Very well explained , I just finished my HVAC course from Lincoln tech and pretty much wasted my money so a lot of us rely on good tradesmen like you to really get a virtual hands on understanding . Thank you .
Should always check super heat just outside the evaporator 6 inches or so. Also you have a kinked liquid line just before inlet of TXV, could be causing a considerable pressure drop. Also change power head before adjusting valve, and if it has a screen on the inlet of the valve, check to see if it has any debris. Good Luck
That’s frosted all the way back to the compressor. You’ve either lowered the super heat more than you think, or you’ve overcharge the system. In this case it may be a good idea to look at the feeder lines coming off of the txv to the evap. One of them may have been restricted causing your high super heat., and one section of the evap frost free.
Thanks for the video. It had R408a according to writing in marker on condenser. A follow-up video/comment could explain that if the room is recovering temperature the suction/evaporating temperature is slightly high and will drop as the room temp lowers.
Why you have to adjust the txv if it was working properly before?looking at your suction pressure and considering that the evap coil have some ice i assume you have overcharged the system.Also you dont measure superheat without cleaning the ice of the evap coil first
Man, some of these guys are downright mean-spirited. It almost looked like one of the three circuits was restricted. It may be because that particular leg was a bit more restricted than the other two.... whatever. It was obvious the coil was starved in the middle. The charge was ok with a clear sight glass. Strap that thermistor to where it comes out the box as best you can, the closer to the evaporator, the better. The real problem is when the TXV was installed, someone failed to use a backing wrench and twisted the liquid line, you can clearly see the pinched liquid line just under the TXV. Fix that to restore refrigerant flow,..... check the strainer while your there. Good luck.
@@dnoorian I have a chiller room Bitzer compressor 15HP operating at 2 to 4 deg.C..the suction part of my compressor have a frost..then my evaporator coil at the side of evaporator have a thin frost. The system refrigerant is R507. I check the SH at the evaporator the actual suction temp is 50psi according to chart equivalent is -10C and measure the suction pipe temp the actual temp is -1C..computing the SH is 9deg C superheat. Is this right?
now let me pick you're brain i see the twisted liquid line but its 3/8 did you know that 3/8 is 10 times to big .... 1/4 would be able to flood this coil with in seconds...... have you seen a orifice before .. the opening did you know that the opening is than 90% covered ... ?? a twisted liquid line restricting slow moving liquid? i dont think so junior like i said that close to the txv and you are worried about proper refrigerant flow? when its about to enter a tiny opening ... come on dude
Should always take super heat at the evaporator but this probably isn't too far from the evap. I would have also put system through a quick defrost to clear the evaporator of frost before adjusting the superheat. Did you notice the line pinched going into the TXV? This may be what was restricting refrigerant maybe possibly. Thanks for sharing this with us.
This should be a video of what not to do. Don’t get me wrong he’s trying. Although, don’t make a video showing others how to correct issues when you’re taking shortcuts, and not resolving major issues. Just because it cools when you leave doesn’t mean it’s a great repair. Example: suction line so frosted the compressor is building frost.
Not trying to be negative. But there’s a lot left to be desired watching this with your diagnosis. Subcooling is pointless on units with a receiver. Superheat not measured where it should be. Etc..
Banana Crapshoot I enjoy inputs like yours: SC is 7-11 degrees regardless. The Refrigerant has to be cool and at a starting point for the expansion valve. SH should be measured at the bulb or exiting the evaporator and should be 5 degrees. FREEZER ~Evaporator temp: -18 to -21 SH: 5. Class 1 Refrig: BT - 8 deg box temp (BT): -10. SC: 7 to 11. Low pressure cut-out: 15 to 20 psig. High pressure cut-out: 350-400 psig. Head pressure:
Banana C. You said, Subcooling is pointless on units with a receiver = that means when a unit has receiver don't worry about the subcool !?! Do you know why the system needs subcool? ;) receiver is not a liquid/vapor separator, by the way, maybe you think that ''the receiver will only fill the liquid line with liquid refrigerant'' you are right, but on one side you forgot that refrigerant flash right in TXV, and liquid drops will start absorbing heat in distributors, not in coil section. because; no subcool. refrigerant can not absorb heat as soon it's 0° SC. Manufactures have subcooled specifications on their system, relationship with distributors length. If you want to look for more information about this, just go on parts manufactures and look for technical information.
I would’ve measured the superheat at the Evaporator and the thing that I didn’t like is when he measured superheat when the suction line is ice up . Not getting a correct reading.
Sys. gets moisture (bad purging/clean hoses), strainer inlet TXV get dirty, sight glass is full= drier should be good (if you have a doubt; can read delta temperature and pressure drop if possible)
How about using the reading of the pressure /temperature method at the evaporator outlet for that 6-8 deg F for R404a. Wouldn't that get a more accurate SH at the evap and prevent any possibility of floodback to compressor?
I have the same problem with R22 , machine in which I have use Danfoss TEV . It's work for 20 mins then frosting start at evaporator coil and suction pressure getting down to 35 psi then machine gets trip. Will it work for the above ...?
Hii sir , in walk freezer evaprator have frosting means gas charging proper or less ? Please advise suction pressure is 50psing discharge pressure 250 psing gas 404a cooling is not perfect..
Hello partner on duty! A got some kind of troubleshooting this type of problems... This time was a low ppressure in liquid line just afte filter drier (160psi) and quite good pressure in low side after evap n Comp rotalock (18-20psi) for a 404a walking in freezer meat storage. Txv and beyond still froozen. Sight glass is clear most the time then just flush ... I know is full, Maybe refull of refrigerante the entire system. Good both sides vents, cond-evap were washed. Help me, dont wanna loose this client😢
Thanks for the video and for the all the comments from posters below .. Myself being a Newbie in this field, Where did the target superheat of 17 come from as mentioned at 8:33.. If a TXV is a set and forget kind of device, was this particular TXV adjusted because it lost spring pressure ( age )? Was this a new install that never worked right?
How to know the correct superheat temp at the compressor? Is the value the same for every size of compressor or is the value based on the the type of refrigerant?
Thanks for sharing I have 404a walk in freezer inside doesn't go below 20 degrees f suction was 17psi... I made it 24 and left I called the guy he said still 20 degrees what would be problemsthatvi should check thanks
@@thomaspost5896 what is reason of ice frosting on evaporator coil. It's 404a freezer , suction pressure is 50 Discharge pressure is 250 psig , temperature not going below -15℃
You should always change the power head before adjusting a valve as they go weak and it is the only opening force of your txv. The system ran perfectly fine before, those valves don’t adjust themselves.
I was wondering the same thing. Wouldn't you tighten a txv to increase subcooling? If you have no subcooling how is an adjustment on the txv going to do anything. Bubbles in the sight glass and no subcooling would point to a leak I would think.
Mistakes friend,first defrost the evaporator,the valve allready is working low superheated and liquid is flooding in compresor.You "fixed it the opposite way",you destroyed it...haha
Your refrigerator is flooding back to your compressor. Your unit is over flooded. So what super heat are you checking there. You guys are confusing people.
@@michaelmcneffii1912 No, low charge can never flood back to the suction pipe outside. When unit is low on charge, it frosts from the metering device to the evaporator but can never return to the compressor. That's how you know undercharge. Overcharge frosts back through the suction line to the compressor. That's what is meant by flood back. Other factors apart from overcharge could be; 1 improperly adjusted Tev/Txv. 2. A larger outdoor unit against a smaller indoor. 3. When the fans are bad and can not supply enough air velocity to evaporate. 4. When the evaporator fins are blocked. 5. When the thermostat is back and can not check the temperature. These are mostly true on larger installations. In refrigerators, direct expansion undercharge can look like a flood back when it's not frost free evaporator, but you should tell the difference by your gauge and condenser temperature when you feel it. It does not require these experiments or trial and errors. Apart from these my boy, nothing else is there on flood back. Don't get yourself confused. Thanks for learning from me boy. Keep these information, you won't go wrong. Reach me on royalfidel@gmail.com.
Fidelis Obi correct, can clearly see the evap is frosted completely through to the header and back up, wrong move opening txv if anything requires closing
@@fidel03 this is a freezer you can still frost up and still have 100% vapor going back to the compressor. And how is he flooding the compressor when he has 35 degree superheat. Obviously not feeding enough. High superheat = starved evap. Low/no superheat = flooded evap
Very well explained , I just finished my HVAC course from Lincoln tech and pretty much wasted my money so a lot of us rely on good tradesmen like you to really get a virtual hands on understanding . Thank you .
why are those schools have to be WASTE OF MONEY all the time?
Should always check super heat just outside the evaporator 6 inches or so. Also you have a kinked liquid line just before inlet of TXV, could be causing a considerable pressure drop. Also change power head before adjusting valve, and if it has a screen on the inlet of the valve, check to see if it has any debris. Good Luck
That’s frosted all the way back to the compressor. You’ve either lowered the super heat more than you think, or you’ve overcharge the system. In this case it may be a good idea to look at the feeder lines coming off of the txv to the evap. One of them may have been restricted causing your high super heat., and one section of the evap frost free.
Yea, very likely that’s why only part of the evap coil was frozen in the beginning
Thanks for the video. It had R408a according to writing in marker on condenser. A follow-up video/comment could explain that if the room is recovering temperature the suction/evaporating temperature is slightly high and will drop as the room temp lowers.
Why you have to adjust the txv if it was working properly before?looking at your suction pressure and considering that the evap coil have some ice i assume you have overcharged the system.Also you dont measure superheat without cleaning the ice of the evap coil first
Thank you for the knowledge, success for "Dnoorian..." ... Pekalongan, Central Java, Indonesia attended
These videos are sweet please continue
Thanks. You can find more of these videos on my Instagram @dnoorian
How did you miss that pinched off liquid line at the bottom flare nut on the Txv valve?
Man, some of these guys are downright mean-spirited. It almost looked like one of the three circuits was restricted. It may be because that particular leg was a bit more restricted than the other two.... whatever.
It was obvious the coil was starved in the middle. The charge was ok with a clear sight glass. Strap that thermistor to where it comes out the box as best you can, the closer to the evaporator, the better. The real problem is when the TXV was installed, someone failed to use a backing wrench and twisted the liquid line, you can clearly see the pinched liquid line just under the TXV. Fix that to restore refrigerant flow,..... check the strainer while your there. Good luck.
hvac01453 thanks for your insight.
@@dnoorian I have a chiller room Bitzer compressor 15HP operating at 2 to 4 deg.C..the suction part of my compressor have a frost..then my evaporator coil at the side of evaporator have a thin frost. The system refrigerant is R507.
I check the SH at the evaporator the actual suction temp is 50psi according to chart equivalent is -10C and measure the suction pipe temp the actual temp is -1C..computing the SH is 9deg C superheat. Is this right?
Irving R. Lucas yes, sounds about right
now let me pick you're brain i see the twisted liquid line but its 3/8 did you know that 3/8 is 10 times to big .... 1/4 would be able to flood this coil with in seconds...... have you seen a orifice before .. the opening did you know that the opening is than 90% covered ... ?? a twisted liquid line restricting slow moving liquid? i dont think so junior like i said that close to the txv and you are worried about proper refrigerant flow? when its about to enter a tiny opening ... come on dude
You are a good man for sharing this. Thanks
Should always take super heat at the evaporator but this probably isn't too far from the evap. I would have also put system through a quick defrost to clear the evaporator of frost before adjusting the superheat. Did you notice the line pinched going into the TXV? This may be what was restricting refrigerant maybe possibly. Thanks for sharing this with us.
Yes I did notice that kink.... but it didn't seem to affect anything so I let it be. lol
B
This should be a video of what not to do. Don’t get me wrong he’s trying. Although, don’t make a video showing others how to correct issues when you’re taking shortcuts, and not resolving major issues. Just because it cools when you leave doesn’t mean it’s a great repair. Example: suction line so frosted the compressor is building frost.
Not trying to be negative. But there’s a lot left to be desired watching this with your diagnosis. Subcooling is pointless on units with a receiver. Superheat not measured where it should be. Etc..
Banana Crapshoot
I enjoy inputs like yours: SC is 7-11 degrees regardless. The Refrigerant has to be cool and at a starting point for the expansion valve. SH should be measured at the bulb or exiting the evaporator and should be 5 degrees. FREEZER
~Evaporator temp: -18 to -21
SH: 5.
Class 1 Refrig: BT - 8 deg
box temp (BT): -10.
SC: 7 to 11.
Low pressure cut-out: 15 to 20 psig.
High pressure cut-out: 350-400 psig.
Head pressure:
I agree, if this is like a pro, I'd hate to see a hack job.
@@thomaspost5896 Likewise to your inputs.
Banana C. You said, Subcooling is pointless on units with a receiver = that means when a unit has receiver don't worry about the subcool !?! Do you know why the system needs subcool? ;) receiver is not a liquid/vapor separator, by the way, maybe you think that ''the receiver will only fill the liquid line with liquid refrigerant'' you are right, but on one side you forgot that refrigerant flash right in TXV, and liquid drops will start absorbing heat in distributors, not in coil section. because; no subcool. refrigerant can not absorb heat as soon it's 0° SC. Manufactures have subcooled specifications on their system, relationship with distributors length. If you want to look for more information about this, just go on parts manufactures and look for technical information.
I would’ve measured the superheat at the Evaporator and the thing that I didn’t like is when he measured superheat when the suction line is ice up . Not getting a correct reading.
If a freezer & txv was operating properly before then it doesn't get cold. What causes a txv to need adjusting?
Sys. gets moisture (bad purging/clean hoses), strainer inlet TXV get dirty, sight glass is full= drier should be good (if you have a doubt; can read delta temperature and pressure drop if possible)
Bulb charge lost or loose attachement of bulb
Why did you not take Superheat at the evaporator. 6-8 degrees.
Its a habit for me to check superheat at the compressor, but checking the superheat at the evaporator was another option!
Dnoorian I check SH at compressor too. But evaporator is like6 degrees. Compressor, about 30.
@@rookierefrigeration4357 I would open that valve a bit more to lower the total superheat at the compressor.
How about using the reading of the pressure /temperature method at the evaporator outlet for that 6-8 deg F for R404a. Wouldn't that get a more accurate SH at the evap and prevent any possibility of floodback to compressor?
thanks from somalia bro
The delta across the evap coil ?
Liquid line before tx is twisted a bit. Can’t tell if enough to cause pressure drop.
I have the same problem with R22 , machine in which I have use Danfoss TEV . It's work for 20 mins then frosting start at evaporator coil and suction pressure getting down to 35 psi then machine gets trip.
Will it work for the above ...?
Hii sir , in walk freezer evaprator have frosting means gas charging proper or less ? Please advise suction pressure is 50psing discharge pressure 250 psing gas 404a cooling is not perfect..
Nice explanation brother
Hello partner on duty!
A got some kind of troubleshooting this type of problems...
This time was a low ppressure in liquid line just afte filter drier (160psi) and quite good pressure in low side after evap n Comp rotalock (18-20psi) for a 404a walking in freezer meat storage.
Txv and beyond still froozen.
Sight glass is clear most the time then just flush ... I know is full, Maybe refull of refrigerante the entire system.
Good both sides vents, cond-evap were washed.
Help me, dont wanna loose this client😢
There's no label about Oz or Kg to charge the Unit :/
Thanks for the video and for the all the comments from posters below .. Myself being a Newbie in this field, Where did the target superheat of 17 come from as mentioned at 8:33.. If a TXV is a set and forget kind of device, was this particular TXV adjusted because it lost spring pressure ( age )? Was this a new install that never worked right?
the reason for 17 is because its 10 degrees superheat at the compressor and 7 degrees superheat at the TXV. So, 7+ 10 = 17.
How to know the correct superheat temp at the compressor? Is the value the same for every size of compressor or is the value based on the the type of refrigerant?
@@ericdayo26 u read plate on each coil and comp
@@dnoorian 17K SH is very high at the compressor. Should be max 10k for better cooling of the windings of the compressor and the longevity of it.
Thanks for sharing I have 404a walk in freezer inside doesn't go below 20 degrees f suction was 17psi... I made it 24 and left I called the guy he said still 20 degrees what would be problemsthatvi should check thanks
Mr Adam
FREEZER
~Evaporator temp: -18 to -21
SH: 5.
Class 1 Refrigerant: BT - 8 deg
box temp (BT): -10.
SC: 7 to 11.
~Low pressure cut-out: 15 to 20 psig.
~High pressure cut-out: 350-400 psig.
head pressure: 285 psig.
Suction pressure: 17 psig.
Refrigerant: R404a
Courtnethegreat@gmail.com
Thomas Post good information;,,,,can have walk cooler information please. ,,,
@@thomaspost5896 what is reason of ice frosting on evaporator coil.
It's 404a freezer , suction pressure is 50 Discharge pressure is 250 psig , temperature not going below -15℃
What type freon u was used? What is standart superheat range.?
R404. Standard is 8-10 degrees
Standard is 2-5 for a freezer. Cooler 6-12
Its called refrigerant, not Freon. Freon is a trade name.
@@MrDeviousdom I was about to say the same thing... noobs.
If in multidoor cooler the temt of three unites is different how to increase the temp in one section if it is too low.
Individual thermostat that controls a solenoid or EPR valve in each evap circuit.
You should always change the power head before adjusting a valve as they go weak and it is the only opening force of your txv. The system ran perfectly fine before, those valves don’t adjust themselves.
Wow very nice.Good job
Where is your BEARD NET? That's a GMP VIOLATION.
Expansión valve is wide open
I do not want you working where I do. No subcooling but your solution is to adjust the txv? Wrong.
I was wondering the same thing. Wouldn't you tighten a txv to increase subcooling? If you have no subcooling how is an adjustment on the txv going to do anything. Bubbles in the sight glass and no subcooling would point to a leak I would think.
Hello good afternoon all my people
Nandor is that you?
Walk in freezer has low cooling
Mistakes friend,first defrost the evaporator,the valve allready is working low superheated and liquid is flooding in compresor.You "fixed it the opposite way",you destroyed it...haha
Your refrigerator is flooding back to your compressor. Your unit is over flooded. So what super heat are you checking there. You guys are confusing people.
Fidelis Obi Low charge will do the same thing
@@michaelmcneffii1912 No, low charge can never flood back to the suction pipe outside. When unit is low on charge, it frosts from the metering device to the evaporator but can never return to the compressor. That's how you know undercharge. Overcharge frosts back through the suction line to the compressor. That's what is meant by flood back. Other factors apart from overcharge could be; 1 improperly adjusted Tev/Txv. 2. A larger outdoor unit against a smaller indoor. 3. When the fans are bad and can not supply enough air velocity to evaporate. 4. When the evaporator fins are blocked. 5. When the thermostat is back and can not check the temperature. These are mostly true on larger installations. In refrigerators, direct expansion undercharge can look like a flood back when it's not frost free evaporator, but you should tell the difference by your gauge and condenser temperature when you feel it. It does not require these experiments or trial and errors. Apart from these my boy, nothing else is there on flood back. Don't get yourself confused. Thanks for learning from me boy. Keep these information, you won't go wrong. Reach me on royalfidel@gmail.com.
Fidelis Obi correct, can clearly see the evap is frosted completely through to the header and back up, wrong move opening txv if anything requires closing
@@fidel03 this is a freezer you can still frost up and still have 100% vapor going back to the compressor. And how is he flooding the compressor when he has 35 degree superheat. Obviously not feeding enough. High superheat = starved evap. Low/no superheat = flooded evap
@@jwoods1742 why would you close it? Evap is already starving of refrigerant
Ty
The compressor is too small The CF nine compressor is too small. You need a Zf9 The CF9 compressors are junk
thanks
Hair net, but no beard net? :)
hope you weren't the installer?
Alway check sight glass
Show the txv
nice
Hernandez Jeffrey Lee Margaret Wilson Joseph
Hi could you contact me ive got some ideas and tips
I am indian you speak in hindi i no understand to english also I am ac tecnicion
😂😂😂