Supermarket Refrigeration - Troubleshooting Walk In Freezer Running Warm (Electric Defrost Issue)
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- Опубликовано: 11 сен 2024
- 15 Step Guide
• Supermarket Rack Refri...
1) Air flow
Are the fans running
Is the honeycomb plugged
Is the coil Iced up
2) Temperature probe
Verified temp probes in a cup of ice water (33 Degrees)
3) Is the controller calling for refrigeration?
Did somebody put in a manual off or on.
4) Rack pressures
Discharge
Suction
5) Check Rack safetys
Oil safetys
High pressure
6) Check Condenser
is it plugged
Are the motors working
How many are out
7) Receiver level
Rule of thumb 20% summer
Rule of thumb 80% winter
20% at 70 Degrees
But above 0 is probably ok
8) Sight glass
Is it flashing
What is the load On the system. Hot day ? Cold day?
9) Rack filter dryer
Take a pressure Differential.
5 psi rule of thumb.
10) Rack circuit Ball valves
Are they open.
11) Liquid solenoid / suction solenoid / epr
Check function
12) Pressure at the cases
Does it match the case spec.
Rule of thumb, evaporator coil 10 degrees under the required temperature.
Is the liquid 100 PSI above the suction
13) Case hand valves
14) Case filter dryer
Take a temperature differential
5 - 6 degrees rule of thumb.
15) Superheat
Does it match the case spec.
Is the case close to temp.
Is the TXV screen clean.
Test the TXV
1. Very realistic walk in freezer you were lucky you could see the evap coil.
2. Again realistic no roof hatch key.
Common problems in the trade.
Thank you for your videos.
Best hvacr channel on RUclips
Hello friend, I am a cold storage manufacturer from China, nice to meet you
I've been watching your videos for a while, I like the way you explain things and I find your content fascinating
Can't get enough of your videos brother, need more
Overstocking plus 9 times out of 100 yeah, employees leave the door open or bad door gaskets, unfortunately.
Fortunately.
But the video. And the process you go through, to good learning a tool.Thank you
Gendron HVAC-R is a refrigeration gangster!
Nice vid!
Your videos are what got me into supermarket refrigeration. I try making notes whenever you post, but i keep loosing the papers lol
Glad to help !
Your videos are great, always look forward to your content. Always great explanations and walkthrough. Keep it up!
i like your meticulous troubleshooting steps. the electric defrost heaters they manufacture nowadays are cruddy. they die so often. I actually learned today that you could amp draw the line out on defrost contactor to see if you have a shorted defrost heater. If you know how many loads are on the circuit, and how many amps they draw, you can figure it out. had one reach in case with 3 heaters drawing 16 amps (those heaters usually draw 8amps), stripped the case, lifted the deckpan-- there it was... a mini explosion on the front heater
Great video, I appreciate you for teaching and passing on what you know about this stuff. Helps us new guys learn a little extra.
Thank you for sharing , got new subscriber
Man what a great vid and step by trouble shooting. I install Vrf heat recovery units, and do some very little service in refrigeration but when you don't do it everyday its a bit of a task. Thank you
Watched one video and immediately subscribed. Great video brother.
Thank you for the encouraging words :). I hope my videos help
Learning a lot from you. Thanks
Technically with electrical standards, NFPA 74 I believe I could be wrong but with that high voltage of 460 V it’s highly recommended that upon approaching that cabinet and opening you should actually be using level four arc flash protection until that high voltage is isolated at which point you can then use your level 2/protectionand troubleshoot much easier of course not everybody does this but for safety purposes and art flashed explosion can be very very dramatic
You're probably right,
I should probably be using ark Protection.
Thank you for your comment.
Promoting safety and getting home to your family is a high priority.
Not just dramatic, at one place I used to work at, the main electrical room distribution boards, some of them had signs on the doors warning "Caution arc flash hazard" and "NO safe PPE exists". Which means if you opened the door, and you were within 200' of that panel, even wearing a space suit, if something blew you'd still be blasted and cooked. The building had switches to put that part of the gear into "maintenance mode" where it did something to reduce the available short circuit amps. The you could suit up, grab your hot stick, and pull a primary fuse or whatever. The reason for this is the transformers feeding the building were so large, the amount of available short circuit amps was ridiculous. Even in the low voltage stuff (120/208 3 phase) panels, all the circuit breakers had to be at least 65 kiloamp rated, which are harder to find than like your standard 10 kiloamp or 22 kA breakers you would find in small commercial or residential electrical panels. 10,000 amps of arc flash of 480 volts is very bad. But 65,000 amps you're toast. If you do the math on that, that's like 30 megawatts of power. Of course, the circuit breaker for the transformer would instantly trip, but that's still a massive explosion.
@@gendronhvac-r1269 The hazard depends on the available short circuit amperage. What you can do is find the main breakers that feed those cabinets and look at their ratings. If they're like 10kA or 22kA standard breakers, then there's probably not a huge amount of short circuit current available. Then you can check how long and what guage of wire feeds those control panels and do some calculations of what the worst case line to line short circuit current is, and at 480volts. Then you can look up the tables that show you the safe working distance, and required PPE. When in doubt, consult an electrical engineer. In new construction buildings, the avail short circuit current is required to be labeled on the doors with OSHA req'd arc flash, and caution high voltage labels etc.
But like I always say, if I go into a store, and fix everything I find wrong, we'd have a new store, and that's just not feasible for a customer with an older building. Not just financial issues but down time, how long would the store have to be closed, the customers would go somewhere else, etc, and possible long term loss of market share.
Excellent
Where in Massachusetts are you bro
I have a video request. Can you possibly do a explainer/demonstration video on how to check oil pressure on a high/medium/low temp single circuit refrigeration system with a semi-hermtic compressor? It probably sounds dumb but I need to expand my commercial refrigeration abilities and this is one thing I don't understand and haven't done yet. I don't want to f up a customers equipment trying to "figure it out" if that makes any sense. Thank you either way.
I can try,
I don't work in the field much anymore these days.So that's why I come out with content so infrequently.
But if I see it I'll try to do it for you :)
Did I see the rack said Hussmann Atlanta? Are you in GA?
No I am not lol.
That is kinda odd about the rack.
I'm out of new England area
When you’re dealing with 460 V rack systems like that you have to be very cautious with arc flash. Arc flash is a serious and very important thing to consider. If you don’t believe me watch some videos on ark flash hazards, and how dangerous they can be be safe everybodyyour protection you should be at least having a level two flash protection when you’re working on these these racks
Thank you for your comment.I totally agree. !
Not sure you noticed that the right side evaporator fan was inoperable and the unit is flooding back on the suction line!!
It was flooding back because covered in frost = no airflow. I was wondering why he didn't mention the fan motor, that's one thing I don't like when I'm checking refrigeration is a bad motor. If that evap doesn't have decent baffles between the fans, the fans adjacent that are working will just pull air thru that dead one, and not get as much airflow thru that side of the coil. They all have some baffles, some brands have big gaps though, so it's not as compartmentalized.
Yeah it was flooding back because it was Frosted up.
And I think I just missed the fan because it was two in the morning. 🤣
I'm still learning everyday :)
Could you go over that type of oil system on that rack?
I am not in the field as much so it's kind of difficult for me to make more videos I try as best I can.
But I do have a nightmare royal failure video.
And then I believe I have an oil system in a nutshell video.
Those should hopefully help you
Praise the lord you know Jesus
Can you do ohm with the electricity on?
No you can't!
It is dangerous.
What actually happens is your meter will send a small amount of current Through the Wire. And based on how well the current flows the meter will give you a value. So if your system already has a current or voltage present it just will not work and it will probably mess up your meter.
Hope that helps :)
We use LOTO procedures with 3 phase every time. Not worth your life for any amount of money.
Definitely A good idea :)