Maintain Discharge Pressure With Condenser Flood Back In Low Ambient Conditions
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- เผยแพร่เมื่อ 28 ส.ค. 2024
- Low ambient conditions can cause head aches with air conditioning and refrigeration systems. Using condenser flood back to maintain discharge pressure is a great way overcome this problem. Using a combination of an ORI valve and ORD valve can accomplish this task. It will maintain discharge pressure by flooding the condenser while maintaining flow through the system.
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This is just one way to control discharge pressure
Headmaster/OROA, yeah?
These are the videos that help me so much, a couple guys in my 1st year class watch you. We all talk about how much you help us . Cheers , keep up the videos
Very cool, I appreciate the feedback man!
Never heard of this ! Thanks for the info . A way I learned as well is with a fan cycling pressure control.
That works in some applications as well
I like theses videos! I see this type of set-up often in commercial refrigeration here in Québec!
Thank you, yes very common for sure
@@HVACKnowItAll I've been following you on IG and Facebook always great stuff on your social media 👍and it's a great idea to do YT video! There's alot off missing info on hvac stuff on the web and you might be the first one doing it on youtube 👌 keep on the good work
I really enjoy your videos by far some of the most informative on the internet. One thing nobody ever talks about is ORI adjustments, signs of additional charge when adjusting, adjusting in diffrent temperatures. I have a system calls for 13 lbs of refrigerant for but it doesn't specify in manual on what this includes or doesn't include. So i guess the ultimate way to verify if enough refrigerant is a clear sight glass with the ORI choked out to hold refrigerant back. The recommended 13 lbs i was getting a decent amount of vapor in the site glass. Ended up with a clear site glass then dialed the ORI back to 150ish after pitting in 14.7lbs. Still have a very high superheat but i dont want to dump even more refrigerant unless i absolutely know it is necessary. The reciver holds 22lbs of r404, and with the r449a i have room but what would be the correct charge. I believe the 13 lbs is meant to cover the condenser flooding and winter charge. I ended up at 14.7lbs to clear the site glass. So i guess the question i can never find the answer on is proper technique to adjust the ORI and adjust the charge. Should super heat even be a consideration in the charge with the ori or should the ORI be used to help the eev achieve the proper superheat with the called for 13lbs. Or should additional charge be given to push up pressure first. Should i just give a full 3/4 reciver which would be a 16.5lbs. It would be nice to get someone elses thought process on how they tune a system with an ORI to overcome issues like high superheat or low vapor line pressure on start up. I would hate to go drop a new larger EEV to overcome the high superheat when I could have just tuned the ORI, increased the charge or fix something stupid i missed.
Fantastic Video Today. Love it.
This a really great style with the diagrams and explanations.
I often watch your channel but really like this format.
Looking forward to more and hopefully persuading you more towards refrigeration, racks and controls, etc.
Excellent work.
Thank you, I appreciate that. I have no real experience in refrigeration racks, that's why I get informative podcast guests for that sort of stuff
@@HVACKnowItAll still good stuff here. Anything on uncommon controls rocks.
I do that differently. I install a low ambient pressure switch to stop condenser fan motor on cool days. Once pressure build up, pressure switch closes allowing the fan to come on. I adjust the pressures I want from the switch depending on the type of refrigerant and sub-cooling recommended by unit data plate. My goal its to maintain 100 percent liquid in the liquid line.
On systems without a receiver this can be done, but I would recommend fan speed rather than fan cycle. Fan cycle creates large pressure swings.
@@HVACKnowItAll understand your point. I did just mentioned one of many ways. Am considering that some condenser unit have multiple condenser motors, so the pressure swing will not be so dramatic if doing a sequence with multiple motors.. You right if condenser had only one fan motor. Of course, a fan speed control its just a different way, and in which I recommend. Injecting hot gas will affect the subcooling ( no condensation ), and refrigerant will just pass trough the meeting device ( TXV , orifice etc)
Thanks for sharing. I will probably not come across this setup but I do like learning something new.
Never say never...and you're welcome
It will be great if you can make a video about electrical control valves when used instead of mechanical ones like ORI. Thanks!
Great video and explanation.
move to Vancouver, get hired at Refrigeration Training Institute, profit. You're a great teacher.
Great explanation!
Thank you
Awesome video, never seen this type before. Usually only headmasters. What are the pros and cons between the two ? Headmasters and these. Thanks
Surprising we still have R22 around.
Good video..thanks
Great video thank you
I appreciate the feedback, cheers!
Excellent teaching
Thank you!
Nice video and great knowledge.
Thanks for sharing.
Thank you and you're welcome
That's super interesting stuff I forgot from trade school, thank you for the reminder . The chillers i work on only use fan speed control , but I would imagine that up in Canada maybe because its gets so cold you fan speed is not enough to build up hp ?
We so use fan speed here too...just depends on the engineer lol
Thanks a lot ! it's really helpfull !
Great explanation! Thank you!
You're welcome thank you
Great Technical informative video. Thank You
This guy is a goat
So…ultimately the txv will help the pressure build back up as superheat lowers in the evaporator…right?
hi, can you make videos on controlling PLC's for refrigeration please, like compressor, evaporator, condenser, exv control management
What is the difference between this type which seems similar to Headmaster valves and a Hot Gas Bypass which loads the Evaporator
I would like to know why he has chosen 225psi as the pressure for the ORI? That corresponds to an ambient temperature of 110 degrees with R22. Can someone explain how we got about choosing ORI pressures in relation to keeping a certain head pressure? Are we taking into account an ideal ambient on a warm day with an extra 30 degrees for the heat of rejection from compression?
225 psi corresponds to a running temperature of 110⁰F SCT, mot outside temperature.
Is this the same as head pressure control valve in commercial refrigeration ?
Awesome info
Thank you
would ORD or ORI make it difficult to get the correct subcool measurement when charging the system, do we measure subcool same way at the outlet of condenser or inlet of receiver, or would be tricky with ORI,ORD SYSTEM,DO they fail to open or close .Thanks
When working with these valves, you have a receiver. The receiver should be supplying a full column of liquid to the metering device ensuring enough subcooling. However is there is a low charge or valve issue, it can throw things off.
what about a liquid pressure transducer to control a variable speed condenser fan motor? not just a switch. why is this not more common. i don’t understand. we have head pressure control commonly used on water source refrigeration that mechanically controls heap P via water flow through heat exchanger. i’m sure there is a reason but i’m not understanding. why pay to run a condenser fan motor 100% if your just going to bypass condenser coil this or other ways
In extremely cold climates, if there's no flood back, you can't build enough pressure. Even if the fan isn't running at all!
Solid teachings .so how does the headmaster compare?
The head master is one 3 way valve instead of two 2 way valves
Thank you for the info.
When the O.R.D opens. Is that not sending that hot refrigerant to the evaporator coil in turn now heating the space ?
When the ORD opens it's sending hot gas into the receiver pressurisizng it. The metering device stills sees liquid
The "dip tube" on receiver is down in the liquid (as long as you're charged) sending liquid to metering device.
Just to have a better understanding...ori is set to 225 in your example so does that mean the ord is opening around 205 with the 20 psi differential ?
Correct
it's called headmaster lol great information
No, a head master is one 3 way device, this is two "2 way" devices.
Headmaster is a modulating device, a balancing act like a tev / txv modulates.
Any line size/flow rate differences between the ORD and condenser so condenser can still build pressure?
Yes ORD line is usually a bit smaller
How much refrigerant does the ord let through while the ori is closed?
Full flow after 20psi dif
Can the ori fail and hold back and cause high head?
Yes
Love it. Good work explaining it.