressurize the system and we held.
And we call the office and we tell our service manager, listen, the system's not pulling down into a vacuum. We only have 10 inches.
Right.
Well, you have to have a leak. You got to look for the leak.
Somewhere. Yeah.
So we checked everything we could find. And he's like, listen, the store is open. They're still getting the store ready to open.
Right. They're getting the shelves. They're stocking the shelves. People are there all day getting the store ready.
And we spent the full day checking all the solder connections, the solder joints.
And couldn't find anything. We're tightening up the connections. We're just tightening.
Searching for anything.
Yeah.
And at the end of the day, we said, all right, well, we'll see what we got. And once again, we turned the vacuum pump on.
We left for the night, came back in the next morning and we're at 10 inches of mercury.
Really?
And Clifton, this literally went on for almost a week. We were looking for the leak.
Where's this leak? It's got to be here.
Yeah. We actually had to go back down into the chase and cut the suction line insulation off the lines.
And we're literally leak checking. We're going down in harnesses. We're being lowered down.
It was a major, major work.
And it was getting really, really frustrating. We could not pull this. We were holding a pressure.
And we just could not get the system to pull into a vacuum.
So we got, I mean, we changed vacuum pumps. We've got brand new vacuum pumps, changed the oil.
I mean, we did whatever we could do. And we're in the mechanical equipment room and we're beating our heads against the wall, almost literally.
Yeah.
Because we were told, you cannot leave this job until you find the leak. And it was about eight o'clock at night.
We were still working and we were in the mechanical equipment room and then somebody from the drugstore walks in and they said, oh, you guys are still here.
I'm like, yeah, we're here. You know, we're still working. Take care of something.
And they said, oh, well, we're shutting down. And they go to the circuit breaker panel and they start shutting all the circuit breakers off.
And all of a sudden they hit a breaker and my vacuum pump turns off.
So what happened was they were leaving at night, turning everything off.
And then they were coming back at 6, 37 o'clock in the morning before you get there.
And we got there at eight o'clock in the morning. Our vacuum pump is still running, still running.
Right. It's been on all night. It was running when I left and it's running when I got here.
And we looked at each other and we just threw our hands up in the air.
And so, it's so moral of the story is now if you are, if you intend to leave a vacuum pump on overnight, at least mark a circuit breaker.
Do not turn me off.
It was actually really, really crazy. But you know, it's so funny. Like I said, 43 years in this industry.
And those three instances when you said, oh, we want to record some tales from the trenches.
And immediately these three just popped into my head. And it's like, had we done things just a little bit different?
Had we looked at things just a little bit different? Different perspective.
Yeah. You know, we don't always have control over things. But these kind of things only happen one time.
You know, once something like that happens with a vacuum pump.
I mean, we will blame it the vacuum pump. We will blame it the vacuum pump oil.
It was actually really crazy. And then it was just that light bulb when that gentleman came in and started turning the breakers off.
It was actually pretty interesting.
That is. I love that. That's a perfect example of why we do tales from the trenches.
After the first couple of these, I started thinking I should have actually named this Do As I Say, Not As I Did.
Eugene Silberstein, we are so grateful for your giving back to the industry and everything that you represent and do for us.
Thank you so much, Eugene.
My pleasure.