THE WALK IN FREEZER KEEPS BLOWING THE FUSES
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- Опубликовано: 8 сен 2024
- This was kind of a tricky one as I never found that one problem that said this is it....
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One of the biggest problems with intermittent short circuits is that when they arc they often blow themselves clear and can last for ages between incidents. For me the prime suspect would be the heaters. Not just the evaporator defrost heaters, but the drain and compressor heaters too. Or it might just be that there's a damaged wire or an unexpected cable joint somewhere in the wiring that has been bodged.
The coldroom disconnect full of ice is a possible suspect if it's been causing tracking inside the switch itself. The more waterproof you make stuff like that, the more likely they are to hold it in.
But a very tricky diagnosis, especially when older components do tend to show a bit of insulation breakdown over time. Are the fuses rated for the possibility that the compressor runs on after the heaters have been powered for a defrost, giving a brief higher current?
The water in conduit is also suspicious._
I still don't understand why they don't use RCD. Short circuit and leakage to ground is quite different.
@@andreavico6198 RCDs (GFCIs) would be a disaster on refrigeration equipment where water and electricity are side by side.
@@BigClive In my country RCD is mandatory and of course we use fridge.
@@andreavico6198 Easy, USA. Besides that, depending on the building/electrical code for the area, usage of such a device could/would be prohibited as per regulations. Even if such a device could be used, it's as Clive said, would be hell on high power refrigeration equipment like many businesses here in the States use. It's easier to bear in mind that the US has much different electrical codes/standards compared to the rest of the world.
I'd vote that switch as most likely being the cause of some issues, the water level was between an active and the ground and rust would have made the water fairly conductive. Maybe it tracked once it was almost dry
Same here. That's a solid "bad" in my book.
Holy cow, Chris actually had full 208VAC at his incoming for once.
Best comment😂
I'm in Canada and our voltages are either right on the money, or above it.
@@Jason-wc3fh Depends on the city. Some remote towns out here in Alaska have better voltage than Anchorage.
Great video, we had this issue several times. Safety tip. Use a wooden pencil instead of your finger to check for shorted wires, you won't get buzzed near as often
@Sean Embry thanks for the the tip too
one of the things you can do when you suspect a small electric leak to ground is to put your current clamp around all the live wires. If the insulation is in working order then the current measured that way will be 0.
But a small live to earth leakage current shouldn't be blowing the fuses.
Boss move.
In your area given low supply voltage during high demand times I would put a line voltage monitor or a current monitor on that system. You did your part and checked everything extremely thoroughly.
If they have a voltage interruption for less than a second, you can get a full load amp spike when the power returns
Hey next time you are there check that CCH. I’ve seen quiet a few times CCH shorted to ground but at that particular moment you walk up that cch isn’t making contact with the compressor casing. But as the compressor runs the cch will vibrate on the compressor and short itself again. Now that I know that I’ll find this issue 5 times a year.
Intermittent issues, the band of every technician regardless of system...hopefully they'll simply change it out and be done with it! Thanks Chris!
Two things ate my lunch on one of these calls. First was the disconnect switch filling with water like this one, and a disconnect that had gotten so hot, so many times that it was losing its conductivity. Who knew a disconnect could go bad this way. I do now.
22:22 They are nichrome wires and will change resistance as they heat up and have resistance and can't be tested with insulation tester. All you can do it go to ground and one of the heater leads, not across the heater itself. Also on weatherproof boxes always have a weep hole in the bottom. I have seen more outdoor boxes full of water because overtime rain will get in, so does condensation. Keep up the good work sir.
Something i noticed. When you were using the FLIR on the evap.....looks like the door gasket is leaking. You can see infiltration of heat around the door. You did a very thorough inspection of the system and thats all anyone can ask for. Another great video Chris
**** For Megger readings....you should have a value in megaohms an equivalent of what the voltage is. Ex.....208v= 208,000 ohms(.208 megaohms) ( 1megaohm per 1,000v ) at the lowest ( industry standard is 1 megaohm minimum). With that said, the one heater reading 87 megaohms and the rest much higher. I'd say that heater is on its way out, but has some life left in it. Before you even got to that part of the video i was telling myself that it was the defrost heaters and thats where my money is on.....Baldor will say that anything less than 100 megaohms, the motor should be replaced. I go down to 50 megaohms and i call the motor out for replacement or repairs. On a VFD controlled system...if the megaohms is 40 or less the srive will not allown it to operate and will lock it out on a safety interlock.
The door frame is heated.
It was great work putting a new gasket for the switch. That will keep the water in for sure.
I will discuss this on my Livestream this evening 10/24/22 @ 5:PM (pacific) over on RUclips , come check it out ruclips.net/video/bHwhvet7lrM/видео.html
Some industries refer to those rogue strands of wire sticking out of terminations as a "George Michael" (Careless whiskers.)
as in Arrested Development? lol
How about no auxiliary on that contactor
Could it be short cycling at times on a defrost pump down causing the compressor and heaters to run at once
So not only do I have the identical evaporator in my walk in but I also had the exact same issue. I found my issues in the terminal landing board as a wire connector got so weak that it was just about 80 percent cracked. I touched it very gently and it broke. Replaced all connectors and my prob was solved. I’d absolutely check out that Stat near the TXV though as those stats have landing screws vertically and any water run down could easily cause that short. Great video
The biggest issue I have with those types of fuses blowing is the clips that hold the fuses gets weak or bent more open and doesn't hold the fuse tight enough causing it to blow from heat.. however that should have shown up with the heat camera
I would say the switch for sure. Water could still be inside that switch and frozen and sometimes when it thaws/refreezes it could be intermittently shorting to ground
These vids are gold
Waterproof mini breakers will tell you a whole lot. I installed a handful on my last system install. I went way overboard though. Gave it its own sub panel: condenser, evap, heating system, condensate pump, controls with lighting is how i have everything seperated for the breaker. I also added 3amp breakers between the controls and coutner parts and added a contactor for the heaters. If anything goes out, controls stay on for data longing and lights stay on. Panel will let you know it its evap or condenser side, fans will blow the 3 amp mini breaker or the fan speed mini breaker. If a heater shorts, the breaker will tell you. My goal was to preserve as much of the equipment as possible in the even of a failer, easy troubleshooting, and keeping the system on in the event of a non critical failure such as a heater. Its on a farm and they have thousands of pounds of grass fed, free-range meat in there so i wanted to do everything I can to mitigate the chance of losses. I went with the KE2 system also to reduce wear on the defrost system.
Great video!.....I have the same issue at hand right now.....
I disagree that minor issues only. A switch enclosure and conduit full of ice/water can energize the box and stray current so dangerous....The restaurant at least proactive with new equipment. Great call and big picture exam!
I will discuss this on my Livestream this evening 10/24/22 @ 5:PM (pacific) over on RUclips , come check it out ruclips.net/video/bHwhvet7lrM/видео.html
Thank you for the videos. They are an excellent source for those who are considering buying equipment for a commercial kitchen. Your thought process when diagnosing things is a lot like mine.
In my experience it's usually the evaporator solenoid or fan harness wires rubbing out on the fan motor mounts or other wires
I recognize that paragon digital defrost clock! I think you replaced that very same one(or at the very least, one of the same model) about 2 or 3 years ago, I thought the digital LCD defrost clock was a very neat idea when I saw it back then, since there's no moving parts to jam up with sand or dust.
As standard practice do your tech document which fuse (left, right, center) was blown? If they changed different fuses it just goes back to beat down equipment. If they both changed the same fuse, that helps diagnose which leg is the issue.
That switch box is a good candidate. Just had that happen on a WIC.
Good job Chris. I learn something every time I watch.
Good job Chris.
Great Video. Thank you for sharing
Adding ferrules to stranded wire will prevent all those mashed up ends, plus the fly away strands are much easier to see when you crimp on the ferrule if you miss one rather than up under the contactor where you need an inspection mirror.
We would use ring or fork connectors over here.
Switch that sometimes gets water up to the terminals look like a good candidate for an intermitent problem to me.
Not sure why that wiring and the switch wasnt insulation tested, condensation and high corrosion visible most likely source in the whole video.
About that flooded switch - I haven't seen any comments regarding the locknut still on the liquid tight connector between the gasket and the box. Certainly not helping to keep water out.
Remember that an induction motor will draw its rated Watts no matter what. If the voltage on the leg sags the current draw will go up. If the voltage dropped to 100 volts, the current will double.
Looking at the big picture here… I see like 500 things that could potentially pop that fuse intermittently, but that waterlogged switch and it’s seal-tight conduit are what’s jumping out at me. But of course, due to it being an intermittent issue… of course the problem doesn’t occur while you’re there. 🤣
Master electrician working in industrial environment for 25 years. When I run into intermittent fuse failures and can’t identify the source I do a couple things. Determine if it’s the same fuse failing. In a three phase system feeding single phase equipment, is it one of the fuses that feeds the single phase stuff? Can you isolate that leg to specifics equipment? If I’m stumped, Ill sometimes carefully cut the fuse open to see if it’s a short circuit or overload resulted in the open circuit. Short circuits will result in a catastrophic failure of the element. Depending on type of fuse and how it’s constructed, overloads can melt out soldered connections, melt the element, etc. there was no current measurements displayed on camera ( or I missed it) while in defrost cycle. Would have been good to get comparative amp reading on all the heater strips and combined load. Given that the current draw of the fan motors and compressor looked good and with the amount of moisture in that unit and the previously wet switch, I would assume a short circuit resulted in the open fuse. If that switch shuts down the unit and the employees are working inside the freezer at a breading station, assume they are flipping that switch to shut down the fans to keep from freezing their nards off. A switch that has been wet and has corrosion in it can short internally and open a fuse.
an IR test is an electrical pressure test of the insulation in an electrical installation. Low IR readings indicate leakage current, which can cause equipment frames to become live at mains potential if proper earthing is not provided.
I didn’t see you using the other tool in your bag ? Your nose ! You should always inspect with eyes /ears /nose . You can smell a burnt smell that is fine tuned after a while. Great video as always ! Love this channel.
Can you do a video, of a anatomy on the refrigeration parts of these condensers?. I get so confused with all the valves ports, there's so many and it gets confusing
good job as always those electric shorts can be a real bear to find stay safe
If you have phase and or voltage issues phase lose relays may be a good idea to automatically shut down equipment if any phase goes below a certain voltage, maybe add a notification device so they know to be extra conscious of open doors when the equipment is not running, possibly also a mechanical latching contactor as a tell tale that would get latched by the phase loss relay and only manually reset so you know when a power issue has happened when you next come out, that alone if you can't auto shutoff would at least tell you equipment vs power issue so you know if you can just replace the fuse or need to do something more.
Man I really need to get a thermal imager. The level of troubleshooting is insane
now finding best bang for the buck.
Flir one pro is what I use
@@HVACRVIDEOS very nice.
That Fluke can be connected to your phone with Bluetooth, all of a sudden you got a multimeter with a wireless display. Actually really handy.
Something not mentioned is the possibility of bad power. Perhaps dropping a phase. It would also be nice to know which of the three fuses went each time. It might eliminate some of the single phase stuff.
there should be a special Y for the electrical lines going into the cooler to prevent moisture going in,putting seal tight on top of switch makes it worse,thanks for sharing.need drain hole on switch box.ohming to ground will probably read drain heater resistance.i would replace it.
maybe they're having brown-outs or losing a phase and the current is going very high or even high current back-feeding when a phase is lost.
not sure about there, but in commercial buildings the utility companies will often connect a data logging meter to monitor power conditions at the location. you may check into that if there is not other explanation.
Nice meter!
I didn’t hear it mentioned…..was it the same fuse that blew both times recently? Would it matter? Just curious.
I didn’t hear either but my guess is yes it was the same line. Being able to tell which leg is tripping would narrow things down a bit you could see which things are wired to that line
@@shifter8207 thanks. I know nada about HVAC systems and only dabble in electrical wiring at home. The only fuses I deal with are in cars. LOL
@@barmanvarn all good you’re welcome
If you have dual element fuses you can dissect them to see if it was an overload or short circuit failure.
I vote that the switch is the core cause of the issues.
That current draw makes sense if one motor is across A+B and the other is A+C.
I think a big part of this problem is the switch and associated wiring in the coolroom,once a switch gets water in it, it's never the same.
So nobody else saw the spark inside the compressor contact @ 4:05, would not that explain the increased current on one of the phases AND the intermittent nature of the problem?
I will discuss this on my Livestream this evening 10/24/22 @ 5:PM (pacific) over on RUclips , come check it out ruclips.net/video/bHwhvet7lrM/видео.html
Ice on the ceiling tells me there is an issue with the bimetal defrost, or like circuit.
The whole system only has those 3 fuses on the disconnect switch !!" why does the control circuit not have its own fuse ? if the heaters and fans had there own fuses then you would see them blow before the main fuses so giving you an area to concentrate on. I've said this before and I'll say it again, the electrics on most of your cold rooms it very old school and very hazardous in my opinion. Great videos to watch and you certainly know your stuff 👍👍
man i wish a boss like u! mutch love from Turkiye!
Sometimes I will install temporary fuses in different parts of the circuits to try to narrow down where the issue might be. You adjust the amperage of the fuses accordingly.
What thermal imaging camera do you use ?
I don't remember if he paid close attention to it, but he has a vid showing all his truck equipment over here: ruclips.net/video/H_21k-MIxus/видео.html
I use the flir one pro
Do you ever turn the system off and check ohms, L1 to ground, L2 to ground and L3 to ground (post contactor) and post heater wire on the defrost timer. Sometimes it may turn up some numbers that give you a good clue on the direction to look. Sounds like the blown fues was load induced but what load...... also, was it 1, 2 or all 3. If its only 1 and lets say its on L1 while the evaporator is on L2-L3 allows you to rule out the evaporator. But if its on L2 and L3 then that would be a good place to start. Obviously running the compressor on a single phase if L1 went out would take out another but at least it is a starting point.
Hey is it possible for future videos to show the exact terminals you’re testing? Thanks for sharing your knowledge!
10:29 you guys over there don't use ferrules on flexible cables?🤨 (asking from Germany)😇
The americans is still back on the stone-age when it comes to the electrical components...
/A crazy swede 😁
And wire nuts too, eh?
@@joehead1294 Yep, we use plastic wire nuts and plastic coupling boxes, never open connector boards in cold room and freezer evaps...
I learn so much from here. Im a auto mechanic in new zealand and i feel like i could almost become a hvacr technician
There should (really) be a plastic bushing where the connector enters the switch (or j-box), especially when the wires make tight bends close to the threads
On heat tape you can meager it for grounded and insulation test
Hola soy admirador tuyo , siempre veo tus videos !! olvidaste revisar el valor de los fusibles y que tipo de fusibles GH, GG etc, las curvas de disparo en el tiempo...siempre teniendo en cuenta el valor Iz del cable (corriente admisible que soporta ). Probaría yo el valor del fusible , para mi tiene un fusible que no es de las caracterisiticas adecuadas ...Podria poner un protector de alta y baja tension (si la tension cae repentinamente , el amperaje sube y si el fusible no es el adecuado su disparo en el tiempo va a ser mas corto.,y si la tension cae varias veces al dia el fusible toma temperatura paulatinamente ...me gustaría saber como resolvés este problema ..Soy de Cordoba-Argentina , gracias por compartir todas estas cosas ..
I'm not a fridgey or a sparky (unfortunately), so far be it for me to criticise anything. In fact, I love your methodology, very systematic and thorough (my engineering background is satisfied).
However, a couple of other thoughts that might be useful: I would've loved to see the current draw while you started and ended the defrost cycle. Not sure how that unit is wired, but maybe it's starting the defrost while the compressor is still drawing a load and that's being an issue? Unless the fuses are sized big enough for that
We actually have a Fluke 3-phase energy logger at my workplace that is suuuuuuper handy for these sorts of issues, we can chuck it on and log voltage and current on all 3 phases over time to show if the power is bad. Could chuck something like that in a sheltered spot on the feed for a month or a few, bring the data back in to the office and check the supply is smooth and stable - especially if it pops another fuse while it's logging!
The other thing that came to mind is perhaps might be worth checking the phase rotation at all of the 3 phase equipment. I've seen where people have fixed issues like that at the unit where they noticed it, then someone comes along later and notices a phase rotation issue in a different spot and fixes it there - but if it's fixed in two spots, it's clearly un-fixed.
On that note, the blue incoming in that disconnect switch has WAYYYYY too much insulation stripped back! At my old workplace that would be an instant fail and do it again.
But, I also vote the switch that's flooded!
my money is on an intermittent in the compressor given the current draw difference if that is a 30A fuse you should be seeing actual marks if there was a cable shorting out
Because the issue is intermittent, I believe all of those minor issues piled up, and under occasional "perfect storm" conditions the current flow is just enough to blow a fuse.
I vote walk in switch. I would also suggest phase monitor at condenser.
I'm going with that switch. It was wet, once that happens it's done I wouldn't have been left it that way after seeing those water lines
Great video Chris, is there a sump heater on the compressor through a normally open contact?
I’ve had that give me grief in the past.
Not sure about the regulations in the states but here in Australia sheathed heating elements are allowed 10,000 ohms ir and everything else is min 1Mohm.
Would love to see the follow up on this one, thorough inspection mate 👍🏼🙌🏼
Ok, I would be looking at the breaker in the panel that feeds the disconnect box. If it is rated at or below the fuse ratings, then it should be tripping with a short. You could simply have a bad connection causing single phasing. If that's the case, then the amps would go sky high on the compressor and blow a fuse. An ICM450 phase monitor would be a good investment and can record single phasing events.
You are going to have a lot of egg on your face if changing 6 or 7 year old equipment doesn't fix this. I would expect at least 15 to 20 years life expectancy.
Man where do you get customers who let you replace equipment when you can’t find electrical short?
I would install non electric defrost timer so next time it shorts you have an idea where the issue is
Bad connection is not going to cause to blow fuses on single phase side
This equipment is in really good shape compared to what we work on,
The customer makes the decisions, I just give them a repair quote and they choose what they want, they also purchase their own equipment so they often choose replace over repair as they get a warranty with new equipment
@@HVACRVIDEOS Chris with your attention to detail and proper practices this equipment should go for 20 years.
I Would try insulation testing the wire that goes thru that switch. Switch closed of course.
That crank case heater can do it
Awesome video, 👍🙌👌😊🍀🇭🇷
Your defrost heaters can change the insulation value as they heat up but if your tripping a breaker your looking for below a meg. Everything changes insulation with heat and it can be a pain but as for values I've had brand new elements that were below 2 Meg and worked fine? We're told they should be over 5 but if you can't buy one that high what do you do??
hello wanted to let you know that your exhaust fan playlist has some doubling of vods and a vod from another youtubers channle
“Fly aways” is the main reason why you need to use wire ferrules on the terminations.
I was thinking that those should have ferrules also not only for those "fly aways" but to prevent the crushing for the wires that might break off from the end and reduce the amount of connections still attached to the rest of the main wire.
@@lazytv4318 Yep, usually those very fine multiple strands get spread out by the screw, so only few strands actually are pinched by it. It causes huge current derating and builds heat under considerable load.
10:20 thats why those wires require a ferrule when using them in a screw down connection
I’m betting on the ecm motors, those things are junk. Please keep us updated. Thanks
the fuse they are changing out is it on the low phase?, my best guess is an intermittent brown out on one phase
what about brown outs or storms? I usually install a phase monitor for that
Is there a spark between the compressor connector and the ground sign @4:05 ? It is in the pause after you say "Trending"
Wow, good eye! It is indeed a spark. I saved a gif of it in the link below for those who are curious. Maybe this is the issue?
bit.ly/3CZ36gm
I will discuss this on my Livestream this evening 10/24/22 @ 5:PM (pacific) over on RUclips , come check it out ruclips.net/video/bHwhvet7lrM/видео.html
Is that factory wiring on the contactor? If a tech did the work he needs some OJT.
What about installing a Digital Voltage Monitor?
sir, I have new installed an walk-in freezer ,when go in to defrost system pump down , the compressor kicks on and off about 5 times and then stops. what do you think ? leaking selenoid or bad low-pressure switch? or can you give me some ideas on where to start?
That’s a pain in the ass that these systems don’t have more individually fused circuits. It’s way, way easier when an individual circuit going over current blows a fuse for just that one circuit.
I had a pumpdown solinoid coil intermittently shortin to ground once nobody could find that was tripping breaker. Replace entire unit not even a decide old w out checking that?.. naah
Never used one so I have no idea what I'm doing, but, should you check each leg of the compressor with the Megger?
I've noticed you using an sc460 and an 1587sc. If you had the chance, would you still buy both, or would you buy all the bells and whistles for the 1587sc?
Is better to install ferules on cables
If the previous two fuses blown were on the high voltage leg, and that leg corresponded with the high amp leg on the compressor, would that make that leg on compressor motor suspect?
1Mohm is good, 10Mohm and above is great. No problem there.
I will discuss this on my Livestream this evening 10/24/22 @ 5:PM (pacific) over on RUclips , come check it out ruclips.net/video/bHwhvet7lrM/видео.html
🇺🇸👍💪❄ Great discipline and patience 💪
If i used that much time on a working system some of my former bosses would go nuts
I do see where you're going. You don't want to be paying someone to just roam around changing fuses all the time
The intermittent things like that in electrical will drive you crazy.
"Be careful, obviously" (bare hands)
I'll never understand why stranded wire isn't ferruled in this country.
I've been using them for years, I'll never go back to just twisting it up and jamming it into a contact screw.
No auxiliary Chris
I will discuss this on my Livestream this evening 10/24/22 @ 5:PM (pacific) over on RUclips , come check it out ruclips.net/video/bHwhvet7lrM/видео.html
North pac mechanical in oregon would of waited tell the 30 th time to investigate
why not using ferrule?