Man you are such a wealth of information. Been in this trade 5 years now and am constantly still learning more or deeper about things. I’ve been riding around in my service truck listening to your videos, thank you man. Please keep them coming
You're the man Ty! I learn so much of the fine details from your videos it's like HVAC engineering 101. With the knowledge provided in your videos the average HVAC mechanic can become a skilled HVAC technician, & not simply a parts changer.
I love these discussions of temp to pressure relationship and understanding the properties of the refrigerant. This is what is all about. Diagnostics comes easier as I learn these scenarios. Thanks for the info. Ty your awesome 👍
Thank you for sharing your knowledge. I’ve been searching for a video on the effects non-condensables has on a system for awhile. Very detailed and informative video. I also found your video with Bryan Orr on leak detection methods very informative. Keep them coming!
I really appreciate your insight, everything you said is correct. Unfortunately, in the real world of business, we don’t generally have the time and the customers don’t want to spend the money to go through an entire process like that. Service technicians have to be able to figure out the issue before we get to the point of pulling out all the refrigerant.
I'm the world of business nothing is mixed, just sell sell sell. There are sales techs that have never replaced a contactor or capacitor. I know somewhere out there, there are going to be techs that want to diagnose and fix, and customers willing to pay for it.
Great video. You should be able to check the txv by raising the head pressures block off air flow or disconnect the fan power. The head pressures rise and the txv should remain constant. Isn't that the test process of the txv.
Thank you for this video! Great explanation with a very easy to follow language/terminology. This video popped up into my UA-cam welcome page and it was a very surprising coincidence….if you believe in coincidences :) Restriction or non-condensible/contamination.., or both?… I was working on an island cooler today with a TXV that doesn’t respond to SuperHeat adjustments and on the top of a plugged screen/retainer on that TXV inlet I believe that someone added/charged r-410 into this r-404 system.. at least my temperature/pressure numbers didn’t match r-404.
Thanks! Mixed refrigerants makes all diagnostics difficult because we never know what the SH or SC is since we don't know what the saturation point is. Mixing refrigerants changes the PT points of all the refrigerants.
SubCooling is a very nice thing to measure, but pretty much useless fir refrigeration applications… at least from my experience. However, TD in the condenser coil is kind of more reliable thing… However, if it’s an inverter/variable speed compressor it becomes useless as well… SuperHeat rules! :),
Why would your head pressure go up with a partial restriction, when you are essentially pumping the system down? Your not picking up much heat in the starved evap coil. So you don’t need all the space in the condenser. Usually the head pressure won’t go up unless you run out of space in the condenser.
Because the condensor will have much less internal condensing volume and since you're technically pumping down the system, you'll continue to compress and discharge refrigerent faster than it can condense driving up the discharge pressure.
I have not heard such a detailed description of noncondensibles and the possible side effects and diagnosis since my father started instructing me in the late 1970s. My father also show me a tank filled with R12 Put it in the freezer with the temperature below -22°F because that’s roughly the boiling point of R12. If you had noncondensibles mixed you would have a pressure that you can read If you had pure R12 you would have zero psi. And the bleed off procedure to do this properly would be done over many hours or days. Because you would have to bleed off the refrigerant so slowly as to not lower the temperature of the refrigerant in the bottle. At the same time the noncondensibles are actually mixed and combined inside the liquid refrigerant exactly the same CO2 is in liquid water in a bottle of Coca-Cola. You reseal the container let it set overnight in a temperature stable room at 70°F as the temperature rises from your bleeding procedure the noncondensibles some of it would come out of the liquid refrigerant and rise to the top again. Later in 1992 we purchased a Bacharach refrigerant analyzer. You can prove this and actually measure it to see how many times you had to produce the bleed procedure to come down to 0% air.
This is such a great video, I've never seen such a great comparison between restrictions and non-condensables. Thanks so much. What is the difference between Evaporator TD and Evaporator delta T? thanks again.
Delta T is same media in and out. Example air in, air out. TD is two Different. Example air in vs refrigerant. A lot more detail here are the 2 videos that go into detail. Delta T ua-cam.com/video/pPRJqDoVCXc/v-deo.html TD ua-cam.com/video/VzRq_36zqcg/v-deo.html
@R P my videos on TXV under the play list learn HVACR HVAC 060 introduction to the TXV TEV HVAC 061 TXV TEV part 2 with target subcooling HVAC 062 TXV/TEV target superheat HVAC 063 TXV/TEV with superheat and subcooling. HVAC 091 EXV EEV electronic expansion valve.
Thanks for sharing your knowledge! Your video reminded me of a noise that has been going on for years and I'm wondering if you may have some ideas. Residential heat pump in AC mode, fixed orifice. If I put my ear up to the liquid line a few feet from where it enters the indoor unit, there is a gurgling sound that lasts about 15 seconds, every 3~5 minutes. It's been a long time since I timed it but it occurs almost to the second each time. It sounds like maybe air bubbles or the liquid is not filling the line completely. I can also hear it just standing close to the unit.
Can you make a video explaining a restriction in the evaporator coil. We do multi family new construction and we’re having to replace a lot of evap coils due to restrictions but we’re not really sure why yet. Common scenario is….Compressor goes bad and name tag looks brownish like the compressor has been over heating. Once compressor is replaced we realized evap is clogged, we think it’s oil from compressor somehow? Also scroll plates brake into pieces
Biggest killer for compressors is overheat form compression ratio. Biggest cause for high compression ratio is the low side pressure is to low. This leads me to believe your restriction is what killing the compressor. Restriction is typically in capillary metering devices, it the screen before or at the a fixed or TXV device, and the distribution tubes. This is primarily from oxidation for not brazing with a nitrogen flow, not protecting the lines when they are open, soft solder or flux inside the connections and piping. Restrictions inside the evaporator coil themselves, damaged tubing, attempted leak repair in the coil is most common. If it is a Heat Pump there will be many more causes. The evaporator might be too small for the compressor. Missmatched system. Also could be a restriction on the high side, such as 2 filter driers, or a cloged filter drier, or airflow on the condensor is recirculated. Part 2 refregerants In compatible refregerants or fractured refregerant blends. It may not work with the system or it may not work with the oil in the system. Mixed refregerants Part 3 broken scrolls is usually from liquid flood back or Liquid slugging. Liquid refregerant entering the scroll set. 1 liquid slugging, the evaporator is not boiling all the refregerant into a vapor, liquid slugs the compressor because A. Over charged B. Bad airflow/dirty coil filter ext ext C. Improper metering for metering device. 2 Flooded start, refregerant entering the scroll set at startup. A overcharged B needs a crank case heater That should lead you to the problem.
Around the 8:25 mark, you said that the Condenser TD will go down. Having trouble understanding that part. Why so? Because the saturated goes up wouldn't the air the coil up causing it to be farther apart from the ambient air being pulled in?
8:25 in reference to non condesables and the condenser. The condensor TD (refregerants vs Air in) will go up. The non condesables has contamination making a higher head pressure. The difference between the refregerants boiling and the air temperature will be farther apart (higher TD) because we are not getting a true saturated temperature. The Delta T (air in vs air out) will go down because we are moving less BTU of heat energy. The higer head pressure means less overall volume or refregerants pumped and less refregerants changing state meaning less heat rejected. Rejecting less heat into the air means the air will change less. This is why condensor Delta T drops. I hope that helps.
Hello Ty very informative as usual my question is if you have Noncondensibles in an R22 system as opposed to a system with a blended refrigerant in it will the reaction in system be the same thank you.
Hey ty appreciate for your explanation. But why when you talk about restriction non-condensible gases as a restriction you write down superheat it will low ( that what I think) and then change to high .
The problem with that is sometimes they dissolve and change the boiling point. Ethyl alcohol and water for instance, at 97% ethanol in the e mixture, the water boils at the same temperature as the ethanol instead of at 100C, the same can happen with mixing refrigerants, quite unpredictably. Azeotropic refrigerants do this perfect mix so they behave like a single molecule instead of having several boiling points.
A quick non condensable test.....Un plug the compressor....let the condenser fan run for 15 minutes.....then check your standing pressure. It should tell you.
So getting the static temp at the outlet side of my condenser should be step number one so I can identify the refrigerant. If you have two types of refrigerant I was told the pressure is the sum of those two types. It will drastically change the pressure
so if you restore the refrigerant into the condenser and change the txv do you do the whole process again? nitro pressure test and vacuum? why is easier?
My favorite at 21:30 second favorite at 16:32 both in this video ua-cam.com/video/iJTMR_jLcjc/v-deo.html This style you would have to use tubing cutters, I sweat or replace the fitting with the screen pressed I to it. Jump to 1:34 of this video ua-cam.com/video/lAIV0PsN6nc/v-deo.html
What if your pressures fluctuate on the low side. On a r404 I have a walk in cooler that temps and sometimes doesn’t when I checked my pressure on the low side it bounces around
One question sir from a lost new tech. What if you turned off your unit and let your refrigerant settle for some time to then go and check the temperature and pressure in your system to see if that matches a temperature-pressure chart. Could that work to check for non-condensables?
So you would take the tank pressure and temperature and subtract it and compare it to the pt chart that is compatible with that refrigerant ? Im just kind of confused
The tank temperature and pressure should match the chart. Get the refregerant in the tank. Get the temperature of the tank. Get the pressure of the tank. On the TP chart find the refregerant Then mach the temperature the tank was to the temperature in the chart. That will give you a pressure, the pressure of the chart should be the same as the pressure in the tank on your guages.
Couldn't you just shut the system off? Let the pressure settle and then compare the pressure temperature relationship between the refrigerant and the actual PT chart?
I have a building with a 12 tons with no thermostat wire coming to the condenser but the thermostat wires going to two solenoids controlling the liquid lines going to two TXVs, and they control one of condenser fan by pressure switch on the low side, this unit always shuts off and I have to restart the electrical breaker each morning any advice please.
Quick check for non-condensables in system. Turn off unit n watch head pressure. It should steadily drop. If head pressure stays for a bit then Slowly drops could b noncondensables. Also try taking temp of line going into condenser, leaving condenser n ambient with the unit off. When all 3 r equal convert head psi to saturation temp using chart. If different from other 3 good chance of noncondensables. Great class TYB 💪👍🐕 thanks
Hey! are u sure thats true ?? "Turn off unit n watch head pressure. It should steadily drop. If head pressure stays for a bit then Slowly drops could b noncondensables." if this is true, it can be huge help in diagnosis....and question to the part 2 " taking temp of line going into condenser, leaving condenser n ambient with the unit off. " how long after turning off the device do you measure these 3 points?
@@hbo7799 yes its a good way to check for noncondensables. Read Dick wirz book commercial refrigeration for AC techs n go to chapter 7 troubleshooting.
Unfortunately companies are only paying sales techs good pay. We need to be rewarding skilled and knowledgeable tradespeople. Anybody can sell something, skills and knowledge actually fix and install correctly.
Hello Ty. Thank you for the video. I wanted to ask you: Why does Bryan Orr insist on identifying restriction with "normal to low" head pressure? (see: ua-cam.com/video/s74ex8Nefgc/v-deo.html) My experience with chillers(with large receivers) is the same. But with a freezer with piston compressor and a blocked cap tube, the pressure goes sky rocketing. Every one else that I've seen in the Internet agrees with this, Including yourself in this video.
Bryan is right, but by the time we are seeing a restriction we have generally added refrigerant. Let me expaine some of the differences. #1 The receiver makes a huge difference because the liquid has someplace to go without affecting the head pressure. It will almost always follow the rule Bryan was talking about until you get to the point the receiver is overfilled or flooded. Which unfortunately, I have seen too many times, then the head pressure will rise after that. #2 Without a receiver, it will depend on the coil size. If you notice over the years higher efficiency units have larger evaporator coils. If it's tube and fin, it will have more volume inside and will blow it to work similar to a receiver. However some of these coils are larger but use smaller tubing and smaller internal volume. Especially when you consider a micro channel coil with very little volume. It will not have the space. For the refrigerant to stack and the pressure will rise quickly. Older condensors in the 70's and 80's often had small condensors and a restriction was quickly identified. #3 the metering device. 3A: fixed If we are looking at a fixed Metering device, or Cap tube, we are charging to superheat. If we have a restriction, we don't even see how much refrigerant is being added above the correct level. By the time we get enough refrigerant in the systems, it will have filled the high side with liquid forcing the pressure to go up. So initially it just looked low on charge and after adding refrigerant we can then see the restriction. Note like Bryan was saying the restriction was already there but now the overcharged had it shown up. It's the high side pressure that forces the refrigerant into the low side. So by the time we get enough high side pressure to change the blow side, it's now too high. 3B: TXV With TXV restrictions, the TXV will try to open more and more to allow more refrigerant into the coil. So depending on how bad the restriction is the TXV tries to compensate and the restriction becomes the metering device. There will be a turning point where the restriction becomes too large. We will see the high superheat, add refrigerant until we realize we added too much or until the high side becomes flooded and starts to rise. Finally In your example of a freezer with a blocked cap tube, it will have a lower volume condensor and a cap tube cannot open at all so 2x restrictions. So the condensor side will flood and force the head pressure up typically without adding any refrigerant. The higher compression ratio will likely provide enough heat to keep the high side high. In the spring I will see if I can make some videos showing this
I agree with everything you say, since it agrees with my experience, and also other's. But in your video (3:20 min) you say that head pressure is going up without any of the reservations you mentioned in your reply. If liquid storage size is such a major factor, I think that both your and Bryan should have mentioned it. In my case, a small freezer, with the proper amount of refrigerant(after vacuuming and filling to the manufacturer specs.), with a cap tube blocked, climbed up to above 600 psi before I turned it off. Needless to say that suction side went below zero. Many people I saw on the internet have experienced the same pressure rise when the cap tube is blocked. On the other hand, with my 25TR chillers with a large receiver, I'm used to pump down(shutting the liquid valve) without any increase in head pressure.
@@kamozoren This video is part of a series that represents the first module of a course. Much more details will be covered in my advanced course and diagnostics course. It just takes time and money to make it happen.
Thank you taking the time to answer in such a detailed manner. It shows your deep passion for the trade. I can't thank you enough for your educational videos.
22 is relatively odorless but in higher concentrations it has a chemical almost sweet smell but I dont recommend sniffing it by any means. If the compressor was burning up internally it would not last but a few hours so that's unlikely. It could also be contaminants on the coil, UV ligts or so called "air cleaners/scrubbers" that make a unique smell. Possible other electrical connections such as a relay going bad would be something to check.
Thanks for teaching from your knowledge my friend i learn a lot from your videos.
Man you are such a wealth of information. Been in this trade 5 years now and am constantly still learning more or deeper about things. I’ve been riding around in my service truck listening to your videos, thank you man. Please keep them coming
Thank you. I appreciate the sport!
You're the man Ty! I learn so much of the fine details from your videos it's like HVAC engineering 101. With the knowledge provided in your videos the average HVAC mechanic can become a skilled HVAC technician, & not simply a parts changer.
You're the best, Ty! Always very informative with so much enthusiasm!
I love these discussions of temp to pressure relationship and understanding the properties of the refrigerant. This is what is all about. Diagnostics comes easier as I learn these scenarios. Thanks for the info. Ty your awesome 👍
Thank you
Thank you for sharing your knowledge. I’ve been searching for a video on the effects non-condensables has on a system for awhile. Very detailed and informative video. I also found your video with Bryan Orr on leak detection methods very informative. Keep them coming!
Thank you for the video dealing with this issue now with a unit and you touched on a couple things that really help thank you
Basically a whole chapter of your Esco study guide in 14 minutes. Subscribing
I really appreciate your insight, everything you said is correct. Unfortunately, in the real world of business, we don’t generally have the time and the customers don’t want to spend the money to go through an entire process like that. Service technicians have to be able to figure out the issue before we get to the point of pulling out all the refrigerant.
I'm the world of business nothing is mixed, just sell sell sell.
There are sales techs that have never replaced a contactor or capacitor.
I know somewhere out there, there are going to be techs that want to diagnose and fix, and customers willing to pay for it.
Thank you for your video. So much information to learn.
HI THERE!!! I.M FROM VENEZUELA GOD BLESS YOU FOR SHARING YOUR ACKNOWLEDGMENT .
One of the best mentors on YT
Amazing-my favorite professor!
Awww thank you
Thanks man very much. To teaching us. Keep it up.
Great video. You should be able to check the txv by raising the head pressures block off air flow or disconnect the fan power. The head pressures rise and the txv should remain constant. Isn't that the test process of the txv.
Thank you for this video! Great explanation with a very easy to follow language/terminology. This video popped up into my UA-cam welcome page and it was a very surprising coincidence….if you believe in coincidences :)
Restriction or non-condensible/contamination.., or both?… I was working on an island cooler today with a TXV that doesn’t respond to SuperHeat adjustments and on the top of a plugged screen/retainer on that TXV inlet I believe that someone added/charged r-410 into this r-404 system.. at least my temperature/pressure numbers didn’t match r-404.
Thanks!
Mixed refrigerants makes all diagnostics difficult because we never know what the SH or SC is since we don't know what the saturation point is.
Mixing refrigerants changes the PT points of all the refrigerants.
SubCooling is a very nice thing to measure, but pretty much useless fir refrigeration applications… at least from my experience. However, TD in the condenser coil is kind of more reliable thing… However, if it’s an inverter/variable speed compressor it becomes useless as well… SuperHeat rules! :),
Thank you Ty.
Why would your head pressure go up with a partial restriction, when you are essentially pumping the system down? Your not picking up much heat in the starved evap coil. So you don’t need all the space in the condenser. Usually the head pressure won’t go up unless you run out of space in the condenser.
Because the condensor will have much less internal condensing volume and since you're technically pumping down the system, you'll continue to compress and discharge refrigerent faster than it can condense driving up the discharge pressure.
Amazing video thank you
Thank you very much
great job TY!
I have not heard such a detailed description of noncondensibles and the possible side effects and diagnosis since my father started instructing me in the late 1970s.
My father also show me a tank filled with R12 Put it in the freezer with the temperature below -22°F because that’s roughly the boiling point of R12.
If you had noncondensibles mixed you would have a pressure that you can read
If you had pure R12 you would have zero psi.
And the bleed off procedure to do this properly would be done over many hours or days. Because you would have to bleed off the refrigerant so slowly as to not lower the temperature of the refrigerant in the bottle.
At the same time the noncondensibles are actually mixed and combined inside the liquid refrigerant exactly the same CO2 is in liquid water in a bottle of Coca-Cola.
You reseal the container let it set overnight in a temperature stable room at 70°F as the temperature rises from your bleeding procedure the noncondensibles some of it would come out of the liquid refrigerant and rise to the top again.
Later in 1992 we purchased a Bacharach refrigerant analyzer. You can prove this and actually measure it to see how many times you had to produce the bleed procedure to come down to 0% air.
This is such a great video, I've never seen such a great comparison between restrictions and non-condensables. Thanks so much.
What is the difference between Evaporator TD and Evaporator delta T? thanks again.
Delta T is same media in and out. Example air in, air out.
TD is two Different.
Example air in vs refrigerant.
A lot more detail here are the 2 videos that go into detail.
Delta T
ua-cam.com/video/pPRJqDoVCXc/v-deo.html
TD
ua-cam.com/video/VzRq_36zqcg/v-deo.html
You Spanish is good brother 😂32 treinta y dos , I like watching your video .
Great Info man!!!
Thank you Mr.Ty if the restrictions in the TXV how we can diagnose that? Thanks 🌿
Yes! I have a whole series planed for TXV diagnostics!
@R P my videos on TXV under the play list learn HVACR
HVAC 060 introduction to the TXV TEV
HVAC 061 TXV TEV part 2 with target subcooling
HVAC 062 TXV/TEV target superheat
HVAC 063 TXV/TEV with superheat and subcooling.
HVAC 091 EXV EEV electronic expansion valve.
Good stuff
Thanks for sharing your knowledge! Your video reminded me of a noise that has been going on for years and I'm wondering if you may have some ideas. Residential heat pump in AC mode, fixed orifice. If I put my ear up to the liquid line a few feet from where it enters the indoor unit, there is a gurgling sound that lasts about 15 seconds, every 3~5 minutes. It's been a long time since I timed it but it occurs almost to the second each time. It sounds like maybe air bubbles or the liquid is not filling the line completely. I can also hear it just standing close to the unit.
Very good video thank you
Can you make a video explaining a restriction in the evaporator coil. We do multi family new construction and we’re having to replace a lot of evap coils due to restrictions but we’re not really sure why yet. Common scenario is….Compressor goes bad and name tag looks brownish like the compressor has been over heating. Once compressor is replaced we realized evap is clogged, we think it’s oil from compressor somehow? Also scroll plates brake into pieces
Biggest killer for compressors is overheat form compression ratio.
Biggest cause for high compression ratio is the low side pressure is to low. This leads me to believe your restriction is what killing the compressor.
Restriction is typically in capillary metering devices, it the screen before or at the a fixed or TXV device, and the distribution tubes. This is primarily from oxidation for not brazing with a nitrogen flow, not protecting the lines when they are open, soft solder or flux inside the connections and piping.
Restrictions inside the evaporator coil themselves, damaged tubing, attempted leak repair in the coil is most common. If it is a Heat Pump there will be many more causes.
The evaporator might be too small for the compressor. Missmatched system.
Also could be a restriction on the high side, such as 2 filter driers, or a cloged filter drier, or airflow on the condensor is recirculated.
Part 2 refregerants
In compatible refregerants or fractured refregerant blends. It may not work with the system or it may not work with the oil in the system.
Mixed refregerants
Part 3 broken scrolls is usually from liquid flood back or Liquid slugging. Liquid refregerant entering the scroll set.
1 liquid slugging, the evaporator is not boiling all the refregerant into a vapor, liquid slugs the compressor because
A. Over charged
B. Bad airflow/dirty coil filter ext ext
C. Improper metering for metering device.
2 Flooded start, refregerant entering the scroll set at startup.
A overcharged
B needs a crank case heater
That should lead you to the problem.
Sir please discuss on partwinding cannection compressor
Good 👍
Sir please discuss on screw compressor refrigerant cycle and also discuss loading unloading sequence in screw compressor
I am a long ways form covering screw compressors.
Around the 8:25 mark, you said that the Condenser TD will go down. Having trouble understanding that part. Why so? Because the saturated goes up wouldn't the air the coil up causing it to be farther apart from the ambient air being pulled in?
8:25 in reference to non condesables and the condenser.
The condensor TD (refregerants vs Air in) will go up. The non condesables has contamination making a higher head pressure. The difference between the refregerants boiling and the air temperature will be farther apart (higher TD) because we are not getting a true saturated temperature.
The Delta T (air in vs air out) will go down because we are moving less BTU of heat energy.
The higer head pressure means less overall volume or refregerants pumped and less refregerants changing state meaning less heat rejected. Rejecting less heat into the air means the air will change less. This is why condensor Delta T drops.
I hope that helps.
Hello Ty very informative as usual my question is if you have Noncondensibles in an R22 system as opposed to a system with a blended refrigerant in it will the reaction in system be the same thank you.
Yes it will.
@@love2hvac thank for you feedback
Hey ty appreciate for your explanation.
But why when you talk about restriction non-condensible gases as a restriction you write down superheat it will low ( that what I think) and then change to high .
I would love to see the static pressure of two types of refrigerant mixed.
The problem with that is sometimes they dissolve and change the boiling point. Ethyl alcohol and water for instance, at 97% ethanol in the e mixture, the water boils at the same temperature as the ethanol instead of at 100C, the same can happen with mixing refrigerants, quite unpredictably. Azeotropic refrigerants do this perfect mix so they behave like a single molecule instead of having several boiling points.
Do you have a video planned for where to take used refrigerant to for disposal?
Yea sir! Hopefully before long
A quick non condensable test.....Un plug the compressor....let the condenser fan run for 15 minutes.....then check your standing pressure. It should tell you.
So getting the static temp at the outlet side of my condenser should be step number one so I can identify the refrigerant. If you have two types of refrigerant I was told the pressure is the sum of those two types. It will drastically change the pressure
Head pressure does not go up with a liquid restriction. Pump a system down and watch your gauge. I will be lower than normal.
Sir please one video make on hvac approach temperature in aircool chiller and watercool chiller
Would you see flashing on the sight glass if it was filter drier before sight glass
Sometimes but not always since it usually collects at the top of the condensor.
so if you restore the refrigerant into the condenser and change the txv do you do the whole process again? nitro pressure test and vacuum? why is easier?
👌👌
Do you sweat out the line set from the TXV inlet? Or how to you get the strainer out?
My favorite at 21:30 second favorite at 16:32 both in this video
ua-cam.com/video/iJTMR_jLcjc/v-deo.html
This style you would have to use tubing cutters, I sweat or replace the fitting with the screen pressed I to it.
Jump to 1:34 of this video
ua-cam.com/video/lAIV0PsN6nc/v-deo.html
What if your pressures fluctuate on the low side. On a r404 I have a walk in cooler that temps and sometimes doesn’t when I checked my pressure on the low side it bounces around
One question sir from a lost new tech. What if you turned off your unit and let your refrigerant settle for some time to then go and check the temperature and pressure in your system to see if that matches a temperature-pressure chart. Could that work to check for non-condensables?
Only if the indoor temperature where the evaporator coil is and the outdoor is the same temperature.
@@love2hvac Given that it is very unlikely, it's a big no hahah. Thanks a lot.
So you would take the tank pressure and temperature and subtract it and compare it to the pt chart that is compatible with that refrigerant ? Im just kind of confused
The tank temperature and pressure should match the chart.
Get the refregerant in the tank.
Get the temperature of the tank.
Get the pressure of the tank.
On the TP chart find the refregerant
Then mach the temperature the tank was to the temperature in the chart.
That will give you a pressure, the pressure of the chart should be the same as the pressure in the tank on your guages.
Restriction in liquid line can't cause higher pressure in condenser. Extreme situation such as pump down
I dont understand brazing with nitrogen.
Couldn't you just shut the system off? Let the pressure settle and then compare the pressure temperature relationship between the refrigerant and the actual PT chart?
Sir I’m sorry to bother you since you help everyone with your classes. I need help with 608 preparation test. Thank you
I have some videos on the EPA preparation. Also Bryan Orr with HVAC school has the entire EPA 608 power points presentation on their channel.
I have a building with a 12 tons with no thermostat wire coming to the condenser but the thermostat wires going to two solenoids controlling the liquid lines going to two TXVs, and they control one of condenser fan by pressure switch on the low side, this unit always shuts off and I have to restart the electrical breaker each morning any advice please.
Shutting off meaning they trip the breaker and you have to reset or you shut the breaker off each night?
@@love2hvac Mr. Ty Excuse my language, I meant the compressor tripped during the freeze of vapor line.
You have a problem.
What is the suction superheat?
@@love2hvac suction superheat(13.3 f), and subcooling is 8 f at 88f ambient temperature.
Quick check for non-condensables in system. Turn off unit n watch head pressure. It should steadily drop. If head pressure stays for a bit then Slowly drops could b noncondensables. Also try taking temp of line going into condenser, leaving condenser n ambient with the unit off. When all 3 r equal convert head psi to saturation temp using chart. If different from other 3 good chance of noncondensables. Great class TYB 💪👍🐕 thanks
Hey! are u sure thats true ?? "Turn off unit n watch head pressure. It should steadily drop. If head pressure stays for a bit then Slowly drops could b noncondensables." if this is true, it can be huge help in diagnosis....and question to the part 2 " taking temp of line going into condenser, leaving condenser n ambient with the unit off. " how long after turning off the device do you measure these 3 points?
@@hbo7799 yes its a good way to check for noncondensables. Read Dick wirz book commercial refrigeration for AC techs n go to chapter 7 troubleshooting.
@@hbo7799 when line in n out r same as ambient then concert condensing psi to saturation temp. If not the same as other temp could b noncondensables
It's too bad that this trade doesn't pay well. The migrants will be the new hvac technicians of tomorrow.
Unfortunately companies are only paying sales techs good pay.
We need to be rewarding skilled and knowledgeable tradespeople.
Anybody can sell something, skills and knowledge actually fix and install correctly.
Hello Ty. Thank you for the video. I wanted to ask you: Why does Bryan Orr insist on identifying restriction with "normal to low" head pressure? (see: ua-cam.com/video/s74ex8Nefgc/v-deo.html) My experience with chillers(with large receivers) is the same. But with a freezer with piston compressor and a blocked cap tube, the pressure goes sky rocketing. Every one else that I've seen in the Internet agrees with this, Including yourself in this video.
Bryan is right, but by the time we are seeing a restriction we have generally added refrigerant. Let me expaine some of the differences.
#1 The receiver makes a huge difference because the liquid has someplace to go without affecting the head pressure. It will almost always follow the rule Bryan was talking about until you get to the point the receiver is overfilled or flooded. Which unfortunately, I have seen too many times, then the head pressure will rise after that.
#2 Without a receiver, it will depend on the coil size.
If you notice over the years higher efficiency units have larger evaporator coils. If it's tube and fin, it will have more volume inside and will blow it to work similar to a receiver. However some of these coils are larger but use smaller tubing and smaller internal volume. Especially when you consider a micro channel coil with very little volume. It will not have the space. For the refrigerant to stack and the pressure will rise quickly. Older condensors in the 70's and 80's often had small condensors and a restriction was quickly identified.
#3 the metering device.
3A: fixed
If we are looking at a fixed Metering device, or Cap tube, we are charging to superheat. If we have a restriction, we don't even see how much refrigerant is being added above the correct level. By the time we get enough refrigerant in the systems, it will have filled the high side with liquid forcing the pressure to go up. So initially it just looked low on charge and after adding refrigerant we can then see the restriction. Note like Bryan was saying the restriction was already there but now the overcharged had it shown up.
It's the high side pressure that forces the refrigerant into the low side. So by the time we get enough high side pressure to change the blow side, it's now too high.
3B: TXV
With TXV restrictions, the TXV will try to open more and more to allow more refrigerant into the coil. So depending on how bad the restriction is the TXV tries to compensate and the restriction becomes the metering device. There will be a turning point where the restriction becomes too large. We will see the high superheat, add refrigerant until we realize we added too much or until the high side becomes flooded and starts to rise.
Finally
In your example of a freezer with a blocked cap tube, it will have a lower volume condensor and a cap tube cannot open at all so 2x restrictions. So the condensor side will flood and force the head pressure up typically without adding any refrigerant.
The higher compression ratio will likely provide enough heat to keep the high side high.
In the spring I will see if I can make some videos showing this
I agree with everything you say, since it agrees with my experience, and also other's. But in your video (3:20 min) you say that head pressure is going up without any of the reservations you mentioned in your reply. If liquid storage size is such a major factor, I think that both your and Bryan should have mentioned it. In my case, a small freezer, with the proper amount of refrigerant(after vacuuming and filling to the manufacturer specs.), with a cap tube blocked, climbed up to above 600 psi before I turned it off. Needless to say that suction side went below zero. Many people I saw on the internet have experienced the same pressure rise when the cap tube is blocked. On the other hand, with my 25TR chillers with a large receiver, I'm used to pump down(shutting the liquid valve) without any increase in head pressure.
@@kamozoren
This video is part of a series that represents the first module of a course. Much more details will be covered in my advanced course and diagnostics course.
It just takes time and money to make it happen.
Thank you taking the time to answer in such a detailed manner. It shows your deep passion for the trade. I can't thank you enough for your educational videos.
I guess if the building owner is willing to pay, just replace the thermostat and add virgin refrigerant instead of doing all that work.
Ty thank you.
Please talk slower
I think we use our reclaimer one time !🤣
"Copper hotdog" 😆
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Stay safe.
Retired (werk'n)keyboard super tech. Wear your safety glasses!
Thanks!
22 is relatively odorless but in higher concentrations it has a chemical almost sweet smell but I dont recommend sniffing it by any means.
If the compressor was burning up internally it would not last but a few hours so that's unlikely.
It could also be contaminants on the coil, UV ligts or so called "air cleaners/scrubbers" that make a unique smell.
Possible other electrical connections such as a relay going bad would be something to check.