How A Typical Refrigeration Cooler Works - Pump Down Refrigeration in 3D
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- Опубліковано 29 кві 2023
- In this 3D video, we show how a typical refrigeration cooler works and focus on pump down refrigeration. This video is narrated by Corey Cruz (BadTXV on TikTok) and shows the refrigeration cycle and automatic pump down for a medium-temp R-404A walk-in cooler.
Automatic pump down is a common control strategy used in refrigeration. It automatically pumps refrigerant on the low side of the system into the condenser and receiver whenever there isn't a call for refrigeration; common scenarios include the defrost cycle and when the box temperature has been satisfied.
Pumping a system down protects the compressor by preventing refrigerant migration during the off cycle and keeping vapor refrigerant from cooling and condensing to a liquid in the compressor. Liquid refrigerant in the compressor can severely damage the compressor, including causing mechanical wear and flooded starts.
An automatic pump down system has three main control components: thermostat, liquid line solenoid, and low-pressure controller.
The thermostat is typically mounted at or near the evaporator head unit in the box. Its sensor reads the return air temperature. The thermostat's relay contacts close on a rise in temperature, causing power to pass through the contacts to the liquid line solenoid.
The liquid line solenoid (or pump down solenoid) is installed on the liquid line of the system and may be at the evaporator or condenser. During a call for refrigeration, the liquid line solenoid will be energized and will open to allow the flow of refrigerant. It closes during the off cycle and prevents refrigerant flow. The receiver, liquid line filter drier, and sight glass usually come before the liquid line solenoid; a receiver stores excess refrigerant, a liquid line filter drier removes contaminants, and a sight glass will let you know if there is a full line of liquid going to the liquid line solenoid and metering device.
The low-pressure controller is installed at the condenser and will be wired in series with the contactor coil. It will cut in or out based on pressure conditions. When setting the cut-in and cut-out setpoints, you will need to consult the manual and be aware of the refrigerant used in the system. To obtain the cut-out setting, subtract the differential from the cut-in setting.
When the box temperature rises above the thermostat set point, the thermostat relay's contacts will close and allow power to travel to the liquid line solenoid, which will then open and allow refrigerant to pass to the evaporator. With refrigerant flowing and the pressure rising, the pressure on the low side should then exceed the cut-in setting on the low-pressure control. The contactor coil should then close, completing the circuit and allowing the compressor and condenser fan motors to start operating. During the off cycle, this process is reversed, and the contacts open to remove power to the liquid line solenoid.
Pump down begins with the compressor and condenser fan still running. When the suction pressure reaches the cut-out setting, the contacts in the pressure controller open and de-energize the contactor coil, turning the compressor and condenser fan motors off.
Many medium-temperature applications don't have a defrost clock and merely defrost during the off cycle. 120v single-phase line power will energize the evaporator fans, liquid line solenoid, and thermostat; the evaporator fans will continue running during the off cycle, and it will supply power to the terminals and their respective wires to the components on the low side of the system. The condenser will receive 208v three-phase power.
When the box setpoint is satisfied, or the system is in defrost, the thermostat will prevent power from energizing the liquid line solenoid. Refrigerant will not pass to the evaporator coil, and excess refrigerant will collect in the liquid line receiver. The pressure will drop on the low side of the system; the pump down procedure will continue until the pressure reaches the cut-out setting. The power will then be removed from the compressor and condenser fan motors.
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Bravo!!!! That was an amazing demonstration!!! I love The attention to detail. HVAC School always delivers superheated content!🔥🔥
As someone who is transitioning to Commercial Refrigeration from Residential Service, I highly, HIGHLY appreciate this. Thank you so much.
These 3-D animations are going to help a lot more techs it is so helpful to see what is actually happening. I wish more schools would implement this
Thank you
That was a brilliant presentation.
Excellent demonstration and explanation, thank you
As someone who doesn’t know anything about refrigeration, this was an amazing explanation. It answered a lot of questions and gave me a big inside in case I ever have to do refrigeration
I got into the HVAC in the mid 70s , I was in the commercial refrigeration side of our shop. We served malls and restaurants. Man if we would have had access to a channel such as yours I would have become a well-seasoned tech much quicker. You do a great service to our industry. Keep up the great videos.
Wow I love these 3D simulators. You can’t get much more accurate then this. As a Hvacr tech I am new to refrigeration and becoming more knowledged in resisdential but the next step is commercial refrigeration. Thank you for taking this time to ensure we understand these presentations
that was the best explanation video i have ever seen
One of the best if not the best video explaining the Automatic Pump Down System, Thank you very much!
Absolutely the best illustration available! Thank you.
I really appreciate the information you are putting out for the hvac community. Please keep doing this videos i love it.
That was great. Thanks to all who helped put this together.
By far the most detailed video on how a pump down refrigeration works thank you. Keeeeeeeeep them coming
👏👏👏👏 Wow, great job. Thanks for all you guys are doing for this wonderful trade.
This is great. Sending this link to my work team.
I'm in Miami
Appliance Repair technician. Mostly refrigerators. I want to become an AC technician. A lot. Best chanel!
You mean refrigeration technician
This is amazing. I’m a seasoned resi tech but not so much refrigeration. I had an idea but this just clarified it tot the point that I can properly do service on them with confidence.
THAT WAS AWESOME!!!! THANK YOU SO MUCH FOR THE VISUAL, VOCAL ILLUSTRATION!!! MUCH VALUED!!!
As a residential guy in refrigeration now, this was a big help. Had a bad first day thinking too much like a AC guy.
This is a great video and animation, thank you for taking the time to share this with the world, we need more technicians in this industry!
This is a fantastic rundown on pump-down system. Great job guys.
I love these 3D videos. Great, as usual. Nice work, guys.
Omg! This is the coolest thing ever! Love the 3D simulations and there is so much good information in here. Thank you
Thanks for the 3D presentation
I'd wire those two 120 volt, permanent split capacitor evaporator fan motors to a series parallel contactor that runs them in series during the off cycle and parallel during the cooling cycle. Permanent split capacitor fan motors run very well at reduced voltage, running slower, consuming less power, and running cooler. This will save energy, and reduce the heat load on the system, while still providing plenty of air circulation during the off cycle.
Amazing 3D-illustrations! Excellent presentation! THANK YOU!
This is such a great video…i have my cfessa certification course at the end of this week. Just refreshing from the bottom up and I’m so confident, thanks for this video. Definitely one to save while I’m in a pinch!
By far the best explanation of the refrigerant cycle! 😮👍🏼 Love the animation also ❤️💙
This was an excellent demonstration. Very helpful for me to understand better whats going on. I am also coming from residential air conditioning. Thank you!
Best video out there on this!!!
clear and simple .. great job .. BIG thank you
Thank you I have begun to focus more on the commercial side as of recently. I have done this to expand my options and skill set. I appreciate all that you do for the HVACR industry…… GOD bless you all,stay safe out there brothers….and remember to never rush to judgment. Thank You!!
Keep up the great work brother :)
Very good thank you guys 🙏🇺🇸🙏
It will be cool to show how to troubleshoot the critical components on this systems,
Great video!
You guys crushed it
Brilliant video, thank you!
That is how you show the proper operation of a medium temperature cooler. 🎉
This is absolutely amazing thanks for the Gem 💎
Thank you for making this video the time and attention to detail is amazing this will serve as a great reference for new techs and experienced alike!
cheers gentlemen!
Thank you!
Extraordinary teaching! Keep up the good work ❤
I think I would be really cool if you made these type of animations to help people understand and read schematics.
Thank you so very much for your effort making this video. It is the best video I’ve seen. Great work.
This one was a good one. Very well pictured, very detailed and very well explained.
What a great video HVAC School , I am pretty sure a lot of people including me appreciate the work put into making this video !!!
Awesome video!
It really explains the sequence of operation
Excellent,Excellent MASTER!!!!!
Great video! Hope you cover more refrigeration sytems. Would love to see low temp and modern EEV systems. You people are the best at education.
Thanks, Corey👍🏾
Great job.thank you.
THANK YOU!
Thank you so much
Very good demonstration thank you this helped me understand
This is such a great video! I’m very new to refrigeration, but at my work we have so many issues with the many many HVAC units, and several walk-in coolers. We can’t seem to find anyone that can reliably repair the walk-in units, they either say the entire unit needs replaced, or they try and fail over and over again. Talking to them it’s clear they don’t actually understand them, which makes it hard to work on them. I’ve taken over the maintenance as far as changing filters, keeping condensate drains working and pans clean, replacing start capacitors when they fail etc, so basically I do what I can before calling for help, then watch and learn what I can. I have installed smart thermostats everywhere, since the employees like to turn some units to heat while others are set to cooling, and now have it automated so if one is changed to heat, all the others do as well and vice versa. But this walk-in is driving me crazy, it seems to want to freeze up every week or so, I have widened the temperature setting so it stays off longer between runs giving it time to defrost more, which seems to be working, and also have sealed up a few air leaks where new lines were run in and not sealed up which seemed to help a lot according to the temperature sensor I’ve installed which logs as well so I can see the patterns. But, what this video has opened my eyes to is the fact that the outdoor unit NEVER turns off! So I will be looking into that when I get to work tomorrow, thanks so much for your effort.
Make sure the door seals are good and leaving the door open for long periods will freeze it up too
Fantastic! I wish these videos were around when I was in school.
well done gentlemen
Wow. This is good. Thank you.
Great job
Awesome video learned a lot about the wiring and sequence of operations with this video
This video is awesome, helped me a lot thank you so much guys
Awesome video! Thank you!
Amazing guys! Great Work ! Just Fantastic! Thanks guys! Well Done!👍💯
Great video
Very good basic refrigeration video
Great video, thanks for such a good presentation👍🏼
Hello , here in miami fl , thanks for the video
Just awesome
This is gold
this is so good that even I as only a residential HVAC guy can understand it.
fantastic video!!
Very well explained 💯👏🏼
A M A Z I N G L Y GORGEOUS......WE LIKE YOU GUYS THANK YOU AGAIN KEEP UP 😊
So cool no pun intended.
I actually can comprehend that theory now. Thank you.
Thanks for posting need I can visualize the step procedures, now that got me to go get a back up solenoid operated weight refrigerate scale its just one of those things to own two of! Love the lesson shows! All day I'm to words that teach me! 🙌
Watching from miami Florida
Awesome ! Thanks
Very well made and informative video!
Amazing demonstration and explanation!
Great information as always!
Thanks for sharing
WOW... That is awesome
Thank you!!!
Amazing video!!
Thank you so mach
Great video!
Amazing Video!!
Amazing video
Thanks!
Great video thank you
Great video and info. Thank you. "Educational".
I'm just watching again after sending it to one of our guys. I'm not sure if I commented before, but this is a great demonstration.
Amazing video, very good
Thanks alot your video and explanatiıon. fantastic work.
Thank you!!👌
Great explanation
That is a great video!!
Great video 👍
Man! This is great schooling. Way to to go guys. Everyone be safe out there. Very helpful some calls can be a random account with a walk in box 😅
FYI - Not only refrigeration systems that have a pump down feature built into them, but many manufacturers such as APC, Bard, Liebert, Stulz, and Unlflair all do as well…