Man, if I understand correctly, you are teaching HVAC students as a part of your activities. So, I wish I had a mentor like you years back when I was at the beginning of my way. You have a great talent to put the whole story short, clear and easy to follow. Your students are lucky to have such a great teacher.
Great video ,,for the technician out there ,,take a black marker and mark the bottom of the TXV before you start adjusting so you know where you started ,,make half turns ! Left or right so you can see where your sub cooling is going up or down..I wish On the videos you would show how it works
I really enjoyed this detailed presentation on the Expansion Valve! This Video will go into my most valued folder as an accurate reference point! Thank you much.
Awesome video. Glad i watched. Found a 5 year old R22 4 ton split A/C system with a closed txv. Flat sensing bulb. I weighed the charge in and my suction and head were low. Ambient temp in the lower 70's. Need to go back when i have a good ambient to check the superheat and sub cooling. Parker said the valve comes set @ 10 degrees superheat.
Great video.Thanks for imparting and sharing your expertise with us. A request could U do a video on selecting a TXV for a particular evaporator coil what parameters would I need to consider.
I go off manufactures specs txv’s coming preset from Factory. I think adjusting can make things worse, replace with new one better safe then sorry instead of tinkering with it and trying to get it dialed in. Week later your back on the roof and the comp is flooded.
It’s also important to note that superheat is pretty important to the compressor. It’s important to know what your superheat is before it reaches the condenser because if the superheat is perfect at the evaporator but too high at the condenser then that can create an issue.
I love all this fancy equipment now a days. I did refrigeration 40 years ago on 20 tonTurbo Ice Makers 12 plates 12 distributors on a txv and NEVER used a temp probe to do superheat. Simple open txv till it just starts to flood suction, close it to bring frost line back to evaporator, DONE deal you are using all of the evap, and not flooding suction line. And a txv with external equalizer tube that is attached to the suction line at the bulb does just what I explained (it will kind of by pass the temp bulb) till the evap gets established.
Sounds similar to my first boss, he would go further by licking his finger and seeing if it would stick on the outlet of evap. He did this on freezer coils and ice machines.
Hi Ben Brian Great tutorial, I really like watching your studies and I wish I had the opportunity to study with you. Who knows, maybe one day it will come true. I have a professional question. I am a technician of industrial cooling systems. How do I know how to correctly measure subcool and superheat according to the seasons? Is it summer? Does it change? Because it's colder or hotter outside? And what is recommended to be in cold rooms at low temperatures? 4 degrees Celsius and minus 18 degrees Celsius Thank you very much appreciate it..
0:59 - The purpose of the thermostatic expansion valve is to maintain the correct amount of refrigerant in the evaporator coil for any change in load conditions by assuring a constant superheat at the exit of the coil. When the load conditions call for more refrigerant in the coil (such as during a hot pull-down when, say, the door of a walk-in is left open for an extended period), the rise in temperature at sensing bulb will push the valve further open. 12:34 - The number of degrees of superheat is directly proportional to the volume of vapor within the coil - the more vapor taking up space in the coil, the less room there will be for boiling refrigerant (and the less efficient the box will be). Just sayin’
just a little about dirt ,,,i ran into so many contractors about brazing with nitro ,,,,they say oh i never had problems or call back because i did not use nitro ,,,,,then it becomes an arguement ,,,,and i am talking about guys with years of experience ! ,,,its all about the money first , get my house cool for as low as you can ,,,lol i am old school i was a certified welder with over 30years experience when i decided to go to school for HVAC . every tech tries to impress the other LOL ,,,,,just saying this school is good stuff for all of us ,,,,i am retired but love to learn more
Very good explanation on adjustment. Best check airflow and superheat at evaporator. Also ^ TD . I have only adjusted valves in refrigeration units, walk-ins and freezer. Ole style Q body valves were much easier to adjust and maintain S.H. For the smart super techs, if you listen to Bryan Orr might learn a wealth of knowledge.
@@Z-Ack spw turns 1/4 turn at a time then wait 20 or 30 minutes to stabalize. But you should not have to adjust TXV unless system is mixed matched in tonnage or some long line set. I am not an expert on this but I did stay at a Holiday Express last night.
I'm at a lost of what copeland wants for their semi-hermetic compressors. I know they say generally a minimum of 20 degrees but does that 20 degree apply to all applications or just A/C ? What about low temp refrigeration? or chillers? There's not much info on this. I noticed some applications run high superheat such as low temp and it makes me ponder if these are typical running conditons or should i go after my TXV and adjust it to drop superheat temp. I guess overall having superheat is better than not having any.
Hi I have a 6 Ton carrier split unit with a "Piston" I would like to replace it with a Sporlan TXV (I have the TXV on hand) but I also want to add a suction line accumilator . What size range of the accumilator (in Liters) should I use . Thanks very much
Enjoyed the Podcast ! Works good to pass the time while doing the dishes, also picking up a thing or two here & there. been doing refrig . since 1981, also information on whats going on in the trade sometimes. Thanks for making them.
If I reach the subcooling value to the exact number stated in the label of the condenser's unit charge value which is 10F but the superheat goes to 1 or zero.. should I adjust the TXV valve to increase the superheat value to normal levels??
Thanks Brian, question please, I always have hard times brazing these short necked TXVs, I cannot easily roll them well with a wet rag, I use a strong neutral flame to make it fast but, the rag tip gets burned carbonizing the joint and the valve over heats rapidly, any suggestions? Thanks
Excellent video, You will find most expansion valves are set real close for the proper super heat out of the evaporator. Many factors like laid over coil fins, wrong RPM motor or fan blade pitch can cause fake readings. My question is How much coffee did you drink before filming this:)
6 to 8 ° is extremely low . I’m looking for 15 to 20 degrees superheat at the compressor. I’m not sure why it would be so important to check evaporator superheat in air conditioning refrigeration yes but We are trying to make sure our compressor has good super heat and we’re not flooding the compressor …….. 15 to 20 degrees superheat at the compressor is what we’re looking for
You Stepped WAAAAY Outside of Explaining ANY TXV Action within the 3:00 minute mark for ANY HVAC TECH of 1-2 years ...........you are just speaking to Yourself at that point........KISS!
I'm not a HVAC tech and I enjoy the details. I have gauges and have charged 410 and 22 myself in years past. More knowledge is power. My local HVAC tech came to troubleshoot my Trane and he could not explain to me how to check the TXV. It was replaced once already by Trane and symptoms seem to indicate that it needs an adjustment.
Problem with that is that metal is conductive and what you're trying to avoid is changing the temperature based on conditions other than the temperature of that copper. This is the reason we use cork tape, as it is a insulating material. Remember that the bulb reads temperature, and that the TXV converts that temperature into pressure and back. For proper operation and easier troubleshooting, avoid using a conductive material around the bulb.
ok i just learned this the hard way, 9:00 min in, i was working on a walk in and reading the temp/ psi at the condensing unit, so i think i bungled the super heat. i had i lot of bubbles inside the sight glass a more experienced technician said just add more 404a till the bibles stop and than just a bit more. i did. bit, but now i don't real know if its a leak or broken txv? i should have done a leak check but hind sight is 20/20 i guess.
I am an ectrician by trade but the ac at my house quit cooling. Its not cooling at all. The condensor I think came with the house and it was built in 1987. The inside unit was installed around 2000. Its a 3 ton ac unit 120 volts. It stopped cooling about a year ago and it quit working all at once. The compressor is running and I had a friend check the freon and he said it is low but not so low it should have quit working. I'm thinking it might be the TXV. I have airflow going thru the unit, its just not cold at all. Any idea's
If you have freezer temps it is normal to have a freezing suction line. The evap will have a temp of approximately -15 degrees. If your superheat is 10 degrees then the line temp will be -5 which will freeze the condensation. Check your superheat, if it is in the normal range then it is ok.
What i am always wondering: Is such a TXV fast enough? How many seconds does it take between change of temperature of the refrigeration fluid behind the evaporator and change of temperature and pressure in the sensing-bulb? I guess, that can take half a minute or more.
Good information, good refresher. Boring from a video presentation viewpoint, watching a TXV be turned over and over for 19 minutes. I would expect that from an average Joe, not from a "School". But, still very good information. I got the "How" from this but still a little fuzzy on the "Why and When". Did you mention that adjusting the TXV is the LAST thing to do? And that the charge, clean condenser coil and evap coil, correct airflow through each should all be nailed down first? You may have, I just may have missed it. A have seen dudes just reef on that stem, many turns in one shot. You correctly advised against that. Good jjob overall, thanks.
Failure rate of tevs is fairly low. They can fail. But modern tev's are fairly reliable. They are more like to be destroyed by someone who doesn't know how to keep them cool while brazing.
Mine maintains superheat of 21 degrees with a sub cool of 12.8 degrees with manufactor specs call for 13 degrees for a temperature of 90 ambient, it's a 12 year old icp r22. :)
Well you dont want your evap coil being filled with liquid 80%-100% of the capacity. You want it to the point where in the middle of the coil its vapor (thats what you wanna feel to feel cool)..some people over charge a unit to the point where that vapor point happens at the suction line which at that point its past the blower motor cool air going back to the compressor and not your house instead of cooling you its cooling the copper lines itself ..its just like car you want your combustion to happen inside the engine not at the exhaust thats why you hear and see dumb high school kids now adays doing dumb mods to the cars that make it sound like gun shots thats combustion happening at the exhaust and not at the engine
You say adjusts a TXV to get correct super heat what about adjusting it for Sub cooling? I installed a Danfoss tr6 into a system that had a piston orifice and now I'm having trouble charging to 10 deg Sub Cool. I'm at 7-8 degs and cant get it any better. Oh and it not responding to charge because I've gone for low to over and still cant make the ideal S/C
This is great stuff. But I'm confused. I'm relatively new to the trade. How come when your dealing with a split system they tell you if you have a piston you charge for superheat but txv/tev it's subcooling you go off of? But the valve actually keeps a constant superheat? Sorry for my ignorance just want to better my understanding!
Not necessarily... the TEV causes a restriction, so condensation is normal. Frost is probably an indicator of high superheat. I.e. not enough refrigerant. Just my guess.
One thing you forgot to mention: column pressure. A system, where the evaporator unit is in the attic, or in the basement, creates a different pressure at the valve, than at the ground level condenser unit, the result of liquid in the high pressure line. Old units, with R-22 refrigerant will show bigger differences, then newer units, with R-410, or R-134.
I just had my AC unit serviced and the guy refilled the refrigerant since it was completely empty. Now my AC unit is really struggling to pump cold air - i was thinking of giving this valve a half turn to allow more refrigerant through - is it possible it was reinstalled "too closed"?
I have r507 chiller operating at 1 to 4degC . What is reco. Superheat..I test it once, measure it in the evaporator, suct.temp is -1C then suction pressure is 50psi..according to chart 50psi is -10C . So my SH is 9deg.C..is this right?
I work for a Fluid Chillers inc. We shoot for 15 degrees Fahrenheit superheat, but mainly we don't want the compressor to ice up. Low-temperature evaporators are very susceptible the heat load supplied to them. And even though he calls it a constant superheat valve, they're anything but. As the load begins to drop so will the superheat unless you have an electronic expansion valve. In a low load situation a superheat of 10 degrees Fahrenheit is fine but then as the load increases you could have a super heat as high as 40 or even 100 degrees Fahrenheit depending on how hot your load is. We're on chillers from 68 degrees Fahrenheit setpoint all the way down to -80 degrees Fahrenheit setpoint. I'm a huge fan of electronic expansion valves the stepper motor on the valve is so much more Superior than your silly diaphragm valve
my succion is going into a vacuum opening my low pressure switch in about 30 secs.. I only have a txv and filter drier in my system.. can I say it's either or that's bad?
a question sir, the ac in my car, it is cold at idle but blows warm air when moving/revved. all the necessary things have been replaced with new ones ie cooling coil, condenser, expansion valve, filters. the only thing i havent done is adjusting the expansion valve plus, the low side pressure increases when the engine is revved, can this be the source of my problem? tqvm
The basic rule is: Not enough superheat = not enough refrigerant. Too much Superheat = too much refrigerant. If a TXV hunts a lot check the bulb placement and how well it is attached to the suction line, mount your bulbs at 10 oclock or 2 oclock, never at 6 oclock. Make sure bulb has full contact with the line, you may need to sand off any oxidation or grime that has built up on the copper before mounting a bulb. Insulate the bulb with Cork Tape or Permatape after mounting.
Not so fast ! I agree that low on refrigerant = high superheat The other part can vary. Why ? Mainly because we could run into restrictions for any number of reasons: bad or stuck TXV, clogged or partially clogged strainer, partially stuck pump down valve, restricted drier, etc. There is only one variable that I can promise. IF there is a bad restriction, and if the system is tight AND correctly charged, the liquid (refrigerant charge) will back up into the condensor because it can't get to the evaporator. When you take the pressure readings and temperature readings on suction and particularly liquid lines, the evidence will be far too much sub cooling on the condensed side (because the liquid is back up into the condenser side.) Try this one out: I once had a system that was only two years old but wasn't cooling correctly in 90's. I was told to change it out and replace it. As I recovered the refrigerant, I discovered that the unit had never had the accurator (for metering refrigerant) installed. It was running "hollow pipe". This was the fault of the installer.
@@repetemyname842 You would be exactly right, if you measure temperature right at the expansion valve. In this video, he's measuring temperature at the OUTLET of the evaporator, after the warm air has heated the volume of refrigerant injected into the evaporator coil. That's why it seems opposite from intuition. I had to re-watch that part of the video, until I realized that the bulb, and the temperature are both at the outlet of the evaporator, then it actually made sense to me.
@@aaronmouzin7258 You're right, if you measure right at the expansion valve. The bulb of the TEV and the measurement are taken at the OUTLET of the evaporator coil, AFTER the warm air has heated the volume of refrigerant. That's why, counter intuitively, less refrigerant results in more superheat. There just isn't the volume of refrigerant necessary to absorb the heat from all the warm air passing through the evaporator coil. If what you say is right, it's time to replace that air filter!
Just had a heat pump installed and have had the installer out 3x now with the A-coil completely frozen, saying it’s a bad expansion valve, I hear in this video how the smaller lines are “delicate”… Well, ours look like they just yarded the damn things out all haphazard, looks like total crap..,
I've heard of guys warming the bulb to see if the valve opens up I've done it myself especially if you're expecting possible moisture in the system but I've never heard of anybody icing a valve I suppose you could if you were just looking for action in the valve cuz I know the expansion valves can go full open but there really isn't a closed state the only ones that actually go closed are the EV valves
i think that must make schedule and record 1st revolution per 15 minutes or each half revolution per 10 minutes and type of revolution left or right and see the results if good or not to make it easy in case return it back.
Thank you very much for explain in theoretical way. I used to think it would be better for the video to be 50% long, after I complete it I think 25% would be more clear. I did gained from this video, yet just as other comments 100% practical video might be better. For example, how to adjust a R22 TxV for R410a or vice versa. And, TxV is used as reference measurement, what we can based on to do the adjustment? Like you want to calibrate a 2.5% pressure gauge clock you need a 1% gauge right?
My company keeps trying to use these thermal expansion valves on low temperature Chillers that we manufacture. They are anything but an constant superheat valve. The electronic expansion valve it's so much more Superior especially with variable heat loads. The problem I have is the electronic expansion valve controller wants to fault out if I run the suction pressure into a vacuum period or if I run my suction line temperature below - 59 degrees Fahrenheit. Then the controller wants to fault out and close the expansion valve completely. When I talk to an engineer at Sporlan he asked me how low do you want to go. I'm like negative 100 degrees Fahrenheit. He just laughed at me.
Will adjusting txv let me lower the temp? Coldest I can get so far on my car is 45F. And would like to drop it more. My txv has a spring adjustment. I also tried switching from r134a to r152a
What is the issue if low superheat at the outlet of evaporator coil and also low suction pressure for R22 system? Confirmed Evaporator coil is clean and supply fan at high speed. Suction pressure at 50 psi only with return of 80 F. Discharge 215 psi.
Lennox warranty is givin back out adjustable indoor txv when it comes to stock txvs ..and guess what they are coming out closed.so you might as well start the system with it wide open and close it til your gauges look good..now at wide open within the first 20 mins the compressor will start making out chattering noise
HVAC IS AMAZING! I LOVE HVAC! just what is HVAC? doesn't matter CAUSE I LOVE IT!!!!!!
Q
You mean HVACR, not HVAC.
R Jobs Matter!
Man, if I understand correctly, you are teaching HVAC students as a part of your activities. So, I wish I had a mentor like you years back when I was at the beginning of my way. You have a great talent to put the whole story short, clear and easy to follow. Your students are lucky to have such a great teacher.
Very informative. just saved my ass at a disaster of a job today. Got my superheat correct
Great video ,,for the technician out there ,,take a black marker and mark the bottom of the TXV before you start adjusting so you know where you started ,,make half turns ! Left or right so you can see where your sub cooling is going up or down..I wish On the videos you would show how it works
This video Presentation is very informative to all people working on AC Units around the Country. Thank You.
I really enjoyed this detailed presentation on the Expansion Valve!
This Video will go into my most valued folder as an accurate reference point!
Thank you much.
Awesome video. Glad i watched. Found a 5 year old R22 4 ton split A/C system with a closed txv. Flat sensing bulb. I weighed the charge in and my suction and head were low. Ambient temp in the lower 70's. Need to go back when i have a good ambient to check the superheat and sub cooling. Parker said the valve comes set @ 10 degrees superheat.
Excellent video Brian. One of the few viewed that explains a TXV in simple English.
Thank you. Very thorough. I appreciate all the "filler words"... they added the detail that I wanted to know.
Thank u sir....
Dear sir. You explained in theory its 50% knowledge for us. Better if show me. Practically its 100% exalent for us sir.
Great video.Thanks for imparting and sharing your expertise with us. A request could U do a video on selecting a TXV for a particular evaporator coil what parameters would I need to consider.
Definitely learned a lot from this video. Thank you
I go off manufactures specs txv’s coming preset from Factory. I think adjusting can make things worse, replace with new one better safe then sorry instead of tinkering with it and trying to get it dialed in. Week later your back on the roof and the comp is flooded.
It’s also important to note that superheat is pretty important to the compressor. It’s important to know what your superheat is before it reaches the condenser because if the superheat is perfect at the evaporator but too high at the condenser then that can create an issue.
I love all this fancy equipment now a days. I did refrigeration 40 years ago on 20 tonTurbo Ice Makers 12 plates 12 distributors on a txv and NEVER used a temp probe to do superheat.
Simple open txv till it just starts to flood suction, close it to bring frost line back to evaporator, DONE deal you are using all of the evap, and not flooding suction line.
And a txv with external equalizer tube that is attached to the suction line at the bulb
does just what I explained (it will kind of by pass the temp bulb) till the evap gets established.
Sounds similar to my first boss, he would go further by licking his finger and seeing if it would stick on the outlet of evap. He did this on freezer coils and ice machines.
Sounds interesting but how did you prevent slugging (liquid in suction line) when flooding?
Yup we use analog gauges n do what u said lol
this method I read many years ago in " Doolin's Bible". but that method was used for cap tubes with a critical charges not TXV's.
That's interesting then I work on turbos today I've got one that's running to 120 s and I got one that's running a hundred and fifty horse screw
Hi Ben Brian Great tutorial, I really like watching your studies and I wish I had the opportunity to study with you. Who knows, maybe one day it will come true. I have a professional question. I am a technician of industrial cooling systems. How do I know how to correctly measure subcool and superheat according to the seasons? Is it summer? Does it change? Because it's colder or hotter outside? And what is recommended to be in cold rooms at low temperatures? 4 degrees Celsius and minus 18 degrees Celsius Thank you very much appreciate it..
0:59 - The purpose of the thermostatic expansion valve is to maintain the correct amount of refrigerant in the evaporator coil for any change in load conditions by assuring a constant superheat at the exit of the coil. When the load conditions call for more refrigerant in the coil (such as during a hot pull-down when, say, the door of a walk-in is left open for an extended period), the rise in temperature at sensing bulb will push the valve further open.
12:34 - The number of degrees of superheat is directly proportional to the volume of vapor within the coil - the more vapor taking up space in the coil, the less room there will be for boiling refrigerant (and the less efficient the box will be). Just sayin’
just a little about dirt ,,,i ran into so many contractors about brazing with nitro ,,,,they say oh i never had problems or call back because i did not use nitro ,,,,,then it becomes an arguement ,,,,and i am talking about guys with years of experience ! ,,,its all about the money first , get my house cool for as low as you can ,,,lol i am old school i was a certified welder with over 30years experience when i decided to go to school for HVAC . every tech tries to impress the other LOL ,,,,,just saying this school is good stuff for all of us ,,,,i am retired but love to learn more
Nice video thanks! But 5 min would be enough. first half is water of time. I also want to know, whether R22 TxV can be adjusted to fit R410a
Very good explanation on adjustment. Best check airflow and superheat at evaporator. Also ^ TD . I have only adjusted valves in refrigeration units, walk-ins and freezer. Ole style Q body valves were much easier to adjust and maintain S.H. For the smart super techs, if you listen to Bryan Orr might learn a wealth of knowledge.
Did you do diagnostic on TXV in walk-in the same way that shown on the video? I am trying to understand, can I use this information for walk-in.
Clockwise, increase superheat, Counter clockwise decrease superheat. Just like a clock, numbers increase going clockwise.
Took this guy an hour to not say that.. thank you.. jeez...
@@Z-Ack spw turns 1/4 turn at a time then wait 20 or 30 minutes to stabalize. But you should not have to adjust TXV unless system is mixed matched in tonnage or some long line set. I am not an expert on this but I did stay at a Holiday Express last night.
Very good advice to ADVICE guys
I'm at a lost of what copeland wants for their semi-hermetic compressors. I know they say generally a minimum of 20 degrees but does that 20 degree apply to all applications or just A/C ? What about low temp refrigeration? or chillers? There's not much info on this. I noticed some applications run high superheat such as low temp and it makes me ponder if these are typical running conditons or should i go after my TXV and adjust it to drop superheat temp. I guess overall having superheat is better than not having any.
If the fins at that evaporator coil are really bad the txv would keepint the target super heat ?
Very informative. Thank you sir
Hi I have a 6 Ton carrier split unit with a "Piston" I would like to replace it with a Sporlan TXV (I have the TXV on hand) but I also want to add a suction line accumilator . What size range of the accumilator (in Liters) should I use . Thanks very much
Great demo, thanks! 👍👍
Good job, Brian.
Enjoyed the Podcast ! Works good to pass the time while doing the
dishes, also picking up a thing or two here & there. been doing
refrig . since 1981, also information on whats going on in the trade
sometimes. Thanks for making them.
Very accurate and thorough video.
If I reach the subcooling value to the exact number stated in the label of the condenser's unit charge value which is 10F but the superheat goes to 1 or zero.. should I adjust the TXV valve to increase the superheat value to normal levels??
Very good detail explanation thank u
Love your classes. Outside is subcool. Isn't it?
Will vacuum to 500 micron damage the pressure head of the TXV?
No. It's not part of the system. I assume you are talking about the power head.
Thanks Brian, question please, I always have hard times brazing these short necked TXVs, I cannot easily roll them well with a wet rag, I use a strong neutral flame to make it fast but, the rag tip gets burned carbonizing the joint and the valve over heats rapidly, any suggestions? Thanks
Excellent video, You will find most expansion valves are set real close for the proper super heat out of the evaporator. Many factors like laid over coil fins, wrong RPM motor or fan blade pitch can cause fake readings. My question is How much coffee did you drink before filming this:)
Without charging the gas, the pressure in the suction increases and the cooling decreases, why is this problem happening?
6 to 8 ° is extremely low . I’m looking for 15 to 20 degrees superheat at the compressor. I’m not sure why it would be so important to check evaporator superheat in air conditioning refrigeration yes but We are trying to make sure our compressor has good super heat and we’re not flooding the compressor …….. 15 to 20 degrees superheat at the compressor is what we’re looking for
If you have a system with multiple evaporators, you're gonna have to check superheat at the evaporator outlet.
so essentially when adjusting superheat setting your going CCW or CW facing the bottom of the valve at the stem not facing the power head?
You Stepped WAAAAY Outside of Explaining ANY TXV Action within the 3:00 minute mark for ANY HVAC TECH of 1-2 years ...........you are just speaking to Yourself at that point........KISS!
Thanks! Make sure to share your simplified video so I can watch and comment.
I'm not a HVAC tech and I enjoy the details. I have gauges and have charged 410 and 22 myself in years past. More knowledge is power. My local HVAC tech came to troubleshoot my Trane and he could not explain to me how to check the TXV. It was replaced once already by Trane and symptoms seem to indicate that it needs an adjustment.
Speak for yourself. Understanding how the components in the system work makes you better at troubleshooting. Never stop learning.
i have 65hp system -40C° ... How do I know the appropriate amount of refrigerant for this system?
Good explanation Bryan.
Thanks so much for sharing your knowledge. 👍👍👍👍👍👍
Can you adjust a r22 TXV enough to work on a 410a system?
Hey guys what s the best way to adjust 3 x TEV danfos valves
So it's fitted with manuprop MT 160 compressor and 3 evaporators
Thks Tony
Yes a CSV makes complete sense and not those other misleading confusing names
Can you not put a stainless steel pipe clamp around that bulb to mate it to a copper line? Or will the SS react with the copper?
I have used stainless worm clamps forever. Rule of thumb - clean and tight, never use cork tape or foam tape.
Problem with that is that metal is conductive and what you're trying to avoid is changing the temperature based on conditions other than the temperature of that copper. This is the reason we use cork tape, as it is a insulating material. Remember that the bulb reads temperature, and that the TXV converts that temperature into pressure and back. For proper operation and easier troubleshooting, avoid using a conductive material around the bulb.
ok i just learned this the hard way, 9:00 min in, i was working on a walk in and reading the temp/ psi at the condensing unit, so i think i bungled the super heat. i had i lot of bubbles inside the sight glass a more experienced technician said just add more 404a till the bibles stop and than just a bit more. i did. bit, but now i don't real know if its a leak or broken txv? i should have done a leak check but hind sight is 20/20 i guess.
ho to adjust at bat 12:00
I am an ectrician by trade but the ac at my house quit cooling. Its not cooling at all. The condensor I think came with the house and it was built in 1987. The inside unit was installed around 2000. Its a 3 ton ac unit 120 volts. It stopped cooling about a year ago and it quit working all at once. The compressor is running and I had a friend check the freon and he said it is low but not so low it should have quit working. I'm thinking it might be the TXV. I have airflow going thru the unit, its just not cold at all. Any idea's
is this a video about how the valve works or a troubleshooting video????
If you know one you can do the other, if not don’t feel bad, if it was easy anybody could do it !
Good stuff as always Brian!! 👍🏻👍🏻👍🏻
We have a freezer at my job place R404a and it start to freeze the suction line all the way too the compressor,could it be the txt?
No think air flow or your refrigerant is low.
If you have freezer temps it is normal to have a freezing suction line. The evap will have a temp of approximately -15 degrees. If your superheat is 10 degrees then the line temp will be -5 which will freeze the condensation. Check your superheat, if it is in the normal range then it is ok.
hey great video. what of expansion valve you using this video is it a gas charge sensing element or liquid cross charge.
So how do you determine what your superheat should be? With ac I understand it’s five or take 1 or 3 but on critical charge systems how do you know?
Always refer to the manual, if one is available.
What i am always wondering: Is such a TXV fast enough? How many seconds does it take between change of temperature of the refrigeration fluid behind the evaporator and change of temperature and pressure in the sensing-bulb? I guess, that can take half a minute or more.
Unless you have WILD load fluctuations, yes, these will respond more than fast enough.
Good information, good refresher. Boring from a video presentation viewpoint, watching a TXV be turned over and over for 19 minutes. I would expect that from an average Joe, not from a "School". But, still very good information. I got the "How" from this but still a little fuzzy on the "Why and When". Did you mention that adjusting the TXV is the LAST thing to do? And that the charge, clean condenser coil and evap coil, correct airflow through each should all be nailed down first? You may have, I just may have missed it. A have seen dudes just reef on that stem, many turns in one shot. You correctly advised against that. Good jjob overall, thanks.
Failure rate of tevs is fairly low. They can fail. But modern tev's are fairly reliable. They are more like to be destroyed by someone who doesn't know how to keep them cool while brazing.
Well explained thank you Sir
Thanks for your superb explanation. Very helpful and I'll probably refer to it again. :-)
Mine maintains superheat of 21 degrees with a sub cool of 12.8 degrees with manufactor specs call for 13 degrees for a temperature of 90 ambient, it's a 12 year old icp r22. :)
Whats super heat? Is it the unit heat has to 20 degrees above outside temp.
Will adjusting the TXV also also the ac to dehumidify the air? If so how?
no
@@mikemc8495 So I thought that a AC can dehumidify as well? Is so how?
@@mikemc8495 So what does the TXV do?
It meters the flow of refrigerant
@@JPE_DRAEB hey, when you lower the temperature of air the moisture is condensed into water leaving the air dryer
Great videos!
Will this work for a heat pump
whats the reason why having lot of refrigerantion oil at the filter drier.ty
Why do people say reducing superheat (smaller safety factor against liquid) uses more of the evaporator / is more energy efficient?
Well you dont want your evap coil being filled with liquid 80%-100% of the capacity. You want it to the point where in the middle of the coil its vapor (thats what you wanna feel to feel cool)..some people over charge a unit to the point where that vapor point happens at the suction line which at that point its past the blower motor cool air going back to the compressor and not your house instead of cooling you its cooling the copper lines itself ..its just like car you want your combustion to happen inside the engine not at the exhaust thats why you hear and see dumb high school kids now adays doing dumb mods to the cars that make it sound like gun shots thats combustion happening at the exhaust and not at the engine
Thank you, very educative .
You say adjusts a TXV to get correct super heat what about adjusting it for Sub cooling? I installed a Danfoss tr6 into a system that had a piston orifice and now I'm having trouble charging to 10 deg Sub Cool. I'm at 7-8 degs and cant get it any better. Oh and it not responding to charge because I've gone for low to over and still cant make the ideal S/C
for 404a if my suction is sweating like crazy can I choke the txv to raise the superheat to reduce the sweating?
This is great stuff. But I'm confused. I'm relatively new to the trade. How come when your dealing with a split system they tell you if you have a piston you charge for superheat but txv/tev it's subcooling you go off of? But the valve actually keeps a constant superheat? Sorry for my ignorance just want to better my understanding!
The superheat is controlled by the TXV, the subcooling is determined by your charge
So if TXV is icing up and the house temp doesn't go below 78 --- is that a clogged TXV? Thx in advance!
Not necessarily... the TEV causes a restriction, so condensation is normal. Frost is probably an indicator of high superheat. I.e. not enough refrigerant. Just my guess.
@@LemonDuc figuring out why it's low on refrigerant is the fun part! 😁
One thing you forgot to mention: column pressure. A system, where the evaporator unit is in the attic, or in the basement, creates a different pressure at the valve, than at the ground level condenser unit, the result of liquid in the high pressure line. Old units, with R-22 refrigerant will show bigger differences, then newer units, with R-410, or R-134.
What if my evaporator suction line is frozen.... on r410 ac heat pump split system, does it mean that superheat most likely too high?
No it means either your filter is dirty, indoor motor is bad, airflow restriction, or a freon leak. What's the pressures?
I just had my AC unit serviced and the guy refilled the refrigerant since it was completely empty. Now my AC unit is really struggling to pump cold air - i was thinking of giving this valve a half turn to allow more refrigerant through - is it possible it was reinstalled "too closed"?
If your system was empty it has a refrigerant leak. DONT touch the valve. If it's not keeping up it's probably losing refrigerant at a high rate.
I have r507 chiller operating at 1 to 4degC . What is reco. Superheat..I test it once, measure it in the evaporator, suct.temp is -1C then suction pressure is 50psi..according to chart 50psi is -10C . So my SH is 9deg.C..is this right?
I work for a Fluid Chillers inc. We shoot for 15 degrees Fahrenheit superheat, but mainly we don't want the compressor to ice up. Low-temperature evaporators are very susceptible the heat load supplied to them. And even though he calls it a constant superheat valve, they're anything but. As the load begins to drop so will the superheat unless you have an electronic expansion valve. In a low load situation a superheat of 10 degrees Fahrenheit is fine but then as the load increases you could have a super heat as high as 40 or even 100 degrees Fahrenheit depending on how hot your load is. We're on chillers from 68 degrees Fahrenheit setpoint all the way down to -80 degrees Fahrenheit setpoint. I'm a huge fan of electronic expansion valves the stepper motor on the valve is so much more Superior than your silly diaphragm valve
good information! Thank you for making videos!
My trane unit 410 subcool is 10 and the saturated evap coil temp is 50f is that normal? My old trane r22 evap sat is around 38 to 40
my succion is going into a vacuum opening my low pressure switch in about 30 secs.. I only have a txv and filter drier in my system.. can I say it's either or that's bad?
LEAK !
Leak?????lol
Xnlt explanation of a tev thank u..
Happy to help
thanx for the awesome vid
a question sir, the ac in my car, it is cold at idle but blows warm air when moving/revved. all the necessary things have been replaced with new ones ie cooling coil, condenser, expansion valve, filters. the only thing i havent done is adjusting the expansion valve
plus, the low side pressure increases when the engine is revved, can this be the source of my problem? tqvm
can a txv hunt with a slight undercharge? considering load, airflow and valve are sized properly.
The basic rule is:
Not enough superheat = not enough refrigerant.
Too much Superheat = too much refrigerant.
If a TXV hunts a lot check the bulb placement and how well it is attached to the suction line, mount your bulbs at 10 oclock or 2 oclock, never at 6 oclock.
Make sure bulb has full contact with the line, you may need to sand off any oxidation or grime that has built up on the copper before mounting a bulb.
Insulate the bulb with Cork Tape or Permatape after mounting.
exactly the opposite. Low on refrigerant = high superheat, High on refrigerant = low superheat
Not so fast ! I agree that low on refrigerant = high superheat The other part can vary. Why ? Mainly because we could run into restrictions for any number of reasons: bad or stuck TXV, clogged or partially clogged strainer, partially stuck pump down valve, restricted drier, etc. There is only one variable that I can promise. IF there is a bad restriction, and if the system is tight AND correctly charged, the liquid (refrigerant charge) will back up into the condensor because it can't get to the evaporator. When you take the pressure readings and temperature readings on suction and particularly liquid lines, the evidence will be far too much sub cooling on the condensed side (because the liquid is back up into the condenser side.) Try this one out: I once had a system that was only two years old but wasn't cooling correctly in 90's. I was told to change it out and replace it. As I recovered the refrigerant, I discovered that the unit had never had the accurator (for metering refrigerant) installed. It was running "hollow pipe". This was the fault of the installer.
@@repetemyname842 You would be exactly right, if you measure temperature right at the expansion valve. In this video, he's measuring temperature at the OUTLET of the evaporator, after the warm air has heated the volume of refrigerant injected into the evaporator coil. That's why it seems opposite from intuition. I had to re-watch that part of the video, until I realized that the bulb, and the temperature are both at the outlet of the evaporator, then it actually made sense to me.
@@aaronmouzin7258 You're right, if you measure right at the expansion valve. The bulb of the TEV and the measurement are taken at the OUTLET of the evaporator coil, AFTER the warm air has heated the volume of refrigerant. That's why, counter intuitively, less refrigerant results in more superheat. There just isn't the volume of refrigerant necessary to absorb the heat from all the warm air passing through the evaporator coil. If what you say is right, it's time to replace that air filter!
On the 3 x evopators the orifice is no 3 thks Tony
Thank you for your videos they are very instructive
It a dryer was installed. Would help in keep the txv free debris so it wouldnt get stuck.
great video, thanks 👍
Great Video. Thanks
Great video 🤙🏽
Increase superheat= lower suction pressure?
Suction pressure is determined by the compressor.
Great video ty
Just had a heat pump installed and have had the installer out 3x now with the A-coil completely frozen, saying it’s a bad expansion valve, I hear in this video how the smaller lines are “delicate”… Well, ours look like they just yarded the damn things out all haphazard, looks like total crap..,
How can we make it with EXV ?
How about testing the bulb with ice and warming the bulb
Yea, good idea.
I've heard of guys warming the bulb to see if the valve opens up I've done it myself especially if you're expecting possible moisture in the system but I've never heard of anybody icing a valve I suppose you could if you were just looking for action in the valve cuz I know the expansion valves can go full open but there really isn't a closed state the only ones that actually go closed are the EV valves
i think that must make schedule and record 1st revolution per 15 minutes or each half revolution per 10 minutes and type of revolution left or right and see the results if good or not to make it easy in case return it back.
Thank you very much for explain in theoretical way. I used to think it would be better for the video to be 50% long, after I complete it I think 25% would be more clear. I did gained from this video, yet just as other comments 100% practical video might be better. For example, how to adjust a R22 TxV for R410a or vice versa. And, TxV is used as reference measurement, what we can based on to do the adjustment? Like you want to calibrate a 2.5% pressure gauge clock you need a 1% gauge right?
Very useful
9:22 "just use some common sense"
And there we have the problem since the majority of the worlds ppl totally lack this.
My company keeps trying to use these thermal expansion valves on low temperature Chillers that we manufacture. They are anything but an constant superheat valve. The electronic expansion valve it's so much more Superior especially with variable heat loads. The problem I have is the electronic expansion valve controller wants to fault out if I run the suction pressure into a vacuum period or if I run my suction line temperature below - 59 degrees Fahrenheit. Then the controller wants to fault out and close the expansion valve completely. When I talk to an engineer at Sporlan he asked me how low do you want to go. I'm like negative 100 degrees Fahrenheit. He just laughed at me.
Will adjusting txv let me lower the temp? Coldest I can get so far on my car is 45F. And would like to drop it more. My txv has a spring adjustment. I also tried switching from r134a to r152a
What is the issue if low superheat at the outlet of evaporator coil and also low suction pressure for R22 system?
Confirmed Evaporator coil is clean and supply fan at high speed. Suction pressure at 50 psi only with return of 80 F.
Discharge 215 psi.
a tricky question for insiders. I think there is a restriction in suction line---kink somewhere, just a thought,an outsider
its a lack of airflow across the coil. ductwork is likely junk, undersized return.....
Can somebody tell what kind of tool set he is working the name brand?
Jermaine Sims Testo wireless probes. adjustable (crescent) wrench is a kobolt it looks like
Lennox warranty is givin back out adjustable indoor txv when it comes to stock txvs ..and guess what they are coming out closed.so you might as well start the system with it wide open and close it til your gauges look good..now at wide open within the first 20 mins the compressor will start making out chattering noise