Liquid Line Restriction! What Happens to High Side Pressure & Subcooling?

In this video, I show how a Liquid Line Restriction Affects The Liquid Pressure and Subcooling. I go over the indicators of a Restriction such as vapor saturated temp, superheat, subcooling, & Delta T. A restriction could be caused by a clogged strainer, clogged metering device, a TXV with low bulb pressure, or a filter drier. Supervision is needed by a licensed HVACR Tech while performing tasks as Experience and Apprenticeship garners Wisdom and Safety.
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Information in this video is intended for educational purposes only. Any work related to the topics in this video should be performed by licensed technicians or by apprentices under the supervision of licensed technicians. AC Service Tech LLC is not responsible for any possible damages or injuries caused by the use or misuse of any information provided. ▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬
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[@acservicetechchannel]

-My Paperback, E-Book, Workbook, Quick Reference Cards: www.acservicetech.com/store -E-Book: play.google.com/store and search "AC Service Tech" -My Paperback and Quick Cards: www.amazon.com/shop/acservicetech -Support the Channel: www.patreon.com/acservicetech -Tool List: www.amazon.com/shop/acservicetech -Facebook posts every other day! facebook.com/acservicetech -Our Articles: www.acservicetech.com/articles -Our Quizzes: www.acservicetech.com/quizzes Related Videos: Frozen Evap Coil Troubleshooting: Liquid Line Restriction, Low Airflow, Low Charge! kzbin.info/www/bejne/rYvGpaOsgtmLg68 Explaining Superheat and Subcooling to Your Apprentice! kzbin.info/www/bejne/aISodZhmq52Jhrs Total Superheat Method! kzbin.info/www/bejne/qWqsYpSMqsyXobs Target Superheat Charging Chart! kzbin.info/www/bejne/mHqvanWogKiooMU Tools Used in the Video: Yellow Jacket Refrigerant Gauge Set amzn.to/2aenwTq Refrigerant hoses with valves amzn.to/2aBumVI Fieldpiece ST4 Dual Temp Meter amzn.to/2wc1ME3 Checking the Charge Tools: Yellow Jacket Refrigerant Gauge Set amzn.to/2aenwTq Refrigerant hoses with valves amzn.to/2aBumVI Yellow Jacket Gauge set & hoses amzn.to/2vLVkV9 Yellow Jacket 4 Port Manifold w Hoses amzn.to/2BkuGIq Digital Refrigerant Scale amzn.to/2b9oXYl Ratcheting Service Wrench amzn.to/2dGV4Nh FieldpieceSMAN380V Digital Manifold Set - amzn.to/2yqzBX6 FieldpieceSMAN480V Digital Manifold Set - amzn.to/2ytvGZL Fieldpiece SDP2 Digital Psychrometer - amzn.to/2nniMVR Testo 549 - amzn.to/2X0jJVj Testo 550 - amzn.to/3bIQvhS Testo 557 - amzn.to/2ylgeyw Compact Ball Valve for Refrigerant Hose amzn.to/2KUisW8 QuickDisconnect 90 for refrigerant hose amzn.to/2MMtVcg RectorSeal Bubble Gas Leak Detector amzn.to/2ckWACn Fieldpiece ST4 Dual Temp Meter amzn.to/2wc1ME3 Fieldpiece Bead K Type Temp Sensor amzn.to/2DBwKfs Fieldpiece Wet Bulb Temp Sensor amzn.to/2RRI7Tw Fieldpiece TC24 Temp Clamp amzn.to/2qHLyjZ Electrical Diagnosis Tools: UEI DL389 Multimeter amzn.to/2xAdaJf UEI DL479 Multimeter with temp sensor amzn.to/2jtsUbJ Magnet Jumpers- amzn.to/2PyKPQZ Alligator Jumpers- amzn.to/2PxqJXn Irwin Wire Stripper/Cutter/Crimper amzn.to/2dGTj2V Vacuum Tools: JB 6 CFM Vacuum Pump - amzn.to/2nqbvo8 CPS 4 CFM Vacuum Pump - amzn.to/2DxgPwY 1/4" Appion Valve Core Removal Tool - amzn.to/2uYr8WL 5/16" Appion Valve Core Removal Tool - amzn.to/2JHmfbP Appion Blue 3/8" to 1/4" Vacuum Hose - amzn.to/2uYlVyc Appion Red 3/8" to 1/4" Vacuum Hose - amzn.to/2uYg6Ro Yellow Jacket 1/4" by 1/4" 3’ hose - amzn.to/2umtcod Appion 1/4" by 1/4" and 3/8” hose - amzn.to/2Zyxzx9 Uniweld 1/4" by 1/4" 2’ hose - amzn.to/2GFov1Y CPS Vacuum Micron Gauge - amzn.to/2v1nM3O JB Vacuum Pump Oil - amzn.to/2mGrlXy Flaring Tools: Yellow Jacket Flaring Tool - amzn.to/2OBxGlM Spin Flaring Bits 1/4", 3/8", 1/2", 5/8", 3/4"- amzn.to/31BCs8Z Yellow Jacket Flaring Tool with Set Depth - amzn.to/2QIKsQH Yellow Jacket Torque Wrench - amzn.to/2NRR68Q Uniweld Swage and Flare Kit- amzn.to/2T55jyn Nylog - amzn.to/2MLJcch Ridgid Tubing Cutter - amzn.to/2DnjjR1 Wolverine Tube Reamer - amzn.to/2QGLyMV Swaging Tools: Manual Copper Tube Swage/Expander- amzn.to/2WRPa1M Spin Swaging Bits 1/4" to 7/8" for the Drill- amzn.to/2YQwwqS Uniweld Hydraulic Swaging Tool- amzn.to/2MlrI8m Uniweld Swage and Flare Kit- amzn.to/2T55jyn Uniweld Hammer Swage kit- amzn.to/2CzWMMU Uniweld 3/4" Hammer Swage- amzn.to/2CzXsSs Uniweld 7/8" Hammer Swage- amzn.to/2Mja5WE Uniweld Multi-Size Hammer Swage- amzn.to/2T3Cx1b Brazing Tools: Air Acetylene Torch setup - amzn.to/2aQalsb 15% Silver Brazing Rods - amzn.to/2gVLyLc Ameriflame Oxy Acetylene Torch Setup #1 &#2 Tip - amzn.to/2SRm3JF 40cu B Tank to 10cu MC Tank Acetylene Tank Fitting - amzn.to/2GxZZPi Nitrogen Regulator - amzn.to/2bXdR5f Uniweld NitroVue Flow Regulator - amzn.to/2GnsaAo Uniweld Nitrogen Flow Meter - amzn.to/2brvoBg Stay Brite #8 Silver Bearing Solder and Flux - amzn.to/2XIDJsY Aluminum Braze Rods - amzn.to/2IGNMu Refrigerant Leak Detection Tool: Accutrak VPE Ultrasonic Leak Detector amzn.to/2nFYKVe Shop through Amazon! Your Purchases through Amazon provide a means for channels such as mine to earn advertising fees from all purchases after clicking through. Prices are the same as normal.

[@timrob0420]

Does your book have any troubleshooting stuff on heat pumps in heat mode? I've come to some rheem units recently that have been having high head pressure issues in heat mode and it was not airflow as the indoor coil was clean, blower, and filter. Thank you

[@ronhanish]

this vid appears to be my exact current problem, ty

[@ronhanish]

this vid appears to be my exact current problem, ty, freeze after piston into evap. tubes ..suction pressure average 34. distcharte pr 177 avg. on r22 , looks like llr , i think filter dryer took a dump and is restricting. and 2 degree diff of filter dryer in in out

[@tylermartin799]

InstaBlaster.

[@ronhanish]

@@tylermartin799 IS THAT a sealer?

[@kaneamora7371]

I have worked hvac in an apartment complex for the past 5 years. I’ve never understood superheat and sub cooling until this video. This was a wonderful explanation.

[@Rocky1983511]

Hi,Craig, I am junior HVAC tech, whenever I have a question I search KZbin, your videos really help me to solve the problems. Your teaching videos really bringing me up to the next level.Thank you!

[@acservicetechchannel]

Thats awesome Rocky!

[@Ricoswavaey]

Wow you are the best I understand it very clearly now! It all makes sense i saw this same senario the other day but for a 410a system. The low side had 90psig and high side was 370psig although it was 95 degrees outside. Subcool temp was 8 degrees. I checked delta t and saw it had 12 degrees. So i tried adding like an ounce or 2 of 410a into the system and saw low side wasn’t going up in pressure, but then thought to myself this system isn’t low on charge based on subcool temp. So i stopped adding refrigerant. And looked at superheat as well and it was 44 degrees very high and knew something was up with the tvx. I also checked temperatures across the filter drier as well and saw no difference so i knew that wasn’t the problem. I then realized it was a bad txv not opening up and letting enough refrigerant into the evaporator coil. This is why we are techs we have to look at every aspect of the system. That’s how we diagnose these machines.

[@officerkrupke4966]

Craig, I know this is not relevant to this video, but since a lot of young hvac techs watch your videos, this post may help them with a very common misconception by some very experienced hvac people. I recently had a new unit installed by a company here in Florida, and was told the liquid line filter drier for my heat pump would be installed indoors near the evap. After the install, I looked for the drier but could not find one. I called the company, and they said some Manufacturers pre install them in outside condenser units. So I went outside and looked and could not see a filter. I did see what looked like a filter, but it was on the gas discharge line directly after the compressor, which from a google search, identified it as a compressor muffler. Hvac company owner came out and pointed at muffler and said that was the filter drier. Long story short, they sent tech out to install drier on my heat pump and the next day I checked, and it was a one directional drier. Oh Brother. Back out they came and swapped it out with a bi-directional drier. The tech pumped down the system for seven hours while he sat in his truck with the AC on. Who are these people? I just wanted a proper install. Instead I got the sweat box treatment. Didn't matter, I had a window unit in bedroom and binge watched Breaking Bad. lol.

[@renecuevas4128]

Yeah u need bi directional drier filter if in a heat pump HEAT will be used......but if just Cooling only you ll be ok

[@davidb2438]

I live in Florida. The techs I know are not qualified, it’s all OJT with little training. They usually are on the phone a lot getting help. It’s sad!

[@extremeair1199]

Sounds like greedy company owners hiring inexperienced techs.

[@nickledimez4012]

Excellent delivery and teachings from this channel. Purchase the book! I have been learning more from him than my classes.

[@acservicetechchannel]

Wow, thank you!

[@thebluelunarmonkey]

When you're at the point after seeing so many of Craig's videos when you can figure out hi/low pressure and superheat and subcooling by the title = sweet!

[@acservicetechchannel]

Thats fantastic! Thank you for your support

[@Damian-ir8gn]

This channel heaven sent.....

[@Ron-oe7hg]

I really enjoy your vids. Having being in this field for 30 years is proof that you can teach an old dog tricks he's forgotten lol.

[@suwajmarek]

Thanks!

[@ismackherbiehind]

Can you do a vid on bad compressor valves?

[@zesty2023]

So essentially if you have a liquid line restriction you're going to get low pressures in the evap coil due to the restrictions which is going to keep the refrigerant in that coil longer and give you a high superheat. Correct?

[@timrob0420]

Is there any way you could do some videos on diagnostic tips on heat pumps in heat mode? That would be kick ass

[@acservicetechchannel]

Thanks for letting me know what you would like to see!

[@VeryPersian]

Accurate information.

[@acservicetechchannel]

Glad you think so!

[@duramusmosley5530]

I had a call yesterday where the saturated temp on my low side went up but my suction line temp stayed at like 86 degrees. It was a 410A txv system.

[@duramusmosley5530]

I forgot to say as I added refrigerant all that happened

[@Froggability]

I guess it's a partial restriction at TXV, but with orifice or capillary restriction definitely see hp climb and LP drop, then cut out on either HP or LP - in my experience. With partial or complete blockage i'l Always flip the unit over to heating to observe the difference. (swap hoses!) Then *occasionally* a blockage will unblock. Go back to cooling and see. Other clues are unusual cold or frozen sections, eg Kinked line

[@La2venida]

What d I you mean switch hoses? Is there video about this? And your saying this might unblock restrictions?

[@acservicetechchannel]

_Do you have what it takes? Quizzes: www.acservicetech.com/quizzes -Our Articles with many descriptive pictures: www.acservicetech.com/articles -Facebook posts every other day! facebook.com/acservicetech

[@MRM-wp4gr]

If this was your ac system, and the unit seemed like it was cooling ok to you, would you just leave it alone? 2 deg over on subcooling does not seem like a serious enough problem to have to evacuate the system and visually check all the possible causes of what seems like a minor restriction?

[@NativeBowhunter1965]

This coming week, probably Tuesday I’ll be ordering the book bundle. Awesome videos and information in an easy to understand format. Quick question, does your book include complete wiring schematics for split systems? I’m really needing both low and high voltage wiring diagrams for residential systems. I’ve got a thermostat giving me a severe headache. Thank you in advance!! I’m referencing older 1980’s systems.

[@broncheemims8493]

Craig what do you think about blunon refrigerant replacement of R-22?

[@Albos11]

Great video as always. I have a question what can cause the high head pressure to jump up and down from from 300 to 400 psi?

[@bobjones2292]

I have the same problem

[@renecuevas4128]

Air in the system

[@keyronwiley2003]

Would an overcharge unit be the only reason why head pressure would be high when having a liquid line restriction? I had a restricted txv with high head pressure. I replaced txv and liquid dryer and that fixed the issue.

[@Gameboy_Steve]

Once again amazing video. Thank you.

[@acservicetechchannel]

Thank you for your support!!

[@jameylane1591]

How would a system behave if it had a restriction due to kinked outside copper lines? Would vent temps fluctuate?

[@CarlosMorales-vx2kv]

When do you charging the system … What temperature you put in the thermostat

[@douglasleonard987]

Would a joint/connection that has too much solder or a kink in the liquid line also be a liquid line restriction and cause high head pressure as well? Thanks!

[@terrywilliams4203]

I had the total opposite. I only had 4 to 5 degrees of subcooling (TXV). I added refrigerant and but it never changed.

[@lyrlyrplnts4hire]

We have a rheem that seems to have a restrictions but i can’t get the system to run long enough before it cuts out and goes into delay, so i can’t get proper levels or the time to even see where my pressures/temperatures level put

[@Swenser]

Hi. Thought I'd ask the question here about my car ac since you are the GOD of ac. My car ac works ok but seems to not cool as good as before. I've noticed the high side gauge needle at 185psi vibrates a bit whereas low side at 45 psi is still. Does the needle vibrations suggest anything or that's normal? Maybe weak compressor?

[@Sctronic209]

How does this effect micro channel? I had bad expansion valve restricting and starving the evaporator. 410a system seem to have rather high head and low suction.

[@theabsentmindedprofessor8357]

Excellent content, thank you!

[@aaronr164]

How do you tell if the filter drier before the evap is blocked or the TXV?

[@Gottextrastuff]

Check the liquid line temperature on both sides of the dryer. It should have less than a 5° difference

[@succa_repellent]

Thank you for your help!

[@Carlosperez-oe9no]

What about if has small ductwork, It's similar ?.

[@prettycureforever7102]

The filter drier at my house is really hot when you touch it and whenever liquid goes in it gets hot and it starts to boil is that a bad thing

[@tttota5421]

How to check subcooling in winter time ?

[@saviousmunaki709]

Thanks Mr Craig for the video it is a good one

[@acservicetechchannel]

Thank you for the support!!

[@saviousmunaki709]

all thanks to you ... do your compay hire foreign new tchnicians from college

[@82_KID]

Is it the same in a car AC system?

[@drsinai]

Hi, I have an R22 5 ton unit. It had lost all the Freon due to a hole in an aluminum tube within the condenser. My HVAC guy brazed the perforation with a copper tubing bypass, vacuumed the line and added fresh R22 but NEVER changed the dryer filter despite my request. He said it was unnecessary. After the charge, the system doesn't work. The high pressure reading is about 200 and there is barely a reading on the suction end ( about 5 ). He then added an extra 3 pounds of Freon- which made zero difference- overcharging the system. The system shuts off after running for 5 min or so. It is not cooling at all. He said it's probably because I have a "clog" in the line. The perforation was open the entire winter. Is the cause the dryer filter not having been replaced? I need your help and guidance. Thanks

[@stusmith3208]

Can over charging the system make a piston go bad or cause a restiction?

[@rickbraden4272]

Excellent.

[@proanswers]

evaluated a case study of a split goodman heatpump R41a unit that- used noninvasive MeasureQuick App data (has previous data year ago to compare) at 16.9 subcooling (factory sub cool 9). The refrigerant was stacking up at outdoor unit . To confirm restriction took temp measurements at the indoor coil before and after the TXV. Why did this restriction happen hypothsis #1 no drier filter at the indoor coil other #2 improper brazing allowed incondensibles noticed a 60% restriction of a bent suction line however dont think this was the cause of the high subcool#3 could not maintain cool temps 76 ambient 89. Usually the txv doesnt fail but can it be cleaned properly when you have a restriction in the indoor coil?

[@korgmanm6957]

Great channel! Quick question. What could be the problem if the needle in the High side gauge keeps rising on a small window unit until it trips overload. I charged unit by using manufacture specs. I was suspecting a restriction until I saw this video. Thank you in advance.

[@renecuevas4128]

Is easy to overcharge a window ac

[@001tracker001]

Return air, filter size, blower speed, txv or signs of a half assed replacement. Kind of like a split system that required 7 1/2 lbs but had 22 lbs of charge causing the compressor to bypass. 🤯

[@stevegibson6755]

If I recoved the freon , cleaned out the piston then ran a vac on it would that clear the restriction. How else can I clear the restriction

[@MrG-hm7xs]

Why does the high head pressure trip when the high pressure drops what causes that....

[@JaspreetSingh-te7jt]

Hi actually I have a problem with my ac it’s cooling less got it checked from tech seems he didn’t caught the problem I m mentioning the reading he took and he decided in few minutes that compression faulty ,after watching this video I found my problem looks like same readings r on Goodman R410 head pr 250/suction Pr 100 he wrote 50deg SH and 14 Deg idk what it is maybe sub cooling I have called him again for expansion valve seems he wants me to change the whole ac unit as he say the compressor is drawing low amps 6amps only ac blows cold air but runs continuously what can be the cause as I can’t afford to change whole unit it’s only 4 years old but compressor is 6yrs old out of Warranty

[@renecuevas4128]

Sounds undercharge

[@mariodiaz6438]

How about normal suction pressure s but the liquid line it's 300 psi & sub cooing it's 43

[@jericosha2842]

If you aren't able to absorb much heat, then how is there so much superheat? If the coil is so cold, then why is delta T so low? I am assuming that's because the coil is probably freezing and restricting air flow, but then why is superheat still so large? You did think if it's that cold with little airflow you would have way less superheat.

[@zekenzy6486]

Great Video. Thank you for sharing ^_^. Happy Weekend

[@acservicetechchannel]

Thank you! You too! Love the support.

[@kennethlobo4420]

Craig lets presume that i do have a liquid line restriction,and i have also charged refrigerant to raise vapour temp above 32 degrees,in this case how do i sort out this problem? Do i need to first recover the extra refrgerant and then proceed to find the liquid line restriction? Pls advice how U would go about it.

[@acservicetechchannel]

Measure for a temp drop across the filter drier first as shown in the video to see if thats the prob. If not, figure on replacing the TXV, screens, and filter drier. the screens should come with the TXV. If you have a piston, figure checking the piston and the screens for a clog and replace the filter drier. This is all done after a pump down or shuttign the valves to the outdoor unit and recovering the rest of the refrigerant. You could also recover all the refrigerant and break the vacuum with the total amount of refrigerant needed for the system after fixing or replacing the problem, thanks!

[@semmeh4918]

Please if you can made a proccess of charging mini split unitis, when he is undercharge how to detect and how to charge without recovery refrigerant from the sistem, by only adding

[@kingb468]

Very informative.

[@acservicetechchannel]

Glad it was helpful!

[@elfig1993]

I have a unit that is 410-A and my pressure in my high line is very low and my subcooling is to high, why this can happen

[@District0fMisery]

Great video 🤘

[@voro5102]

Gold

[@condorman26]

I had a unit do something similar. Subcool was 12. 190 head pressure. Suction. Pressure 54 and superheat 26. And vsat was 26. Does thins sound like a liquid restriction to you? Thanks

[@markang4675]

What is the problem. Refrigerant at 120 but still icing

[@michaelanthony1593]

What if the psi drops to 0psi on the suction line when I turn the unit on? Stable pressures when the unit is off. I have a fixed orifice 410a unit.

[@markhoffmann5941]

OK, i started up a brand new 3 ton Goodman condensing unit with an 11 year old up-flow 3 ton evap coil with TXV... new clean filter... OK air flow... delta across the coil 15 degrees,, entering at 77 degrees; leaving at 62 degrees... low side at 150 psi, high side at 251 psi approx 2 degrees of sub-cooling and about 2 degrees of super-heat. R-410a system OSA @ approximately 82 degrees... I'm thinking the TXV bulb is failing or the valve is sticking open a bit...The 230 volt scroll compressors RLA is 14 amps and i was measuring around 9 to 10 amps... any other ideas besides a bad TXV ??? the new condensing unit has a factory installed liquid line filter dryer...

[@toli0968]

410a system very high superheat over 50 low suction. 112psi ...head pressure 405 psi but 0 degree sub cooling...... readings after I cleaned condenser.....???? undercharged system with a restriction/txv??

[@GreyRockOne]

Good info, thanks. Is a liquid line restriction common? On average when can one be expected (if ever)

[@TheNYgolfer]

They mostly occur in the metering device (capillary tube, expansion valve, piston ) and filter drier. not in the line itself

[@swagg8754]

Was gonna check the charge on my ac unit today(R22 capillary system), but had 0 pressure on my high side pressure. Saturated temp was 40° across the coil and the line temp was almost 100°. The strange thing is that at my return was about 70° and at the nearest register was 52.5° so the temp drop across was good. Just can't figure why I got 0 high side. Can you tell me what the possible problem could be? I even used 2 different manifolds and got the same result. I thought it could be a bad Schrader valve blocking me out of the pressure due to the fact that when I went to disconnect my hose from the liquid line service port, I didn't get hardly and spray off??

[@davidb2438]

I would suspect bad schraeder

[@hvacguy11]

I liked the video during the intro commercial just saying lol

[@acservicetechchannel]

Thank you

[@Harrypizzalover]

I have I going now I installed 3 ton Arcoaire 3 ton split system ac only ,put on existing Goodman furnace system is running a very low suction r410a about 100 psi , high side is good and sub cooling is 10f, NO SUPERHEAT suction is always a degeee colder than the evaporator temp , I’m going to see if I got a restriction somewhere. Any ideas

[@edwardmannar9307]

hi love your videos. question on a normal operating system charged correctly how is subcooling affected on a system with longer lineset? 50 to 75 feet. for example: would subcooling be higher than rule of thumb 10 degrees to make up for additional Freon for lineset?

[@meverickjnphilip9885]

I am trying to buy the books but cant select them to put in the cart

[@acservicetechchannel]

Meverick, try refreshing the page before clicking add to cart. We make updates on the website but it is possible that your browser is holding onto the old version of the page possibly. I apologize for any inconvenience. I don't know why that is. We also have our products at www.amazon.com/shop/acservicetech and thank you for letting me know and thanks for your interest!

[@meverickjnphilip9885]

@@acservicetechchannel I got it already

[@TOMTOM-nh3nl]

Thank You

[@acservicetechchannel]

Thank you for your support!

[@mematyi]

Great video! Very helpful, thanks for the share! I'd have a question: What if we do not have a target superheat written on the unit, and/or do not have liquid line service port at all? Many of the new split air conditioner units here in Europe are now using Electronic Expansion Valves either alone, or combined with a capillary tube, which I would consider similar to a TXV in workings. How can I determine if it is charged correctly? IMHO the old trick with checking the superheat on the vapor line does not work any more, or is it? Fortunately I never had a leaking R32 unit to service, but it will happen eventually.

[@Jeff-Lawrence]

I noticed your wearing the black nitrile gloves. Do you usually wear those when hooking up refrigerant hoses or do you recommend a a different type? And if so what gloves would you recommend?

[@cu27rotary70]

Do you use probes? Low loss fitting? Either will allow you to wear any kind of gloves.

[@craigmarshall40]

I am one of your Patreon’s if you Can answer my question that would be a big help I have a system r410a with a piston that on hot days that are over 95 outside the low side is at 140to150 Hi side will go from 400 to over 500 and back and forth if I remember correctly the suction line is 63 degrees outdoor 7 years old and is clean and in good shape clean filter and indoor coil is clean it does have a filter on the high side by the piston . The out fan is blowing good but very hot air off of it if I take a water hose and hose out door unit the high side pressure will come down to 350 psi it always blows Cold air inside the house but intermittently the unit will shut down due to too high pressure thanks

[@acservicetechchannel]

It sounds like there could air in the system mixed with the refrigerant possibly. What seer, indoor wb temp and delta t? You could shut the unit off and let it equalize and compare the sat temp to the surrounding air temp. If the sat temp is higher, the system has air in it. Has the outdoor fan and/or motor been replaced before? Please respond back at [e-mail] to make sure that I get your message back. Sometimes I miss them in the you8tube comments, thanks!

[@sraeg]

Hi to All. I have the following scenario and will appreciate your feedback. I just had installed a new AC+furnace system. At the evaporator coil, the tech. brazed the liquid line which had to bend it like 45degrees to connect to the evaporator coil. The issue with the bended 3/8" copper pipe is that, at the center where the pipe changes direction, the 3/8" pipe is flattened. Would anyone tell me please if this is bad for the system. And what technical wording should I tell the technician to force him to brace a new piece of 3/8" pipe? Thank you

[@dalegribble1258]

Depends how kinked the line is, if it’s a lot it could be bad but if the system runs properly and the kink is not that bad then it’s really just cosmetic

[@joemarortiz130]

This happened to me today

[@ShootieMcShoot]

Quick question, I have some gauges that are r134a, 404a, and 407a can I switch out the gauges and for some 410a and r22 but keep the same manifold?

[@samuelvalenzuela4541]

Yes

[@doncocorote1]

I checked a r22 system Pistón and the suction line pressure was 8psi and the liquid line 140psi. You think it can be a line restriction? Thanks hope you can answer

[@samuelvalenzuela4541]

Could be a line restriction or a refrigerant leak so it's low on refrigerant

[@paulrozinski1488]

In EVERY video that he does with a temperature probe, he always uses the wire type instead of the clamp on probe. Does that mean that the clamps are not reliable??? I have mixed feelings about them myself. I’ve seen too many fluctuations with the clamp probe ( even a Fieldpiece brand ) . Peoples thoughts are welcome. Thanks

[@Gottextrastuff]

Try using a piece of sand cloth to clean the pipe to get better contact.

[@canman1088]

Really to be accurate electrical tape will not do because you are still reading a little ambiant temperature. Using a piece of armaflex taped with electrical tape will be more accurate with those style temperature probes.

[@vijayvira8animakers189]

Sir give me a one solution to over pressure The unit

[@Gottextrastuff]

Outdoor coil dirty. I see that a lot.

[@upstaterelicsandescapades1599]

Bad txv....or.....too large of flowrater piston....or strainer is plugged.....or txv has locked wide open......or txv strainer is plugged. Take temp readings at in and exit of piston / txv.....you will locate your problem,that is, if there is not a restricted condenser.

[@ericbeauvais6017]

What happens when the high pressure line is very cold

[@itz_mohittt869]

Sir how to flush underground pipes without nitrogen should i use r32 gass for flushing pls answer sir

[@acoustic4037]

Treat yourself and get a fieldpiece sman. Clamps and having the numbers in front of you real time (you can see when contamination runs through) beats thermocouples and looking up values and doing the math repeatedly. Especially nice to see as you weigh in a charge on a low system.

[@firstlast1732]

Out of all the guys on here this guy is the most difficult to understand

[@JohnDoeEagle1]

His slender scrawny build and wearing latex doctors gloves kinda discredits him to me after doing this 21 years. Nobody real is that skinny...how do they lift and haul around units and concrete slabs. Second if you are worried about a little oil, grease or dirt on your hands you have never seen a real HVAC techs hands in your life. They are heavily callused, cut up and your skin is like shoe leather. It's a joke really if you know yourself what to look for. I never once worried about my hands while crawling through a crawlspace or been down in someones basement with a busted sewer pipe or they let their dogs and cats take a dump and urinate on the floor with flies all flying around. ~John~

[@WeWander2]

Clogged dryer. Humm

[@roygerson694]

You showed us a unit with a liquid line restriction but you didn't tell us what the liquid liner strict ended up being

[@AngelTorres-tk2nw]

My mother said that you are the Man & I am the child.

[@nickledimez4012]

Excellent delivery and teachings from this channel. Purchase the book! I have been learning more from him than my classes.

[@acservicetechchannel]

Wow, thank you!