This was a mystery, I was trying to find out why the fuse had blown and it's not always an easy solution.
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00:00 SPONSOR CARD
00:43 YOU CAN'T BUY THIS QUALITY ANYMORE
01:26 VISUAL INSPECTION
02:40 CONTACTOR INSPECTION
04:51 LOW VOLTAGE
08:02 DISCONNECT INSPECTION
08:30 TIMECLOCK INSPECTION
09:40 RE-WIRE EXPLANATION
10:20 COMPRESSOR WINDING TEST
15:57 CONTACTOR TEAR DOWN
18:18 CLOSING WORDS

This video is brought to you by sportlin quality, integrity and tradition. I'm here today on a follow-up, because i had another service technician come out here yesterday on the emergency service, call for the walking cooler not working, and when he arrived. He found that the number two fuse in the disconnect switch was blown, but he couldn't find a reason why the fuse would flow, so he reset it and it's been running for almost 24 hours, but it's saturday now and i just don't feel comfortable. I just kind of wanted to get my eyes on it.

We may or may not find a problem, but i'm just going to open this guy up and see what we can figure out. This is older equipment. We were looking at the history it's from 1997.. Certainly can't get stuff that'll last as long anymore.

This looks like it's an original compressor. Still, 97., it's a pretty simple system. It's a walk-in cooler with a pump-down solenoid downstairs. Everything downstairs is on its own individual circuit breaker, so we had a three-phase breaker three-phase fuse.

So the number two fuse and that disconnect switch was blown so the problem more than likely, is going to be up here. Um, it's an independent evaporator. Basically so we're going to open this guy up. I don't see anything crazy jumping out at me.

Yet the box is down to temperature right now. So that's a good sign. I do not have camera footage, but when i walked into the box it was at 37 degrees, but it was in defrost, okay and then i walked up here and it was running. But honestly, judging just from my experience, the compressor didn't sound like it had a load on it, so i'm going to get some service gauges on this.

As i was taking this cover off. I noticed that when i dropped this, it turned off. So we could have a pressure control, that's starting to fail or starting to drift, but this is just a preliminary idea. Temperature wise i mean it, doesn't tell you a whole lot when it's not running, but i was curious if we had a restricted, suction filter.

Again, i'm just doing a visual right now, so i am gon na go, get some probes um! That contactor certainly looks older, but nothing is jumping out at me in here. It doesn't look horrible, we'll open this guy up. Get this guy taken off, get a look inside the back of there. I mean everything on this is like almost original.

This is crazy. You know they really don't make stuff like this anymore, open it up in here i pulled the cover off. The contactor certainly does not look good in there. That contactor looks horrible.

So that's not a good sign um, but we're not gon na just stop there we're gon na keep going i'd, be suspect of that disconnect switch interesting. Oh no, that was just a the refrigerant. Sometimes can leak by or boil out of the oil or the compressor and turn the system on for a split second, so um. We definitely need to get some service gauges on this, so we can understand exactly what's going on down here.

So, of course, this is how this works. It's raining on me right now, um go figure, it's not hard. Yet so we're gon na keep working on this, but the pressure control doesn't look to be malfunctioning. It looks like it's set to cut in about 68 psi and it has a 35 degree differential um.
So it's shutting off, i think about where it should be um. I definitely don't like that contactor. So we're going to wait for it to cycle again and then just kind of oper or watch the system operate i'll, give it a few more minutes. It's not raining too hard yet, but i don't necessarily want to be stuck up here if it's working um, but that contact is the contactor is definitely suspect.

Pulled off. The cover for in here definitely looks like maybe some wires rubbing in that back corner, but i don't see any arcs or anything i mean everything on this looks pretty darn decent. Besides it being old, um, probably a smart idea to pull the defrost clock, bend it over. Look at the back terminals, make sure there's nothing funky going on there, don't see any melting from loose wires or anything.

I think we are getting ready to turn on right. Now i think that the system uh is calling so we're just waiting for the. I thought i heard a solenoid valve open, so we're going to give it a second i'm going to change the contactor, but i want to see it turn on and see. If we can test for a voltage drop across that contactor, i did not measure any voltage drop across the contactor, but we went ahead and changed it anyways because it looked really bad.

We are running slightly low on the scale that does happen from time to time. In this area, 200 volts, that's that's a little bit low 200 volts. So i can certainly see with voltage like that and a load like that, compressor that a pitted contactor could you know you're gon na you're gon na start to see some higher amps for sure everything's. Looking good, i mean refrigerant, wise, we're running a clear sight: glass.

I'd like to see that head pressure, a little bit higher, let's uh, come on over here and grab discharge is hot. Liquid drain is cool, liquid line is warm, so the head pressure control valve certainly is bypassing and it's it's running through. That's fine, hmm! What else is going on here? We're gon na test for some temperature drops across the dryer real, quick just to make sure all right. We've got a 88 degree liquid line coming out of the head pressure.

Control valve we've got a 67 degree liquid drain. So it's shutting off the flow coming out of the condenser and we have a 172 degree discharge line so we're certainly bypassing on our head pressure control valve all right. Now we're going to test the temperature drop across our dryer. We could do pressure too, but temperature is easy enough, so 85 degree coming out move it over to here.

It's like 86 degree going in. So it's about a 2 degree. Temperature drop, i'm it's probably okay, it's slightly an issue, maybe um, i'm just gon na grab. This guy, this is coming out of the suction dryer 54 degrees.
Now, let's look at going into the suction dryer 47 degrees, so we're gaining heat, but that's to be expected because you're coming from insulated to non-insulated, let's as we get closer look at if i move it closer, the temperature drops so yeah, it's re losing heat, but We do have a pressure port, so we'll go ahead and check pressures across that guy, real, quick, we're at 37 psi on the outlet of the suction dryer. So we need to get a pressure reading right here. It's like we have a slight refrigerant leak right there. I don't know if that comes across it's about a that's interesting, a 2 psi gain.

I'm intrigued by that. I think. Oh no, there we are yeah it's about a 1 psi, but it's gained, so i think we might be pumping down or something or dropping up there. We go we're at 37.

Now so no it's it's really! No pressure drop across the suction dryer. I'm not seeing any issues there. I came down to the disconnect switch. We had just put new fuses in here yesterday.

I checked for a voltage drop across the disconnect and i don't see any um. It doesn't look like there's any problems in here. The knives seem to be making good contact, don't see an issue there, huh yeah, i'm not seeing anything else going on with this guy open up the back of the contactor. I mean it doesn't look great, but it doesn't look horrible.

The points aren't really aren't the greatest, but they're, not really everything seems to be working. One thing i didn't check is: does this have the right time and it does not? Oh, but this clock's not even being used now this clock's, not even in the picture, because we have a ke2, 10 plus defrost controller downstairs, so clock really could be taken out of the picture if we want to so i'm gutting the eliminating the stuff that doesn't Need to be here and in the meantime, while i'm doing that, i'm checking the system for potential places so that defrost clock was still wired into the system, but it wasn't being used so just yanked it out and then yanking the wiring. What i'm finding is is the wires are too short because they were, they were running to specific places. So i just pulled two new wires to the pressure control.

Really quick. It's not taking me long at all and i'll wire, those into the contactor and then we'll uh investigate this crankcase heater, we'll probably have to extend these and get them wired into the contactor, but other than that. Everything else is looking pretty good. So far, all right, i cleaned up the wiring made it easier.

It's pretty self-explanatory. Now, let's see power comes off of line. One goes through the pressure control comes out of that goes into one side of the contactor coil line, two jumps directly to the other side of the contactor coil, so the pressure control is the thing that is responsible for solely opening and closing that contactor simple. As that three-phase power coming in the top uh three-phase load exiting the bottom condenser fan motor on these bottom two wires right here exiting the bottom everything's good, defrost clocks, eliminated um, crankcase heaters wired back in i've got the uh compressor plug opened up.
I didn't see any issues with the electrical in there, we're owing it out 1.6 amps uh, i'm sorry, 1.6 ohms, 1.6 ohms, 1.6 ohms to all three legs. So we're going to go ahead and do a mega test on it too. Real quick, all right, um run a test at 500 volts, it's a 208 volt compressor greater than 550 mega ohms. So don't see any problems there everything's looking good um, i'm not seeing anything.

That's telling me this thing should trip. You can see that uh should blow a fuse or anything um we put in a new condenser fan motor. I did it, you know, there's not a whole lot. You can do about this because you don't have the oem stuff anymore, so we made sure that the wiring is secured with zip ties.

So it's never going to rub out everything's, nice and secure. There's no potential for shorts on the condenser fan motor will verify that. It's running at the right current, but i don't see any issues with that other than that. I don't see any other things going on up in here.

Everything seems fine. One thing i will say is that disconnect switch is kind of redundant because you have a breaker right there and then you have a breaker downstairs, i guess maybe per code. You have to have it externally, because in order to get to that breaker, you have to open this unit up, i'm not a huge fan of using fuses on a three-phase system, because in our situation one fuse blue and potentially single phase the system. Now, in our situation, the fuse that blew actually was the control circuit, so it shut down the contactor.

You know so um, i'm not seeing anything else going on with this guy yeah. I don't know what else to tell them. The uh condenser fan motor is allowed to run 2.9 amps we're running under current on that and the compressor i'll have to get on the clamp on there and then we'll pull up poco mobile and see what we're allowed to run on that too. The compressor is running right at about 6.7 amps and uh.

Let's uh do some research on cochlear mobile app and see what this guy's allowed to run. I'm in the copla mobile app right now really simple gives you all the information for the compressor. You can go home basically, this is it right here i searched it, find the right one. High temp, 233 phase.

You've got all this information. Mechanical gives you information on that. I mean tons of stuff, so we go in here we go to electrical, we go to summary. Rla is 12 amps.

I mean i'm not seeing any issues winding resistance. 1.3. We're good on that. You know everything looks good, so we're uh yeah we're good.
As far as the compressor goes right now, i've done pretty much everything in my power to try to find why this thing would have flown a fuse, and i don't see any issues um i inspected the disconnect switch. Certainly it's older, but i don't see anything wrong with it. I don't test any voltage drop across it before i even ran the mega. I went while the system was running and jiggled every conduit to see.

If maybe there was a short in the conduits, no nothing. I certainly could start magging every wire, but i don't really see the need in that motor is running. Fine current's, good electrical connections inside that box are good. I ended up just because the wires were too short.

I ended up replacing the wires in the pressure control, but there was no issue with those i inspected them when i pulled them out. Um compressor, ohms out proper. According to copeland mobile uh, you know disconnect switch. I tightened all the electrical connections went ahead and replaced the contactor because it didn't look good that certainly could have been a problem.

Okay, we are running a little bit lower on the spectrum as far as the voltage goes, but we're certainly within tolerance. Okay um. It does happen here where we're running right at 200, volts in the summer time will probably hit a little bit lower they'll get like 198, which you know you don't like that, but still it's with intolerance. Now uh.

You know we have issues like this in certain areas, certain cities - you know they just have poor electrical distribution. Now um. Yes, i know, there's a million people, that's going to say, call the utility get the voltage raised buck boost transformers all that stuff. You know.

I leave that up to the customer, okay, you have to draw a line somewhere and i'm going to let an electrician deal with that kind of stuff. I'm going to stay in my lane. You know if, if it was just one individual feed, then we'd get an electrician involved. You know, but this is the entire building.

This building is always operated like this too. So at this point i have done everything that i can think of at this moment. You know you know to make sure that everything is good all right. This is certainly older equipment.

This is an older coil um, it's kind of hard for you guys to see, but this is a reverse airflow, so it sucks in through there and blows out that way. So it is a little dirty on the evaporator coil. That has nothing to do with our fuses blowing. At this point right now, the box is down to temperature, like i told you guys, there's a ke2, therm, temp plus defrost controller right here.

Everything else seems: okay, so we're gon na tell them to keep an eye on it and uh yeah. I can't really figure anything else out that might be going on, so we'll just tell them to watch it all right. So i went ahead and pulled the contactor out. I didn't disassemble it on site, but i took it back to my shop, i'm sitting in my office right now and i'm just pulling it apart just to get a visual.
So we don't know exactly what caused the fuse to blow. Okay at this point, we're gon na have to use our education and make an educated guess. Okay, we look at everything right. We try to look at the big picture.

We try to solve the problem and not just the symptom. The symptom was the fuse was blown, but why? Okay, so we're going through everything, there's always intermittent problems that don't always present themselves at the time of the diagnosis. Okay, but you know we, we just look at everything and this contactor, i'm not a huge fan of while it was still operating and technically when i tested it at that moment it did not have a voltage drop across the contactor. You can clearly see that the points do not have a very good.

You know they don't look very good. Basically, okay. Now these points right here are the contact points. Okay, they go inside this contactor.

You know i disassembled it. These aren't really field repairable, um, this guy, you know it's kind of a pain to get apart, but once you start taking them apart, you kind of get used to them. But these points right here are the point of contact boom, makes contact like that. Okay, so it just goes boom right and it has to make a good connection there right and we clearly have deterioration of the points right there, carbon buildup, you know all kinds of crazy stuff.

Now this contactor is an older contactor, it's not original um. I don't necessarily see a date, sometimes there's a date code on them. I don't know if any of this is the actual date code, but this is an older contactor. I'd say this probably about 10 years old, judging by the looks of it, but we changed it out of pure precaution, but at the same time this could have been our problem.

We clearly were running on the lower end of the voltage scale right at about 200 volts that tends to make everything run a little bit warmer. So you know we just have to do our best, and at this point i made an educated guess. Of course, the customer was part of the conversation they understand what's going on here and i feel comfortable, i can sleep at night, knowing that i pretty much did everything within my power within reason. The way that i look at it as long as i do everything within reason in my power to try to solve the customer's issues, you know i can sleep at night.

I i really can, and even if i have to make an educated guess, i'm gon na use, you know my skills and use my knowledge and say: okay, you know what all this stuff is going on: the contactor it while it wasn't testing bad. It didn't. Certainly, look good and it's a pretty good possibility that that was part of the issue: contactors pull in and out multiple times and every once in a while. If you've ever witnessed it, they can make a bad connection, and it only needs to happen once for it to.
You know run lower than normal voltage to maybe one of the phases of the compressor, and then it causes a high current situation potentially and causes a fuse to blow. It's always possible that maybe there's something going on in the disconnect switch. I mean there's so many different variables, there's so many things it could be an intermittent problem. The compressor could be locking up every once in a blue moon.

I mean there's so many different things going on, but we kind of attack looking at the low-hanging fruit, just kind of using everything right and, of course, keeping the customer in the loop, letting them know. Hey, there's always a possibility. This could happen. This could happen.

Let's change this contactor, it's going to become a problem sooner than later and uh. You know i feel comfortable with that, so i i just try to do my best really. Okay, it's amazing all the support from all of you uh. You know the the views, the interaction, the comments um.

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That's that's a really cool accomplished feeling for me, it's really neat, so i really appreciate you all um i have. I cannot announce anything yet but got some cool stuff we're working on right now for the future uh. Realistically, it's probably even too soon to tease it because it probably won't happen for another six months to a year, but there's some other cool things coming into the picture. Uh some new educational resources and different things so should be fun um.

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Okay.

5 thoughts on “Why did the fuse blow on the walk in cooler ?”
  1. Avataaar/Circle Created with python_avatars Ryan Baik says:

    13mins ago? Arent you sleep? πŸ™‚ Service area Kanata??

  2. Avataaar/Circle Created with python_avatars neilvester victor says:

    One mistake it's time clock you call it contactor πŸ˜† big picture diagnosis

  3. Avataaar/Circle Created with python_avatars LazyTV says:

    πŸ₯Ά

  4. Avataaar/Circle Created with python_avatars Gabes Reef Tampa says:

    πŸ‘πŸΎ

  5. Avataaar/Circle Created with python_avatars Ahmed Alyami says:

    πŸ˜€

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