I once went on a service call to check a small Chiller for an MRI machine. It was for a hospital and the hospital had their own HVAC employees but they couldn't figure out why it wasn't working. So they called a local company and sent me out there. I started the AC system up and within one second, it tripped on head pressure. I hadn't hooked up my gauges yet so I hooked them up and did another restart. Again, the second it started up, my head pressure gauge needle went from ambient to 600 PSI in 1 second! Right away I removed the refrigerant that was in the system because they said their Tech added some refrigerant and it didn't help. The enclosed system was only supposed to have 5 lbs in it; I removed 35 lbs! The technician overcharged it by 7x its capacity, lol.
Thank you for adding "text" on the screen of classroom audience comments. In the past it has be very difficult to hear their comments, being away from the microphone.
Absolutely love this channel. New tech. Graduated trade school last year. Been in the field about a year. These videos have helped me so much. I listen almost everyday. Thank you for the knowledge. 🙏🏾
I am a homeowner in Minnesota and getting addicted to these teaching videos by Bryan. My AC recently, on a very hot day, was constantly running but not cooling enough. I called the pros, and the technician came in and hooked his meters to the outside unit and immediately told me that the pressure is low, and there must be a refrigerant leak, and I needed to get another company to do a leak test on the system because his company doesn't. I brought in another company where they pushed the refrigerant into the compressor, and tested the coil with high pressure nitrogen where they found no leaks (no vacuum was pulled after the pressure test). Then they unsuccessfully tried to charge the system and concluded that the TXV was stuck shut. I didn't feel that the tech was confident in his assessment, so I requested to get a more senior person to assess the issue, he quickly added one lb. of R410A and ran the system for a while but wasn't able to get the superheat below 20 degrees, and he thought that he over charged the system, so he reclaimed some refrigerant but only dropped the superheat to 17 degrees, at that point he concluded that the TXV is stuck closed and told me that I need to replace the coil. The system is less than three years old. Do you guys agree with his assessment? sorry for not providing all of the technical information as the I haven't gotten the lingo down. Thanks in advance for your opinions and advise.
I’m not in hvac, these videos are getting me interested though 😉, but I’ve been picking up bits and pieces and this is so well explained! You’re honestly one of the best teachers I’ve seen in any field!!
Also, subcool will go down when the house is hot. If you charge to 10° subcooling when the house is 90° and go back when the house is 70° the subcooling will be much higher. The TXV will throttle back when the heat load across the indoor coil drops.
Yup, seen this happen on many walkin coolers, if they have a food delivery, and prop open the door, and bringing in tons of product and the kitchen is hot, the big demand on the coil can result in sight glass flashing for a bit. But clears up in a minute when they finally close the door. Same with a house, if the house is 90 degrees, that TXV will have to be wide open just to keep the superheat under 30 degrees maybe, and it's trying to maintain roughly 10 on average at design temps.
Unloaders on the Compressors! My favorite analogy of the metering device is a traffic jam. Everyone is trying to fit through the one open lane and you’re in a high pressure but when it’s finally your turn to get past the wreck, the traffic is spread out and you’re free to drive without running into anyone. So that’s a low pressure. Or it could be a fire alarm In a building and everyone trying to escape through the same door. Great video! As always!
You can also add refrigerant when the system is off by using your recovery machine in reverse. 410a i use a charge compensator with filter driers on the inlet and outlet ( if recovered refrigerant is being re-used ) or if its virgin refrigerant just hook your tank of refrigerant on the inlet and the equipment on the outlet. It'll get it all in there quickly. On commercial equipment this is done a fair amount of time.
I don't work on HVACs, will never work on HVACs, have no interest in every working on HVACs, but find these videos' fascinating to watch lol. Really enjoy learning how it works.
I for one appreciate your position and you're still doing the right thing though because the mere exposure to this will give you peace of mind when you "call the man" that you wouldn't otherwise have...as long as you don't let the Dunning-Kruger effect get the best of you. lol Understanding your own system as much as possible is very helpful. The upside is we don't have to learn them all like the trades people do. I have prevented service calls for intermittent problems from going south by having gained the most thorough understanding of the symptom (not a hypothesis about the cause) that I could before making the phone call. Understanding your particular system will give you further insight into how to observe a symptom when you have it. Tradespeople here please feel free to correct, criticize and/or just plain ridicule if you wish.
Thanks for all of your talks, very helpful. I can see why a txv on a single stage is not so efficient. It's protective in some ways but adds stress to the compressor in another way. Inverter setup is very efficient. High stage testing, full stage sounds more space program.
I was wondering if you could explain a cascade refrigeration cycle. Your videos are very helpful and have helped me a lot over the years. Hopefully you see this!
I grew up with this guy and he actually doesnt know anything about ac's. If you watch closely, you can see him reading the telepromter. Sidenote: he also had a lot of weird habits like leaving farts in peoples mailboxes.
Helped me in diagnosing our chillers issue that has an accumulator and hot gas valve that helps boil refrigerant after the txv before hitting the evaporator water box
1:24 - You _could_ use a recovery machine to ‘recover’ from the cylinder to the system (using a scale, of course) into a one that is off - _assuming_ you already _know_ how much to add.
Up here in the northern states, piston metered coils are still readily sold (13 SEER). I can't tell you how many systems I've come across that were overcharged by a previous tech because of a blocked metering device. They see high subcooling and high superheat and have no idea what's going on. Forget about reading analog gauges. Then that tech condemns the condenser. What I've seen, in my 10 years of working in the HVAC field, is little shards of solder or braze stuck in the center of the piston. When the restriction is removed, either by taking out the restriction and/or replacing the piston with the correct size, that system works as intended. I honestly think critical thinking has gone away and if it's not in a textbook some techs are lost.
Great explanation on charge Thanks .......yes sir ....get in to big of an hurry adding charge to an running system & not waiting long enough can easily quickly over charge one
Overcharged systems compressors will also draw more current, and in extreme cases trip on HP or even I have seen a Rooftop trip a breaker because of overcharge
When you’re saying high stage. Are you just referring to the fan mode on high stage? Thank you. I had a problem today where I worked on an older unit Mitsubishi heat pump. And I added on a head. The old head was working great. The new one was not Heating or cooling. I have a feeling the future values they put on. Didn’t open all the way or there is a maybe a kink. I added refrigerant. The existing unit wasn’t working. So I immediately shut the system down. And I’m going to go back another day. I don’t think it needed refrigerant and I thought it did. Now I need to pull it all out and make sure the correct amount is in there.
this is a great video. I wonder if this is what i got. my home hvac use to blow super cold one day we had electrical outage and then it blew cool, had 3 different hvac companys come out 2 of them both added freon still blowing cool the 3rd guy cleaned the condensor outdoor still same issue. found a video on youtube that maybe the txv valve was plugged with varnished oil. the temp fix was run the heater so it will heat up the txv bulb then run the ac to get the oil moving but only worked for a bit. if i go outside and put water on the condensor coil it gets the ac really cold for a few min but back to blowing cool air.. it does the job has the 20 degree split but does not have the cold bite it use to on a hot day it cant cool the house it feels muggy if there are to many people in living room.. and wont go lower that 76 when b4 it use to go down to 73 on a day when its over 100 any advice?
After recharging my fridge, the suction line is freezing with ice while the fridge itself is still taking too long to freeze and cool. Did the technician overcharge it?
If the suction port was damaged, I’ve turned it off and used a propane torch to feed a few ounces in. Then turn it back on and checked again. For small refrigeration anyway.
About to get back in the field after being stationary for a year and this is a great refresher. Also: Who doesn't use a scale? How can you charge for how much refrigerant you added if you don't have a scale? That's just giving money away!
on the newer 410 systems , have oversized condensers , do you ever educate the new Jr techs. about older delta td on condensers. an lack of capacity of the huge condensers , the charge is critical , an on etxv doesn't the superheat track fighters than a office an txv nice to see your video ,I'm new to this TV stuff , our laptop in my day was a pencil an notebook ,
If I had a little too much freon in a typical residential ac unit would it make my coil not as cold as it should be?, Or are the only negatives are waste of freon, not as efficient, shorter life span. Sounds like that's the case, which would make slightly too much is better then slightly too little.
Can anyone explain why the bottom of the refrigerant accumulator would have ice building up on it (climbing up the accumulator over time) ? Our tech that was just out said he put an extra lb in our system so it's topped off. Is this a symptom of overcharge ?
I just had a unit today. R22 capillary tubes, 32° subcool 1.8 superheat. The customer was saying it was tripping the breaker. Could that be another symptom of overcharge? Thanks in advance.
I got a question. I have a non-inverter mini split and there is only a port on the suction side, no port on the high side, and so there's no way for me to know what the head pressure is. I seriously doubt it uses a TXV and it's definitely a fixed orfice. How do I know if it's overcharged? Because oftentimes I will add refrigerant and the suction pressure will be just below freezing (about 45 psi for R22) and it stays there no matter what.
I see you're based out of Clairmont, FL. Are you teaching your own employees, or do other companies send technicians to you for training? If so, are there any companies from S. FL, like Broward and Palm Beach county that do?
When refrigerant overcharger, its cause compressor current overload, high pressure at condenser unit, high pressure at evaporator and suction line. Supperheat low, oil & liquid comeback to suction line. Subcooling low.
No not really. It looks the same as a high load proper charge. You can see more of the tubes glow brightly yes but it looks the same when under heavy load. I'm not able to tell anyway
What does it mean if my compressor is sweating up to just below the low pressure line? I live on the Texas coast so we have a lot of humidity. A/C cools fine for an old R22 system but I had them put in Nu-Calgon Ultimate seal 7.5 ton and pressure up but they dumped R427a on top of R22. Two years later vapor line is beer can cold sweating and dumping heat. I was just asking about the compressor sweating. Is that normal for being on the coast with high humidity or is it over pressurized? Pressures were left at 78/240...4 ton system.
I had my seer 12 unit replaced by seer 16 (same manufacture) unit. With the new unit I have to lower the thermostat by 4 degrees to have the same level of comfort. With seer 12 unit I set the thermostat at 80 degrees, With the seer 16 unit I have to lower the thermostat to 76 degrees to get the same level of comfort. Any idea why I have to lower the thermostat with the seer 16 unit? Thanks
Can u overcharge a unit by there not being any load let’s say it’s 74 inside and thermostat is satisfied but u drop the temp to check the levels could that mess u up
At about the 13 minute mark you state the increased pressure of the liquid stacking up behind the txv has an influence on it. Why? The txv bulb on the coil manifold, or suction line, is opening and closing based on the temperature of the refrigerant exiting the indoor coil. Is it your position that the increased pressure of an overcharge drives more liquid refrigerant through the txv opening than a properly charged system? If so wouldn't it only be for the amount of time it takes for the txv to react, because it is based on SH. If so, then a dirty coil or failed/failing condenser fan motor would produce the same effect, as would high ambient temps.
He meant that it forces the TXV to throttle, he explained it only briefly but if you watch the animation closely during his voiceover, you can see the cutaway txv closing down.
@@brnmcc01 Why? If the opening/closing is based on the temperature of the refrigerant leaving the coil, as sensed by the txv bulb, what influence does the stacking liquid refrigerant have?
@@jrsmyth9761 Higher pressure differential across the valve means more refrigerant will flow, resulting in the TXV closing down to compensate. Think of it like trying to regulate a sink faucet to exactly 1 gallon per minute of water flow, and your water supply is on a well pump system. If the water pressure drops, you need to open the faucet more, and if the pressure starts to build when your well pump turns on, you'll need to slowly close the faucet to maintain the desired flow. The compressor in this example has a fixed speed, so it can only handle a certain flow rate of refrigerant.
@@jrsmyth9761 more cold refrigerant means more capacity to absorb heat. If there's not enough heat but you're pushing in lots of liquid vapor, there's a chance that doesn't completely boil by the time it reaches the end of the evap and your sensing bulb which means 0 superheat. So the meter reacts by closing down some more. Also remember pressure equals temp so if the liquid coming in is higher temp (pressure) because of an overcharge, what is metered in by the TXV won't have the capacity to absorb as much heat so it might dump more in to bring down superheat but then goes too far and chases it back up and the cycle continues as it opens and closes.
In automotive air conditioning they have a system where you can suck the refrigerant out of the air conditioner and into a storage tank and produce a good vacuum. Then they zero out the scale and then have it start pumping the refrigerant back into the air conditioner until the proper amount of refrigerant by weight is pumped back into the air conditioner. All with the car engine not running Is there any reason why you can not do the same thing with home or commercial air conditioning systems? If you know how much the system is suppose to have, and it should be written down where the access ports are, you should be able to use a refill pump like they use for auto air conditioners to pump refrigerant into a home or commercial air conditioner system.
I'm not a refrigeration tech but I work on cars. When the high side gets too high pressure it just turns off the compressor till the pressure drops. It doesn't keep pumping it. Don't building ac work the same way?
Most quality systems have high and low-pressure valves. Because of the potentially dangerous high pressures, a car engine compressor could create a High-pressure switch is a must.
Definitely made a mistake to your point by adding refrigerant by being impatient. I should have just gone back another day, which I am now anyway. The customer kind of talked me into it and said can you add some? Yeah that was my fault. Should have known better. Adding too much refrigerant make the old unit the existing one, not work as well I immediately shut it down
sorry i have a question i have a vw golf 4 and i change the (filter Dryer thingi) and i put new freon and oil in the system soo sombady help me i well to know when i need again to renew the (Freon Gas) ?? ewery 2 year ewery 5 year never ??? sorry for my bad EN langunge big respect from Montenegro
A lil bit offtopic question, for DIY house installation of small split unit, can I use CO2 instead of nitrogen to check for leaks? I happen to have CO2 tank and as far as i know its pretty inert gas? Will it condense when pulling vaccuum ?
@@voretex4202 Well Co2 is a new modern refrigerant. It's not the Co2 part but the moisture content in the cheap Co2 bottles. The nitrogen sold by one UK refrigerant company has some low moisture as well. I buy a scientific nitrogen gas with a lower moisture level in the specs. Cheaper and I own the bottle.
They're designed to hold very little refrigerant. I had to replace a microchannel coil on a Bohn low temp freezer condensing unit a few years ago that has a flooded head pressure control. With RTPF (round tube, plate fin) condenser coils of this size, it's normal to charge to a clear sight glass, then add an additional 4-6 pounds of refrigerant to the system for it to work properly in the wintertime. But I looked up the manual for this unit, and it only calls for 1.1 pounds of additional refrigerant, because that's all it takes to flood the condenser in the winter! The previous installer had added way too much refrigerant, and the combination of that, plus a dirty coil, plus a hot day busted some of the flat tubes where the aluminum is soldered onto the hot gas header.
So, they're also super easy to damage from a gross overcharge. The Trane microchannel coils haven't been too bad, but some early adopter manufacturers were (and maybe still are) nothing but trouble and quite leaky.
@@brnmcc01 I agree. Super easy to over charge especially in cool weather. Every ounce matters. If you notice, all the AC units have a head pressure switch. I’m surprised your machine didn’t have one. Us old timers are used to the AC systems that have a slow leak and just need a pound or two every year and they’re good for the summer. Can’t do that with micro channels because if it loses a quarter pound, it’s not gonna cool well. And if you attempt to overcharge it a quarter pound to make it last longer, it’ll hit the hps. I’ve heard people say it’s not safe to pump down into one of them, but I figure if it was pumped down when the unit was new, it’ll pump down now. I did practice with a scrap unit to see if I could learn how to solder and repair one of them. No luck at all. I’ve repaired plenty of tube and fin coils and even all aluminum. I really don’t like these, other than they’re easy to wash.
@@brianlittle717 It does have a high pressure cutout, but I think it's the self resetting type so the continuous flexing of the microchannel over and over finally caused metal fatigue cracking, and then the system basically pumped itself out. The low pressure cutout on a freezer is only set to 5 psi, so when I got there, the system was completely empty. Coil was covered by warranty from Heatcraft, but the 10 pounds of R404A wasn't cheap... As far as repairing the coil, the cracks were pretty buried and not very accessible, plus it still had a couple months of warranty left. They are easy to wash, even 12.5 ton Trane voyage units the microchannel coil is single layer, so it's infinitely easier to clean, than having to take the top off to split coils on older versions.
@@brnmcc01 yes it’s definitely easier to wash than the Slip coil voyagers, but I’d rather have those old units any time. Those things were built like tanks. That makes sense that it burst because of short cycling. That’s bad on the compressor and everything else. I prefer the manual reset hps switches. And you’re right about the lps on a freezer. It pumps down and the lps controls the compressor, so even if it’s got just a little bit, as long as the solenoid is open, it’s still gonna cycle.
The engineers are thinking with a properly sized system, it will be running in low stage most of it's working life. High stage is just for those few hot days during a heat wave, high occupancy load from a house party, or recovering from setback when they get home from work etc. It's also more intuitive for the homeowner that doesn't understand how HVAC works. But they will like it if they really crank the thermostat, the system will 'rev up' and run full blast and cool (or heat) the house faster. Once it's at or near setpoint though, we want the system to run as efficiently as possible so the charge should be right on the money on 1st stage in order to achieve this.
So far I have not heard of a 3 zone system or 2 zone system, or a mini split with 2 to 4 or 15 heads etc. Withch in turn is just like a 2 stage unit, Total charge, this business changes like cell phones.
@@jeremynguyen2346 Yes. You should not substitute it for cream in your coffee nor should you substitute it for mouthwash. It is also not recommended that you use the refrigerant for any sort of enema.
As someone who is just an average homeowner, is this noticeable when you start to get puddles of water underneath the AC condenser after a new install?
That might not be overcharge, just from low temperatures inside the house combined with a high outdoor dewpoint will result in a lot of sweating from the suction line and compressor body as well sometimes. With a properly charged system with the indoor temp set to 68 degrees or 20C, the suction line temperature will tend to be about 58 degrees, and when the outdoor wet bulb temp is over 75 degrees, it will result in a huge amount of condensation. Also if you do any kind of work outside in those conditions, you will also sweat like crazy!
This could happen on a correctly charged AND a slightly undercharged unit as well. The suction temperature of the outdoor unit can range anywhere from 45°F-65°F and the compressors are designed to use this to cool itself down. Of course, the colder the line the more condensation gets produced on the surface of the suction line and bottom 2/3rds of the compressor and after some time it will start dripping. Now each compressor and manufacturer are a bit different and you should get a technician with proper tools to check your charge. They need to check pressures, physical line temperatures, outdoor temps and if they are through, indoor supply and return temps to get delta.
@@jasonjohnsonHVAC I was thinking the same. However, a second identical unit at the same home does not drip any puddle of water on concrete pad. Both cool fine and their delta t are same (due to txv metering). So, does this mean that the first unit is overcharged and that too much liquid refrigerant is stacking in the accumulator and boiling-off and causing excess condensation?
@uhfmhz The puddle of water on the concrete pad is under the condenser. Thus, apparently the accumulator is profusely sweating with condensate and dripping into the pad.
@@MaMa-qh4dy Is the one that doesn't have any water for the upstairs? A lot of houses with two systems, they will keep the upstairs unit colder because thats where the bedrooms are, and then the cold air sinks to the lower level, and therefore the lower level has lower heat load on the evap, resulting in much colder return gas temps. Also check your air filters, that one unit could just be dirty air filters.
I see 410a systems with sight glasses.....liquid refrigerant is liquid refrigerant. Of course 410 is near azeotropic so very tiny amount of glide involved. I would think on more blended refrigerant with larger glides, you use the different points of change of state. I shoot for mid point temps.
Heating blanket lol. Sure..
Really good information
I use a heat gun(blow dryer) that's normally used for drying paint.
I'm good on heating blanket, but I'll take an ice bucket! 😅
@@johnharrisonschulzIi73ueQ
He is trying to provide real education for free??? Wow. That's like genuinely trying to help. Exceptional professional
I once went on a service call to check a small Chiller for an MRI machine. It was for a hospital and the hospital had their own HVAC employees but they couldn't figure out why it wasn't working. So they called a local company and sent me out there. I started the AC system up and within one second, it tripped on head pressure. I hadn't hooked up my gauges yet so I hooked them up and did another restart. Again, the second it started up, my head pressure gauge needle went from ambient to 600 PSI in 1 second! Right away I removed the refrigerant that was in the system because they said their Tech added some refrigerant and it didn't help. The enclosed system was only supposed to have 5 lbs in it; I removed 35 lbs! The technician overcharged it by 7x its capacity, lol.
Thats awesome! Wow!
😅😅😅 Jesus
The highest overcharge I’ve seen was on a walk-in cooler: I pulled a little over fifteen pounds out. This one tops mine!
Thank you for adding "text" on the screen of classroom audience comments. In the past it has be very difficult to hear their comments, being away from the microphone.
New to the career field, teachers at my school don’t teach at all. This helps me understand a lot more. Thank you
Absolutely love this channel. New tech. Graduated trade school last year. Been in the field about a year. These videos have helped me so much. I listen almost everyday. Thank you for the knowledge. 🙏🏾
I was so attentive during your lesson. Thanks from Bangladesh.
The better I become as a tech, the more helpful these videos become. Hmmm
I am a homeowner in Minnesota and getting addicted to these teaching videos by Bryan. My AC recently, on a very hot day, was constantly running but not cooling enough. I called the pros, and the technician came in and hooked his meters to the outside unit and immediately told me that the pressure is low, and there must be a refrigerant leak, and I needed to get another company to do a leak test on the system because his company doesn't. I brought in another company where they pushed the refrigerant into the compressor, and tested the coil with high pressure nitrogen where they found no leaks (no vacuum was pulled after the pressure test). Then they unsuccessfully tried to charge the system and concluded that the TXV was stuck shut. I didn't feel that the tech was confident in his assessment, so I requested to get a more senior person to assess the issue, he quickly added one lb. of R410A and ran the system for a while but wasn't able to get the superheat below 20 degrees, and he thought that he over charged the system, so he reclaimed some refrigerant but only dropped the superheat to 17 degrees, at that point he concluded that the TXV is stuck closed and told me that I need to replace the coil. The system is less than three years old. Do you guys agree with his assessment? sorry for not providing all of the technical information as the I haven't gotten the lingo down. Thanks in advance for your opinions and advise.
go away
I’m not in hvac, these videos are getting me interested though 😉, but I’ve been picking up bits and pieces and this is so well explained! You’re honestly one of the best teachers I’ve seen in any field!!
i really like the way you are taking it to the needy. i am hanif in the same hvac service industry for more than 3 decades . great& thank you
Also, subcool will go down when the house is hot. If you charge to 10° subcooling when the house is 90° and go back when the house is 70° the subcooling will be much higher. The TXV will throttle back when the heat load across the indoor coil drops.
Yup, seen this happen on many walkin coolers, if they have a food delivery, and prop open the door, and bringing in tons of product and the kitchen is hot, the big demand on the coil can result in sight glass flashing for a bit. But clears up in a minute when they finally close the door. Same with a house, if the house is 90 degrees, that TXV will have to be wide open just to keep the superheat under 30 degrees maybe, and it's trying to maintain roughly 10 on average at design temps.
Unloaders on the Compressors! My favorite analogy of the metering device is a traffic jam. Everyone is trying to fit through the one open lane and you’re in a high pressure but when it’s finally your turn to get past the wreck, the traffic is spread out and you’re free to drive without running into anyone. So that’s a low pressure. Or it could be a fire alarm In a building and everyone trying to escape through the same door. Great video! As always!
You can also add refrigerant when the system is off by using your recovery machine in reverse. 410a i use a charge compensator with filter driers on the inlet and outlet ( if recovered refrigerant is being re-used ) or if its virgin refrigerant just hook your tank of refrigerant on the inlet and the equipment on the outlet. It'll get it all in there quickly. On commercial equipment this is done a fair amount of time.
Thanks for the tip.
Also helps get every last ounce out
All the time, especially on larger charges.
Might sound like a stupid question but wouldn't that slightly increase the pressure and maybe a slight chance of introducing non condensable
I love the calmness and the way he explained how it works
I don't work on HVACs, will never work on HVACs, have no interest in every working on HVACs, but find these videos' fascinating to watch lol. Really enjoy learning how it works.
I for one appreciate your position and you're still doing the right thing though because the mere exposure to this will give you peace of mind when you "call the man" that you wouldn't otherwise have...as long as you don't let the Dunning-Kruger effect get the best of you. lol Understanding your own system as much as possible is very helpful. The upside is we don't have to learn them all like the trades people do. I have prevented service calls for intermittent problems from going south by having gained the most thorough understanding of the symptom (not a hypothesis about the cause) that I could before making the phone call. Understanding your particular system will give you further insight into how to observe a symptom when you have it.
Tradespeople here please feel free to correct, criticize and/or just plain ridicule if you wish.
Very informative. Good teacher. Excellent techno speak.
Thanks!
Thanks for all of your talks, very helpful. I can see why a txv on a single stage is not so efficient. It's protective in some ways but adds stress to the compressor in another way. Inverter setup is very efficient. High stage testing, full stage sounds more space program.
I was wondering if you could explain a cascade refrigeration cycle. Your videos are very helpful and have helped me a lot over the years. Hopefully you see this!
I grew up with this guy and he actually doesnt know anything about ac's. If you watch closely, you can see him reading the telepromter. Sidenote: he also had a lot of weird habits like leaving farts in peoples mailboxes.
I really wish I had you as my teacher years ago Would have loved to have worked there. Thanks for your time
Helped me in diagnosing our chillers issue that has an accumulator and hot gas valve that helps boil refrigerant after the txv before hitting the evaporator water box
1:24 - You _could_ use a recovery machine to ‘recover’ from the cylinder to the system (using a scale, of course) into a one that is off - _assuming_ you already _know_ how much to add.
Up here in the northern states, piston metered coils are still readily sold (13 SEER). I can't tell you how many systems I've come across that were overcharged by a previous tech because of a blocked metering device. They see high subcooling and high superheat and have no idea what's going on. Forget about reading analog gauges. Then that tech condemns the condenser. What I've seen, in my 10 years of working in the HVAC field, is little shards of solder or braze stuck in the center of the piston. When the restriction is removed, either by taking out the restriction and/or replacing the piston with the correct size, that system works as intended. I honestly think critical thinking has gone away and if it's not in a textbook some techs are lost.
Great explanation on charge Thanks .......yes sir ....get in to big of an hurry adding charge to an running system & not waiting long enough can easily quickly over charge one
Such a great teacher! Its a treasure for us on our learning curve!!
These principals make this a watch more than once video
You are a great teacher! Thank You very much! Greatings from argentina
Awesome teaching. Also measure Compressor power , it will increase than rated value.
Overcharged systems compressors will also draw more current, and in extreme cases trip on HP or even I have seen a Rooftop trip a breaker because of overcharge
You can use a reclaimer to add refrigerant when system is off as well.
When you’re saying high stage. Are you just referring to the fan mode on high stage? Thank you. I had a problem today where I worked on an older unit Mitsubishi heat pump. And I added on a head. The old head was working great. The new one was not Heating or cooling. I have a feeling the future values they put on. Didn’t open all the way or there is a maybe a kink. I added refrigerant. The existing unit wasn’t working. So I immediately shut the system down. And I’m going to go back another day. I don’t think it needed refrigerant and I thought it did. Now I need to pull it all out and make sure the correct amount is in there.
this is a great video. I wonder if this is what i got. my home hvac use to blow super cold one day we had electrical outage and then it blew cool, had 3 different hvac companys come out 2 of them both added freon still blowing cool the 3rd guy cleaned the condensor outdoor still same issue. found a video on youtube that maybe the txv valve was plugged with varnished oil. the temp fix was run the heater so it will heat up the txv bulb then run the ac to get the oil moving but only worked for a bit. if i go outside and put water on the condensor coil it gets the ac really cold for a few min but back to blowing cool air.. it does the job has the 20 degree split but does not have the cold bite it use to on a hot day it cant cool the house it feels muggy if there are to many people in living room.. and wont go lower that 76 when b4 it use to go down to 73 on a day when its over 100 any advice?
I like to think of the droplets discharging from the TXV as an actual cloud of refrigerant.
Do you have any videos or podcasts on zone system problems in multi story homes? And how to overcome those issues?
Learning from Papua New Guinea..
Thankyou
thanks so much for this interesting explanation for AC
Very instructive video. Thank you for your teaching. God bless
After recharging my fridge, the suction line is freezing with ice while the fridge itself is still taking too long to freeze and cool. Did the technician overcharge it?
If the suction port was damaged, I’ve turned it off and used a propane torch to feed a few ounces in. Then turn it back on and checked again. For small refrigeration anyway.
Best hvac content
About to get back in the field after being stationary for a year and this is a great refresher. Also: Who doesn't use a scale? How can you charge for how much refrigerant you added if you don't have a scale? That's just giving money away!
on the newer 410 systems , have oversized condensers , do you ever educate the new Jr techs. about older delta td on condensers. an lack of capacity of the huge condensers , the charge is critical , an on etxv doesn't the superheat track fighters than a office an txv
nice to see your video ,I'm new to this TV stuff , our laptop in my day was a pencil an notebook ,
If I had a little too much freon in a typical residential ac unit would it make my coil not as cold as it should be?, Or are the only negatives are waste of freon, not as efficient, shorter life span. Sounds like that's the case, which would make slightly too much is better then slightly too little.
Hi i have high superheat so add more refrigerant to txv system. But the subcool is decrease and liquid line temp increase.
Great video. thanks
Micro-channel condensers... What is the best method to wash these and prevent them from getting 'waterlogged' and blocking airflow.
You can also add refrigerant when the system is off by holding your torch to the cylinder.
Thank you bryan ore for another good video
Very nice,but do we have a practical problem when there is more refrigerant in our unit?
Love it brayn u made me professional
In a pump overfeed recirculated evaporator the refrigerant should leave?
Explains it very well..
Can anyone explain why the bottom of the refrigerant accumulator would have ice building up on it (climbing up the accumulator over time) ? Our tech that was just out said he put an extra lb in our system so it's topped off. Is this a symptom of overcharge ?
I just had a unit today. R22 capillary tubes, 32° subcool 1.8 superheat. The customer was saying it was tripping the breaker. Could that be another symptom of overcharge? Thanks in advance.
Due to overgas charge
Is it possible to ice build up on suction line?
Please reply
I got a question. I have a non-inverter mini split and there is only a port on the suction side, no port on the high side, and so there's no way for me to know what the head pressure is. I seriously doubt it uses a TXV and it's definitely a fixed orfice. How do I know if it's overcharged? Because oftentimes I will add refrigerant and the suction pressure will be just below freezing (about 45 psi for R22) and it stays there no matter what.
I see you're based out of Clairmont, FL. Are you teaching your own employees, or do other companies send technicians to you for training? If so, are there any companies from S. FL, like Broward and Palm Beach county that do?
Does temperature outside (93) and another reading at (75) cause a low freon indcation at low temps and high feon indication at high temps?
When refrigerant overcharger, its cause compressor current overload, high pressure at condenser unit, high pressure at evaporator and suction line. Supperheat low, oil & liquid comeback to suction line. Subcooling low.
Can i use thermal camera on conderser to detect over/undercharge?
No not really. It looks the same as a high load proper charge. You can see more of the tubes glow brightly yes but it looks the same when under heavy load. I'm not able to tell anyway
8:11 what do they mean with high stage? I'm not natie English. Really usefull video's btw. Thanks alot.
What does it mean if my compressor is sweating up to just below the low pressure line? I live on the Texas coast so we have a lot of humidity. A/C cools fine for an old R22 system but I had them put in Nu-Calgon Ultimate seal 7.5 ton and pressure up but they dumped R427a on top of R22. Two years later vapor line is beer can cold sweating and dumping heat. I was just asking about the compressor sweating. Is that normal for being on the coast with high humidity or is it over pressurized? Pressures were left at 78/240...4 ton system.
Excellent teacher. I would love to talk to him and ask questions.
I had my seer 12 unit replaced by seer 16 (same manufacture) unit. With the new unit I have to lower the thermostat by 4 degrees to have the same level of comfort. With seer 12 unit I set the thermostat at 80 degrees, With the seer 16 unit I have to lower the thermostat to 76 degrees to get the same level of comfort. Any idea why I have to lower the thermostat with the seer 16 unit? Thanks
In Goodman 2 stage communication system you have to run compressor at 1st stage to charge
Yup we learnerd thay after a few installs
You can use the recovery machine to charge a large systems
Can u overcharge a unit by there not being any load let’s say it’s 74 inside and thermostat is satisfied but u drop the temp to check the levels could that mess u up
At about the 13 minute mark you state the increased pressure of the liquid stacking up behind the txv has an influence on it.
Why?
The txv bulb on the coil manifold, or suction line, is opening and closing based on the temperature of the refrigerant exiting the indoor coil.
Is it your position that the increased pressure of an overcharge drives more liquid refrigerant through the txv opening than a properly charged system? If so wouldn't it only be for the amount of time it takes for the txv to react, because it is based on SH.
If so, then a dirty coil or failed/failing condenser fan motor would produce the same effect, as would high ambient temps.
He meant that it forces the TXV to throttle, he explained it only briefly but if you watch the animation closely during his voiceover, you can see the cutaway txv closing down.
@@brnmcc01
Why?
If the opening/closing is based on the temperature of the refrigerant leaving the coil, as sensed by the txv bulb, what influence does the stacking liquid refrigerant have?
@@jrsmyth9761 Higher pressure differential across the valve means more refrigerant will flow, resulting in the TXV closing down to compensate. Think of it like trying to regulate a sink faucet to exactly 1 gallon per minute of water flow, and your water supply is on a well pump system. If the water pressure drops, you need to open the faucet more, and if the pressure starts to build when your well pump turns on, you'll need to slowly close the faucet to maintain the desired flow. The compressor in this example has a fixed speed, so it can only handle a certain flow rate of refrigerant.
@@jrsmyth9761 more cold refrigerant means more capacity to absorb heat. If there's not enough heat but you're pushing in lots of liquid vapor, there's a chance that doesn't completely boil by the time it reaches the end of the evap and your sensing bulb which means 0 superheat. So the meter reacts by closing down some more. Also remember pressure equals temp so if the liquid coming in is higher temp (pressure) because of an overcharge, what is metered in by the TXV won't have the capacity to absorb as much heat so it might dump more in to bring down superheat but then goes too far and chases it back up and the cycle continues as it opens and closes.
In automotive air conditioning they have a system where you can suck the refrigerant out of the air conditioner and into a storage tank and produce a good vacuum. Then they zero out the scale and then have it start pumping the refrigerant back into the air conditioner until the proper amount of refrigerant by weight is pumped back into the air conditioner. All with the car engine not running
Is there any reason why you can not do the same thing with home or commercial air conditioning systems? If you know how much the system is suppose to have, and it should be written down where the access ports are, you should be able to use a refill pump like they use for auto air conditioners to pump refrigerant into a home or commercial air conditioner system.
I'm not a refrigeration tech but I work on cars. When the high side gets too high pressure it just turns off the compressor till the pressure drops. It doesn't keep pumping it. Don't building ac work the same way?
Most quality systems have high and low-pressure valves. Because of the potentially dangerous high pressures, a car engine compressor could create a High-pressure switch is a must.
Keep your heating blanket close to your recovery rags.
Can a 3 ton txv on a 2 ton system cause the coil to freeze
hi, what average pressures should i see on my gages vs ambient temperature.
Lennox does the double row coil in residential
When did they start that?
@@jasonjohnsonHVAC I want to say since they started the Dave lennox signiture series
Carrier 13 seer 4-5 ton also.
Definitely made a mistake to your point by adding refrigerant by being impatient. I should have just gone back another day, which I am now anyway. The customer kind of talked me into it and said can you add some? Yeah that was my fault. Should have known better. Adding too much refrigerant make the old unit the existing one, not work as well I immediately shut it down
Great video as always 👍
sorry i have a question i have a vw golf 4 and i change the (filter Dryer thingi) and i put new freon and oil in the system soo sombady help me i well to know when i need again to renew the (Freon Gas) ?? ewery 2 year ewery 5 year never ??? sorry for my bad EN langunge big respect from Montenegro
A lil bit offtopic question, for DIY house installation of small split unit, can I use CO2 instead of nitrogen to check for leaks? I happen to have CO2 tank and as far as i know its pretty inert gas? Will it condense when pulling vaccuum ?
Absolutely not. Co2 adds moisture to the system which is a huge no no.
@@voretex4202 I see, thanks for answer!
@@voretex4202 Well Co2 is a new modern refrigerant. It's not the Co2 part but the moisture content in the cheap Co2 bottles. The nitrogen sold by one UK refrigerant company has some low moisture as well. I buy a scientific nitrogen gas with a lower moisture level in the specs. Cheaper and I own the bottle.
My rule of thumb when I add refrigerant on a system when still on vacuum is 50psi. So far haven’t been off more than a couple of degrees the superheat
I prefer to use “change of state to gas” rather then “boiling off” - as (I agree) many people equate boiling as “hot”.
Those micro channel condensers are super easy to overcharge.
They're designed to hold very little refrigerant. I had to replace a microchannel coil on a Bohn low temp freezer condensing unit a few years ago that has a flooded head pressure control. With RTPF (round tube, plate fin) condenser coils of this size, it's normal to charge to a clear sight glass, then add an additional 4-6 pounds of refrigerant to the system for it to work properly in the wintertime. But I looked up the manual for this unit, and it only calls for 1.1 pounds of additional refrigerant, because that's all it takes to flood the condenser in the winter! The previous installer had added way too much refrigerant, and the combination of that, plus a dirty coil, plus a hot day busted some of the flat tubes where the aluminum is soldered onto the hot gas header.
So, they're also super easy to damage from a gross overcharge. The Trane microchannel coils haven't been too bad, but some early adopter manufacturers were (and maybe still are) nothing but trouble and quite leaky.
@@brnmcc01 I agree. Super easy to over charge especially in cool weather. Every ounce matters. If you notice, all the AC units have a head pressure switch. I’m surprised your machine didn’t have one. Us old timers are used to the AC systems that have a slow leak and just need a pound or two every year and they’re good for the summer. Can’t do that with micro channels because if it loses a quarter pound, it’s not gonna cool well. And if you attempt to overcharge it a quarter pound to make it last longer, it’ll hit the hps. I’ve heard people say it’s not safe to pump down into one of them, but I figure if it was pumped down when the unit was new, it’ll pump down now. I did practice with a scrap unit to see if I could learn how to solder and repair one of them. No luck at all. I’ve repaired plenty of tube and fin coils and even all aluminum. I really don’t like these, other than they’re easy to wash.
@@brianlittle717 It does have a high pressure cutout, but I think it's the self resetting type so the continuous flexing of the microchannel over and over finally caused metal fatigue cracking, and then the system basically pumped itself out. The low pressure cutout on a freezer is only set to 5 psi, so when I got there, the system was completely empty. Coil was covered by warranty from Heatcraft, but the 10 pounds of R404A wasn't cheap... As far as repairing the coil, the cracks were pretty buried and not very accessible, plus it still had a couple months of warranty left. They are easy to wash, even 12.5 ton Trane voyage units the microchannel coil is single layer, so it's infinitely easier to clean, than having to take the top off to split coils on older versions.
@@brnmcc01 yes it’s definitely easier to wash than the Slip coil voyagers, but I’d rather have those old units any time. Those things were built like tanks. That makes sense that it burst because of short cycling. That’s bad on the compressor and everything else. I prefer the manual reset hps switches. And you’re right about the lps on a freezer. It pumps down and the lps controls the compressor, so even if it’s got just a little bit, as long as the solenoid is open, it’s still gonna cycle.
Why suction line temperature is going down in our HVAC
is this a real class btw school or a evening training ? we have school and practice for 3 and a half year. with theorie and praxis
Legit Question: Why in the install manual for Amana 2 Stage ASXC systems does it say charge unit in first stage?
The engineers are thinking with a properly sized system, it will be running in low stage most of it's working life. High stage is just for those few hot days during a heat wave, high occupancy load from a house party, or recovering from setback when they get home from work etc. It's also more intuitive for the homeowner that doesn't understand how HVAC works. But they will like it if they really crank the thermostat, the system will 'rev up' and run full blast and cool (or heat) the house faster. Once it's at or near setpoint though, we want the system to run as efficiently as possible so the charge should be right on the money on 1st stage in order to achieve this.
hello sir how to know if i have a problem in compressor valve
You mentioned waiting till the coil is dry???
wet coil temps will throw off gauges
On a Goodman two stage system you charge it on first stafirst stage
So far I have not heard of a 3 zone system or 2 zone system, or a mini split with 2 to 4 or 15 heads etc. Withch in turn is just like a 2 stage unit, Total charge, this business changes like cell phones.
Compressor will over amp . Carrier commercial splits have to separate cond coils remove those clips its a lot of fun!
Hi I need help with my car a.c it have 100 plus and minus 50g I have no idea how much is that anyone know how much gas is that
Free tip. Buy a ryobi 600 psi cordless pressure washer I haven’t taken a condenser jacket off in 2 yrs
I've been tryna wrap my head around this stuff for 20 years. I'm just a dumb bakery owner.
What is a refrigerant in hvac
Depends on the system but for most newish homes it’s r410a
It is a chemical composition that allows for heat to be transferred from one location to another
@@chromelemon is refrigerant dangerous
@@jeremynguyen2346 Yes. You should not substitute it for cream in your coffee nor should you substitute it for mouthwash. It is also not recommended that you use the refrigerant for any sort of enema.
As someone who is just an average homeowner, is this noticeable when you start to get puddles of water underneath the AC condenser after a new install?
That might not be overcharge, just from low temperatures inside the house combined with a high outdoor dewpoint will result in a lot of sweating from the suction line and compressor body as well sometimes. With a properly charged system with the indoor temp set to 68 degrees or 20C, the suction line temperature will tend to be about 58 degrees, and when the outdoor wet bulb temp is over 75 degrees, it will result in a huge amount of condensation. Also if you do any kind of work outside in those conditions, you will also sweat like crazy!
I was expecting to hear when you add gas refrigerant instead of liquid or when you can do that
Would an overcharged heat pump in summer cause water to drip from underneath condenser onto the concrete pad?
This could happen on a correctly charged AND a slightly undercharged unit as well. The suction temperature of the outdoor unit can range anywhere from 45°F-65°F and the compressors are designed to use this to cool itself down. Of course, the colder the line the more condensation gets produced on the surface of the suction line and bottom 2/3rds of the compressor and after some time it will start dripping. Now each compressor and manufacturer are a bit different and you should get a technician with proper tools to check your charge. They need to check pressures, physical line temperatures, outdoor temps and if they are through, indoor supply and return temps to get delta.
The accumulator sweats something good.
@@jasonjohnsonHVAC I was thinking the same. However, a second identical unit at the same home does not drip any puddle of water on concrete pad. Both cool fine and their delta t are same (due to txv metering). So, does this mean that the first unit is overcharged and that too much liquid refrigerant is stacking in the accumulator and boiling-off and causing excess condensation?
@uhfmhz The puddle of water on the concrete pad is under the condenser. Thus, apparently the accumulator is profusely sweating with condensate and dripping into the pad.
@@MaMa-qh4dy Is the one that doesn't have any water for the upstairs? A lot of houses with two systems, they will keep the upstairs unit colder because thats where the bedrooms are, and then the cold air sinks to the lower level, and therefore the lower level has lower heat load on the evap, resulting in much colder return gas temps. Also check your air filters, that one unit could just be dirty air filters.
Just assume the condenser is clogged. No one ever cleans them.
Overcharging because you are relying on the sight glass to remove bubbles.
In the old days my father always used a sight glass to charge the system. I guess that is a no no now.
There are still sight glasses on refrigeration systems. Ninety percent are charged that way.
I see 410a systems with sight glasses.....liquid refrigerant is liquid refrigerant. Of course 410 is near azeotropic so very tiny amount of glide involved. I would think on more blended refrigerant with larger glides, you use the different points of change of state. I shoot for mid point temps.