Ty great video!!!🦸♂️ keep posting, How to properly do the procedures! Very important. There is not many people who does it correctly, and less people who can teach you! And less people who can make you understand a procedure, You are a great teacher!!!👍
Thanks so much, best explanation I’ve found. I didn’t understand the compressor valves would keep it captive as I’m working on refrigeration with just one king valve. Still new to HVAC
Hi Ty Love this tutorial & all yours Actually Thank you Ive learned a Ton ....27 + yrs in & learnt with no actual formal school but 5/6 great mentors to teach , lots of books & videos constantly .daily ..started out with trim & sets was my 1 st Job 3/4 years new construction then retrofits ..wired & fired then all .with help my mentor ... then service & then full installs last both resd & mid sized 30 ton usually & under but maybe 1- 10 systems installed per building commercial jobs my favorite ....So to me anyways one of the best ways to learn try to learn This great Trade .no formal school ...& always learning something new the new stuff happening dailuy it seems & also to relearn the old everyday stuff also ..Just wow what I just learned on ..a basic pump down & all its particulars & or must dos or best practices .....i do most all as per some differences ..But bottom line IS : to make the end game turn out as Hopped & carefully planned out & quoted the customer ..hopefully Not to many Surprises .along the way .thanks Again ...Please keep ur Great tutorials coming & we ALL Will .....keep watching & learning ..tks million of I had it !!!
Ty most technician don’t care for releasing refrigerant in the air while the global warming increase fast any way I’m really concerned for you’re teaching. Have a good weekend.💐
I was trying to do a pump down today. But around 2 or 3 seconds into the pump down the compressor went off. I tried again and same result. There are no low or high pressure sensors on the copper pipes. Great video. Thanks
@@love2hvac I am an appliance repair technician. 😎….I learned that trade from my father. ( as well as the occasional manufacturers class) like you, I was driven by my curiosity. Much of the basic electrical concepts are the same. I don’t have time to go to a formal school. I am learning OJT , and from books, and your channel. Thanks again ….I really appreciate the education.
Ty, thanks for all you do. I’m a wet heat guy ( ie boilers) working in a supply house. We are pushing into the HVAC market, and with your help ( and some other very good channels here) I’ve been able to learn enough to pretend to be mildly competent. That’s saying a lot considering how dense I am!
Some units have a high side pressure cutout switch AND a low side pressure cutout switch that will open the contactor if either trips. Don't get too surprised if your compressor stops at about 55 psig low side pressure. Shut off breaker power and be ready to shut down the low side service port. Microchannel condenser units often have a high side pressure cutout switch because they know it cannot take a pump down.
Hi Ty. Great video. Thanks. Could you advise on the following? recently I saw York “tombstone” condenser. I have no idea how old it is, maybe 30-40 years. It is running fine. But the interesting thing liquid and suction lines are tied together and insulated together (~ 20-25 feet) Do you know what the logic is behind insulating them together (same thing in domestic refrigerators)?
They where using the heat from the liquid line to ensure all the saturated liquid was boiled away to a vapor in the suction side increasing superheat. Also cooling the liquid line that increased subcooling that reduced flash gas. There is some arguments. If you reduce flash gas you end up with more liquid in the evaporator, so you get less superheat and closer to saturation on the suction side. So that becomes a wash. I am familiar with the York toumbstone but I dont know that I've seen an entire line set like that.
That “funny noise” in the demo is the floating seal preventing pumping into vacuum I’m pretty sure. 40psig is where I’ve found it normally starts. I’m not sure that’s what it actually is though, but I’m pretty sure it is indeed the floating seal.
Yes sir, Once the compression ratio exceeds 11:1 the floating seal releases meaning it's no longer a down force pushing the top scroll set down on the bottom scroll set . The rattling is the top scroll chattering against the bottom because the floating seal is no longer pushing it down to make the scroll set seal.
It allows the compressor to get up and running. When you start the compressor with a closed valve it builds pressure at at the age time the compressor is trying to get up to speed. The locked rotator amps are hard on a compressor and a lot of heat in generated in the winding at startup Adding immediate high pressure to that is not only hard on the compressor but it can also lead to internal thermal overload tripping. The combination of John pressure, high heat of compression and start up heat /amps is a lot to ask for.
Hello .A lot of outside unit got that third pipe or third valve in the midle of hight presure and lov presure valve .Can you explain what they are ? thanks
Hey @Ty Branaman I'm working on my associates in HVAC/R do you think it's worth getting a bachelor's in HVAC/R engineering technology or should I transition to mechanical engineering.
is it possible to perform a pump down on a heat pump in heat mode? I have an indoor TXV that is obstructed only in AC mode, but works (bypass) in heat mode. seems to me that pump down in Heat mode would capture all the refrigerant in the outdoor coil, where in AC mode it will leave refrigerant in the liquid line (because of the TXV obstruction) between the compressor and the TXV.
For anyone who has this same question, I'm planning to use my manifold gauges to pull the liquid line over to the suction line, effectively pulling all the refrigerant into the condenser.
For what your trying to accomplish, you need to do it in AC mode. Close the liquid valve and throttle the refregerant across the manifold to the suction line side. Untill the refregerant up pulled out of both lines Shut the compressor off and close the suction valve then your refrigerant will be stored in the condensor. In heating mode it's called a pump up. When you close the liquid valve the refregerant is backed from the liquid valve, to the metering device and the refregerant is stored in the indoor coil. Then you close the valves and you can work on the outdoor unit after recovering what is left. A pump up will not work if your having to work on the indoor metering device. Even with moving the hoses like you talk about will be a problem. In heating mode the compressor discharge is connected to the suction line. #1 there is not enough volume of space so store the refregerant in that distance. #2 it would be in vapor form as it has not yet gone threw a coil.
I'm sorry but i have to correct you, incresed arcing in a vaccuum compared to in a refrigerant happens only in very specific circumstances and is not a given. I would say refrigeration compressors are designed to operate within a certain range of operating conditions. Operating a refrigeration compressor with a negative suction line pressure, which means the pressure at the suction inlet of the compressor is lower than the recommended minimum operating pressure, can cause several issues such as: 1. Reduced compressor efficiency: A compressor is designed to compress a refrigerant gas from low to high pressure. When the suction line pressure drops below the recommended minimum, the compressor has to work harder to maintain the required flow rate and discharge pressure. This increased workload reduces the efficiency of the compressor, leading to increased energy consumption. 2. Loss of lubrication: The compressor relies on the refrigerant gas to provide lubrication to the moving parts. When the suction pressure drops below the recommended minimum, the amount of refrigerant gas entering the compressor is reduced, leading to inadequate lubrication. This can cause premature wear of the compressor's moving parts, leading to compressor failure.
An engineer for Copeland scroll compressor told me they had arcing at the Fusite connectors resulting in terminal blowout on scroll compressors. Copeland specifically states in several Application engineering bullitens related to the z line scroll not to use a megohmeter while under a vacuum. "Under no circumstances should the hipot test be performed while the compressor is under a vacuum." I was told by the compressor engineers this was because of arcing. None of the engineers or technical data I have read includes vacuum breakers. However Copland scroll uses a floating seal for protection. On high temperature air conditioning applications the seal opens above 11:1 well before the compressor ever gets to a vacuum. Refrigerating the floating seal does not open until it's great we then 26:1 but the compressor is designed much differently. I 100% agree the compressor should remain in the operating envelope at all times. None of the scroll compressors for high temperature air conditioning are designed to operate in a vacuum. With refrigeration the compressor should remain in the operating window even in automatic pump down. There are very few applications and refrigerant combinations that allow specific scrolls to operate in a slight vacuum. Those compressors are built specifically to operate in that window and I will cover that when I get to the refrigeration portion of the video series.
@@love2hvac Thank you for sharing your insights on Copeland's scroll compressors and the possibility of arcing in vacuum conditions. While the chances of arcing occurring in a winding can be affected by several factors, it is generally true that a vacuum provides better electrical insulation due to its low dielectric constant. However, in certain situations, the presence of a refrigerant gas may provide better insulation compared to a vacuum. It is important to note that the use of hipot tests, which apply a higher voltage than normal line voltage, can stress insulation and increase the risk of electrical breakdown and arcing. However, this does not necessarily mean that arcing will occur during a vacuum pumpdown at normal line voltage in a refrigerant. In the case of winding arcing in a refrigerant compressor, the breakdown voltage of a vacuum or low-pressure gas like for example R410a can decrease significantly due to the presence of free electrons and ions produced by the arcing. To maintain adequate electrical insulation, a higher pressure gas with a higher dielectric strength may be necessary. Although a vacuum is generally considered a better insulator than R410a due to its low dielectric constant, at very low pressures, the remaining gas in the vacuum chamber may not have a low enough dielectric constant to provide sufficient insulation. In such cases, introducing a gas like R410a could help to increase the dielectric strength and provide better electrical insulation. However, in most practical electrical insulation applications, a vacuum is still considered the better insulator because it has the lowest dielectric constant of any material, making it highly resistant to the flow of electrical charges. This is why vacuum breakers are commonly used in high-voltage power industries to interrupt the flow of current and prevent arcing.
@@gregdekkers2667 I'm not a scientist so I can't answer for sure. I was under the impression that electrons themselves move slower in a vacuum but the electromagnetic waves move faster in a vacuum up to 90% of the speed of light. I think Vacuum arc plays an important role here as even at low voltage you can have a a high amerage arc. While AFCI breakers are available they don't work well in HVAC as the arc of the contacts themselves making contact cause nucesance trips. Take a look at the Fusite plug of a compressor. Theterminals themselves are not insulated. In a vacuum this could be a prime condition for arc that explains why the Copeland engineers had the Fusite blow out. They said it was so violent, part of it stuck in the wall on the opposite side. I do appreciate and respect the conversation even though we don't completely agree. For reference "A vacuum arc can arise when the surfaces of metal electrodes in contact with a good vacuum begin to emit electrons either through heating (thermionic emission) or in an electric field that is sufficient to cause field electron emission. Once initiated, a vacuum arc can persist, since the freed particles gain kinetic energy from the electric field, heating the metal surfaces through high-speed particle collisions. This process can create an incandescent cathode spot, which frees more particles, thereby sustaining the arc. At sufficiently high currents an incandescent anode spot may also be formed. Electric discharge in vacuum is important for certain types of vacuum tubes and for high-voltage vacuum switches. "
@@love2hvac It's truly captivating. I must say, you've taught me something new and had me pondering it for half a day. I confess that I was mistaken in believing that a vacuum is always the superior insulator. It appears that the engineers at Copeland identified a specific case where this does not hold true, which I cannot dispute. (even though I initially did) The insulating properties of a vacuum are not perfect, and under certain conditions, such as in the presence of strong electric fields or charged particles, electrical breakdown can still occur. These cases are often specific and less common than the electrical breakdown in air or other materials. "As you reduce the air pressure, the mean free path of electrons (the average distance an electron can travel between collisions with air molecules) increases. Initially, this may lead to an increase in the dielectric strength of air. However, as you continue to lower the pressure, the dielectric strength may start to decrease, making it easier for electrical breakdown to occur. This behavior is nonlinear and complex, influenced by factors like the electrode configuration and the specific gas mixture involved. In summary, the dielectric breakdown of air is not a linear process when transitioning from atmospheric pressure to a vacuum, as it is influenced by various factors and exhibits a complex relationship with pressure."
Hello Ty, can you explain how to perform pump down on ductless system when temperature in the room is lower than it is possible to set on controller? How to force compressor to start if there is no contactor? Thank you for the answer.
I have not seen it first at but the people at the Copland factory told me it blows the fuseite plug completely out and tuck across the room. They lost specifics about not running the compressor in a vacuum because arcing is a big issue.
It's nonsense. We make vacuum breakers for a reason, to prevent arcing, so windings arcing in a vacuum is unlikely. Here are some reasons not to run in a vacuum: Refrigeration compressors are designed to operate within a certain range of operating conditions. Operating a refrigeration compressor with a negative suction line pressure, which means the pressure at the suction inlet of the compressor is lower than the recommended minimum operating pressure, can cause several issues such as: 1. Reduced compressor efficiency: A compressor is designed to compress a refrigerant gas from low to high pressure. When the suction line pressure drops below the recommended minimum, the compressor has to work harder to maintain the required flow rate and discharge pressure. This increased workload reduces the efficiency of the compressor, leading to increased energy consumption. 2. Loss of lubrication: The compressor relies on the refrigerant gas to provide lubrication to the moving parts. When the suction pressure drops below the recommended minimum, the amount of refrigerant gas entering the compressor is reduced, leading to inadequate lubrication. This can cause premature wear of the compressor's moving parts, leading to compressor failure.
When you need to pull and clean the evaporator, replace a metering device, and replace a filter drier. You can pump it down instead of recovering ALL the refrigerant. It's faster and less chance of contamination.
Thank for sharing the knowledge. Are all Refrigeration and Air conditioning units designed to pump down the refrigerant or is there any exception? Small refrigeration units that do not have accumulator and large condensing unit are suitable for pump down or not?
there is always exceptions. They vary greatly and it depends on the engineer who designed what they are trying to accomplish and the cost factor always plays a part.
The service valve is closed, the pressure between the compressor threw condensor to the valve will go up. There service port is after the valve even though it's on the same component. The compressor is pulling in refrigerant. So the compressor sucks in refregerant from the suction line, evaporator, metering device and liquid line to the valve. So the high side pressure on the liquid line drops because the liquid valve is closed and the compressor sucks it in.
@@love2hvac It should be less than this. No? This is the amount of refrigerant that would be in the system if it was operating normally. But you've pumped it down to like 10 psi.
I would not. The goodman filter drier is before the valve. If you pump it down, how would you change the filter drier. Some people pump if down and put a new filter drier outside. They leave the old one and. The old one becomes a restriction and damages the compressor.
Can anyone answer this? I have an evcon residential unit, was just installed a few months ago and was very quite. Now, when it kicks on, there is a loud buzzing noise. I felt around it a bit and nothing on the outside cage is rattling, nothing caught in the fan. Weird.
My neighbors heat pump makes one heck of a racket (buzzing noise) on compressor startup, much more than mine by at least 10x. I don't have a hard start kit for my compressor, maybe his does or it's just noisy, not sure...
Never heard arcing in vacuum. There is special class high voltage switches where switching contacts are in vaccum. Agree that can be dammaged but arcing in not a reason for sure.
Copland scroll manual page 18 at the bottom few lines climate.emerson.com/documents/copeland-scroll-compressors-for-refrigeration-zs09kae-zs11kae-zs13kae-application-guidelines-en-gb-4214008.pdf
@@love2hvac Hope you are not using silicone as a vacuum sealant as this guy. Video is joke. Beside that he is using neon transformer that produces tens of tousands volts. Much more than 208 or 460 that regular compressor runs.
@@aleksandarvasilevski7410 do you have any resources to share to back your claim? I'm always willing to lean but everything I find says scroll compressors are at high risk of arcing damage in a vacuum. Copland compressors have much better resources for testing this than I do and I dont have anything to show otherwise.
Don't ever stop making videos man.
Ty great video!!!🦸♂️ keep posting, How to properly do the procedures! Very important. There is not many people who does it correctly, and less people who can teach you! And less people who can make you understand a procedure, You are a great teacher!!!👍
Thanks so much, best explanation I’ve found. I didn’t understand the compressor valves would keep it captive as I’m working on refrigeration with just one king valve. Still new to HVAC
Hi Ty Love this tutorial & all yours Actually Thank you Ive learned a Ton ....27 + yrs in & learnt with no actual formal school but 5/6 great mentors to teach , lots of books & videos constantly .daily ..started out with trim & sets was my 1 st Job 3/4 years new construction then retrofits ..wired & fired then all .with help my mentor ... then service & then full installs last both resd & mid sized 30 ton usually & under but maybe 1- 10 systems installed per building commercial jobs my favorite ....So to me anyways one of the best ways to learn try to learn This great Trade .no formal school ...& always learning something new the new stuff happening dailuy it seems & also to relearn the old everyday stuff also ..Just wow what I just learned on ..a basic pump down & all its particulars & or must dos or best practices .....i do most all as per some differences ..But bottom line IS : to make the end game turn out as Hopped & carefully planned out & quoted the customer ..hopefully Not to many Surprises .along the way .thanks Again ...Please keep ur Great tutorials coming & we ALL Will .....keep watching & learning ..tks million of I had it !!!
Ty most technician don’t care for releasing refrigerant in the air while the global warming increase fast any way I’m really concerned for you’re teaching. Have a good weekend.💐
I was trying to do a pump down today. But around 2 or 3 seconds into the pump down the compressor went off. I tried again and same result. There are no low or high pressure sensors on the copper pipes. Great video. Thanks
scrolls have an floating seal that will open when the suction pressure gets too low
Thanks , your an awesome teacher ….I’m learning this on my own , coming from. another trade ….I really appreciate your channel.
Thank you I appreciate that.
If your motivated you can learn just as much and more on your own. What is your other trade?
@@love2hvac I am an appliance repair technician. 😎….I learned that trade from my father. ( as well as the occasional manufacturers class) like you, I was driven by my curiosity. Much of the basic electrical concepts are the same. I don’t have time to go to a formal school. I am learning OJT , and from books, and your channel. Thanks again ….I really appreciate the education.
Ty, thanks for all you do. I’m a wet heat guy ( ie boilers) working in a supply house. We are pushing into the HVAC market, and with your help ( and some other very good channels here) I’ve been able to learn enough to pretend to be mildly competent. That’s saying a lot considering how dense I am!
Awesome video gotta pull my evap coil and clean this weekend. Needed a refresh. Thanks.
Thank you for this detailed explanation and showing it live.
Some units have a high side pressure cutout switch AND a low side pressure cutout switch that will open the contactor if either trips. Don't get too surprised if your compressor stops at about 55 psig low side pressure. Shut off breaker power and be ready to shut down the low side service port.
Microchannel condenser units often have a high side pressure cutout switch because they know it cannot take a pump down.
Excellent detail, thank you!
Thank you for the update.
Hi Ty. Great video. Thanks. Could you advise on the following? recently I saw York “tombstone” condenser. I have no idea how old it is, maybe 30-40 years. It is running fine. But the interesting thing liquid and suction lines are tied together and insulated together (~ 20-25 feet) Do you know what the logic is behind insulating them together (same thing in domestic refrigerators)?
They where using the heat from the liquid line to ensure all the saturated liquid was boiled away to a vapor in the suction side increasing superheat. Also cooling the liquid line that increased subcooling that reduced flash gas.
There is some arguments.
If you reduce flash gas you end up with more liquid in the evaporator, so you get less superheat and closer to saturation on the suction side.
So that becomes a wash.
I am familiar with the York toumbstone but I dont know that I've seen an entire line set like that.
You are the best 💪
Isn’t the floating seal in resi scrolls designed to fall back down and start clinking to prevent pumping down into vacuum?
That “funny noise” in the demo is the floating seal preventing pumping into vacuum I’m pretty sure. 40psig is where I’ve found it normally starts. I’m not sure that’s what it actually is though, but I’m pretty sure it is indeed the floating seal.
Yes sir,
Once the compression ratio exceeds 11:1 the floating seal releases meaning it's no longer a down force pushing the top scroll set down on the bottom scroll set . The rattling is the top scroll chattering against the bottom because the floating seal is no longer pushing it down to make the scroll set seal.
@@love2hvac Interesting. Thank you so much!
6:28 - What is the approximate quantity of refrigerant left in a 55ft line set after pumping down to ~15#?
10:23 - Wow! That was _fast!_
great video thanks Ty
Why does the unit have to be running for you to close the liquid line service port? Why not close it then run the system. Is there a Difference?
It allows the compressor to get up and running. When you start the compressor with a closed valve it builds pressure at at the age time the compressor is trying to get up to speed. The locked rotator amps are hard on a compressor and a lot of heat in generated in the winding at startup
Adding immediate high pressure to that is not only hard on the compressor but it can also lead to internal thermal overload tripping. The combination of John pressure, high heat of compression and start up heat /amps is a lot to ask for.
Hello .A lot of outside unit got that third pipe or third valve in the midle of hight presure and lov presure valve .Can you explain what they are ? thanks
If the filter dryer is between the service valve and condenser/compressor is that side of the system technically not open ??
Hey @Ty Branaman I'm working on my associates in HVAC/R do you think it's worth getting a bachelor's in HVAC/R engineering technology or should I transition to mechanical engineering.
Oh that's a great question. You can't go wrong with either path. That is a choice for you alone.
Hi sir,tq for great video ❤️..Can you do live video do pump down using liquid reciever king valve ?
I can, it will be a little bit though.
thanks Ty
Great video, how do you recommend pulling refrigerant out of unit if drier downstream of the service valve?
Recover it
Is that low voltage run inside of 3/8 copper if so I love it
Yes it's an old school way of protecting the low voltage. Flared at both ends to prevent cutting the wire. Liquid tight conduits is still the best.
is it possible to perform a pump down on a heat pump in heat mode? I have an indoor TXV that is obstructed only in AC mode, but works (bypass) in heat mode. seems to me that pump down in Heat mode would capture all the refrigerant in the outdoor coil, where in AC mode it will leave refrigerant in the liquid line (because of the TXV obstruction) between the compressor and the TXV.
For anyone who has this same question, I'm planning to use my manifold gauges to pull the liquid line over to the suction line, effectively pulling all the refrigerant into the condenser.
For what your trying to accomplish, you need to do it in AC mode.
Close the liquid valve and throttle the refregerant across the manifold to the suction line side. Untill the refregerant up pulled out of both lines
Shut the compressor off and close the suction valve then your refrigerant will be stored in the condensor.
In heating mode it's called a pump up. When you close the liquid valve the refregerant is backed from the liquid valve, to the metering device and the refregerant is stored in the indoor coil. Then you close the valves and you can work on the outdoor unit after recovering what is left.
A pump up will not work if your having to work on the indoor metering device.
Even with moving the hoses like you talk about will be a problem.
In heating mode the compressor discharge is connected to the suction line.
#1 there is not enough volume of space so store the refregerant in that distance.
#2 it would be in vapor form as it has not yet gone threw a coil.
10:57 shup up an take my money....I need that
I'm sorry but i have to correct you, incresed arcing in a vaccuum compared to in a refrigerant happens only in very specific circumstances and is not a given.
I would say refrigeration compressors are designed to operate within a certain range of operating conditions. Operating a refrigeration compressor with a negative suction line pressure, which means the pressure at the suction inlet of the compressor is lower than the recommended minimum operating pressure, can cause several issues such as:
1. Reduced compressor efficiency: A compressor is designed to compress a refrigerant gas from low to high pressure. When the suction line pressure drops below the recommended minimum, the compressor has to work harder to maintain the required flow rate and discharge pressure. This increased workload reduces the efficiency of the compressor, leading to increased energy consumption.
2. Loss of lubrication: The compressor relies on the refrigerant gas to provide lubrication to the moving parts. When the suction pressure drops below the recommended minimum, the amount of refrigerant gas entering the compressor is reduced, leading to inadequate lubrication. This can cause premature wear of the compressor's moving parts, leading to compressor failure.
An engineer for Copeland scroll compressor told me they had arcing at the Fusite connectors resulting in terminal blowout on scroll compressors.
Copeland specifically states in several Application engineering bullitens related to the z line scroll not to use a megohmeter while under a vacuum.
"Under no circumstances should the hipot test be performed while the compressor is under a vacuum." I was told by the compressor engineers this was because of arcing.
None of the engineers or technical data I have read includes vacuum breakers.
However Copland scroll uses a floating seal for protection. On high temperature air conditioning applications the seal opens above 11:1 well before the compressor ever gets to a vacuum.
Refrigerating the floating seal does not open until it's great we then 26:1 but the compressor is designed much differently.
I 100% agree the compressor should remain in the operating envelope at all times.
None of the scroll compressors for high temperature air conditioning are designed to operate in a vacuum.
With refrigeration the compressor should remain in the operating window even in automatic pump down. There are very few applications and refrigerant combinations that allow specific scrolls to operate in a slight vacuum. Those compressors are built specifically to operate in that window and I will cover that when I get to the refrigeration portion of the video series.
@@love2hvac Thank you for sharing your insights on Copeland's scroll compressors and the possibility of arcing in vacuum conditions. While the chances of arcing occurring in a winding can be affected by several factors, it is generally true that a vacuum provides better electrical insulation due to its low dielectric constant. However, in certain situations, the presence of a refrigerant gas may provide better insulation compared to a vacuum.
It is important to note that the use of hipot tests, which apply a higher voltage than normal line voltage, can stress insulation and increase the risk of electrical breakdown and arcing. However, this does not necessarily mean that arcing will occur during a vacuum pumpdown at normal line voltage in a refrigerant.
In the case of winding arcing in a refrigerant compressor, the breakdown voltage of a vacuum or low-pressure gas like for example R410a can decrease significantly due to the presence of free electrons and ions produced by the arcing. To maintain adequate electrical insulation, a higher pressure gas with a higher dielectric strength may be necessary. Although a vacuum is generally considered a better insulator than R410a due to its low dielectric constant, at very low pressures, the remaining gas in the vacuum chamber may not have a low enough dielectric constant to provide sufficient insulation. In such cases, introducing a gas like R410a could help to increase the dielectric strength and provide better electrical insulation.
However, in most practical electrical insulation applications, a vacuum is still considered the better insulator because it has the lowest dielectric constant of any material, making it highly resistant to the flow of electrical charges. This is why vacuum breakers are commonly used in high-voltage power industries to interrupt the flow of current and prevent arcing.
@@gregdekkers2667
I'm not a scientist so I can't answer for sure. I was under the impression that electrons themselves move slower in a vacuum but the electromagnetic waves move faster in a vacuum up to 90% of the speed of light. I think Vacuum arc plays an important role here as even at low voltage you can have a a high amerage arc.
While AFCI breakers are available they don't work well in HVAC as the arc of the contacts themselves making contact cause nucesance trips.
Take a look at the Fusite plug of a compressor. Theterminals themselves are not insulated. In a vacuum this could be a prime condition for arc that explains why the Copeland engineers had the Fusite blow out. They said it was so violent, part of it stuck in the wall on the opposite side.
I do appreciate and respect the conversation even though we don't completely agree.
For reference
"A vacuum arc can arise when the surfaces of metal electrodes in contact with a good vacuum begin to emit electrons either through heating (thermionic emission) or in an electric field that is sufficient to cause field electron emission. Once initiated, a vacuum arc can persist, since the freed particles gain kinetic energy from the electric field, heating the metal surfaces through high-speed particle collisions. This process can create an incandescent cathode spot, which frees more particles, thereby sustaining the arc. At sufficiently high currents an incandescent anode spot may also be formed.
Electric discharge in vacuum is important for certain types of vacuum tubes and for high-voltage vacuum switches. "
@@love2hvac It's truly captivating. I must say, you've taught me something new and had me pondering it for half a day.
I confess that I was mistaken in believing that a vacuum is always the superior insulator. It appears that the engineers at Copeland identified a specific case where this does not hold true, which I cannot dispute. (even though I initially did)
The insulating properties of a vacuum are not perfect, and under certain conditions, such as in the presence of strong electric fields or charged particles, electrical breakdown can still occur. These cases are often specific and less common than the electrical breakdown in air or other materials.
"As you reduce the air pressure, the mean free path of electrons (the average distance an electron can travel between collisions with air molecules) increases. Initially, this may lead to an increase in the dielectric strength of air. However, as you continue to lower the pressure, the dielectric strength may start to decrease, making it easier for electrical breakdown to occur. This behavior is nonlinear and complex, influenced by factors like the electrode configuration and the specific gas mixture involved.
In summary, the dielectric breakdown of air is not a linear process when transitioning from atmospheric pressure to a vacuum, as it is influenced by various factors and exhibits a complex relationship with pressure."
Hello Ty, can you explain how to perform pump down on ductless system when temperature in the room is lower than it is possible to set on controller? How to force compressor to start if there is no contactor? Thank you for the answer.
Heat the RA sensor with a hair dryer on the indoor unit.
have you ever seen a compressor arc while in a vacum ty
I have not seen it first at but the people at the Copland factory told me it blows the fuseite plug completely out and tuck across the room. They lost specifics about not running the compressor in a vacuum because arcing is a big issue.
It's nonsense. We make vacuum breakers for a reason, to prevent arcing, so windings arcing in a vacuum is unlikely.
Here are some reasons not to run in a vacuum:
Refrigeration compressors are designed to operate within a certain range of operating conditions. Operating a refrigeration compressor with a negative suction line pressure, which means the pressure at the suction inlet of the compressor is lower than the recommended minimum operating pressure, can cause several issues such as:
1. Reduced compressor efficiency: A compressor is designed to compress a refrigerant gas from low to high pressure. When the suction line pressure drops below the recommended minimum, the compressor has to work harder to maintain the required flow rate and discharge pressure. This increased workload reduces the efficiency of the compressor, leading to increased energy consumption.
2. Loss of lubrication: The compressor relies on the refrigerant gas to provide lubrication to the moving parts. When the suction pressure drops below the recommended minimum, the amount of refrigerant gas entering the compressor is reduced, leading to inadequate lubrication. This can cause premature wear of the compressor's moving parts, leading to compressor failure.
When or why would we need to do a pump down ? Please any body knows the answer
When you need to pull and clean the evaporator, replace a metering device, and replace a filter drier. You can pump it down instead of recovering ALL the refrigerant. It's faster and less chance of contamination.
@love2hvac Thank you very much you're the best
Thank for sharing the knowledge. Are all Refrigeration and Air conditioning units designed to pump down the refrigerant or is there any exception? Small refrigeration units that do not have accumulator and large condensing unit are suitable for pump down or not?
there is always exceptions.
They vary greatly and it depends on the engineer who designed what they are trying to accomplish and the cost factor always plays a part.
@@love2hvac Thank you sir
Can you please explain why the high side pressure goes down instead of up?
The service valve is closed, the pressure between the compressor threw condensor to the valve will go up.
There service port is after the valve even though it's on the same component.
The compressor is pulling in refrigerant. So the compressor sucks in refregerant from the suction line, evaporator, metering device and liquid line to the valve.
So the high side pressure on the liquid line drops because the liquid valve is closed and the compressor sucks it in.
So how much of a refrigerant stays in the pipes? Have you ever measure it?
For 420a 0.6 oz. per foot 3/8 liquid line, plus 6oz. for the filter drier, and the long radius elbows add 2.6
@@love2hvac It should be less than this. No? This is the amount of refrigerant that would be in the system if it was operating normally. But you've pumped it down to like 10 psi.
The Goodman condensers contain a built in filter drier.
Do you know if they qualify for pump down?
I would not. The goodman filter drier is before the valve. If you pump it down, how would you change the filter drier.
Some people pump if down and put a new filter drier outside. They leave the old one and. The old one becomes a restriction and damages the compressor.
@@love2hvac The R22 unit 3 ton has 7.5 lbs Could need to recover and reuse.
If it is a micro channel you are not pumping it down. Recover period.
💪👍🇺🇲❄️ is it OK to pumpdown a unit with microchannel coils as long as it has a receiver ?
Yes receiver 💯 good to go
Yes receiver 💯 good to go
Thanks Ty ur the best
Can anyone answer this? I have an evcon residential unit, was just installed a few months ago and was very quite.
Now, when it kicks on, there is a loud buzzing noise. I felt around it a bit and nothing on the outside cage is rattling, nothing caught in the fan. Weird.
Check the contactor.
@@love2hvac thank you
My neighbors heat pump makes one heck of a racket (buzzing noise) on compressor startup, much more than mine by at least 10x. I don't have a hard start kit for my compressor, maybe his does or it's just noisy, not sure...
Never heard arcing in vacuum. There is special class high voltage switches where switching contacts are in vaccum. Agree that can be dammaged but arcing in not a reason for sure.
Copland scroll manual page 18 at the bottom few lines
climate.emerson.com/documents/copeland-scroll-compressors-for-refrigeration-zs09kae-zs11kae-zs13kae-application-guidelines-en-gb-4214008.pdf
Here is a video on vacuum arc
ua-cam.com/video/GS0saABd-1M/v-deo.html
en.m.wikipedia.org/wiki/Vacuum_arc
@@love2hvac Hope you are not using silicone as a vacuum sealant as this guy. Video is joke. Beside that he is using neon transformer that produces tens of tousands volts. Much more than 208 or 460 that regular compressor runs.
@@aleksandarvasilevski7410 do you have any resources to share to back your claim? I'm always willing to lean but everything I find says scroll compressors are at high risk of arcing damage in a vacuum. Copland compressors have much better resources for testing this than I do and I dont have anything to show otherwise.
🥃🍺🙂👍🏻