The E-Book and Paperback: www.acservicetech.com/the-book Tool List- www.amazon.com/shop/acservicetech Support the Channel- www.patreon.com/acservicetech For those that are looking for the tools used in the videos: (Linked Below) Appion Valve Core Removal Tool amzn.to/2uYr8WL RectorSeal Bubble Gas Leak Detector - amzn.to/2ckWACn 25 Valve Cores - amzn.to/2L37UJU 25 ¼” Brass Port Caps with rubber O-rings - amzn.to/2GIOdD2 Brass Valve Core Tool which holds 3 valve cores - amzn.to/2GFEbm2 Valve Core Torque Wrench - amzn.to/2GHiLoD Locking Cap Universal Lock/Unlock Tool - amzn.to/2GGAoVp Locking caps - amzn.to/2GFXZ8A Ratcheting Service Wrench amzn.to/2dGV4Nh Yellow Jacket Sealright 90 Coupler- amzn.to/2LsU1V7 Yellow Jacket 1pk Compact Ball Valve- amzn.to/2uXdF18 Yellow Jacket 3pk Compact Ball Valve- amzn.to/2AiKfQe Thumb Screw Valve Core Depressor with Backseat- amzn.to/2mR0sCL UEI DL479 Multimeter with temp sensor amzn.to/2jtsUbJ 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 Accutrak VPE Ultrasonic Leak Detector amzn.to/2nFYKVe Accutrak VPE-GN Ultrasonic Leak Detector amzn.to/2Zy4IZP FieldpieceSMAN360 Digital Manifold Set amzn.to/2BdoaD4 FieldpieceSMAN460 Digital Manifold Set amzn.to/2nB4Fe6 Ultrasonic Leak Detector with Headphones- amzn.to/2B2cRO3 Compact Ball Valve for Refrigerant Hose amzn.to/2KUisW8 QuickDisconnect 90 for refrigerant hose amzn.to/2MMtVcg JB 6 CFM Vacuum Pump amzn.to/2nqbvo8 Appion Blue 3/8" to 1/4" Vacuum Hose amzn.to/2uYlVyc Appion Red 3/8" to 1/4" Vacuum Hose amzn.to/2uYg6Ro Appion Valve Core Removal Tool amzn.to/2uYr8WL Yellow Jacket 1/4" by 1/4" hose amzn.to/2umtcod CPS Vacuum Micron Gauge amzn.to/2v1nM3O Supco Vacuum Micron Gauge amzn.to/2v1JRiA RectorSeal Bubble Gas Leak Detector amzn.to/2ckWACn Magnet Jumpers- amzn.to/2PyKPQZ Alligator Jumpers- amzn.to/2PxqJXn 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 UEI DL389 Multimeter amzn.to/2xAdaJf Air Acetylene Torch setup amzn.to/2aQalsb 15% Silver Brazing Rods amzn.to/2gVLyLc Nitrogen Regulator amzn.to/2bXdR5f Nitrogen Flow Meter amzn.to/2brvoBg Other tool links can be found in the video description section. 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- www.amazon.com/shop/acservicetech
I was guilty of beer can cold charging for my first 2 or 3 years of doing air conditioning. Its the way the guy who got me into the field taught me..... Just add 30 psi over the outside temp, lol. Then.....I went to school. I swear to God some "techs" who have been in business for 20 years have no idea what they are doing to people. Your video is spot on.
Excellent video, I wasn't aware that TXV metering uses sub cooling reading for charging and pistons/fixed metering used super heating for charging. Lessons learned thanks.
Thank you for your kind words! I'm glad you found the video informative. Understanding the different charging methods for TXV metering and fixed metering systems is crucial for proper HVAC system performance!
@@acservicetechchannel very nice manual! I've read through a few chapters and for me personally is a nice refresher but gained some nice insight on other things too! I wish I could give a full review but I'm a pretty busy these days and I read about as fast as a snail moves. Lol! But nice easy read and nicely detailed illustrations. I honestly have little experience with "refrigeration" per say so I'm looking forward to more insight in that area. But very nicely done, great material covered, the manual construction is very nice as well! I like the spiral bound so it's easy to flip open to a specific page and have it stay there. The paper is very nice quality as well. So I'm very pleased with this manual! Thank you for all the video tutorials and putting together such a nice book. Very worth the money. Especially with all the video teachings you've done as well. Extremely happy to support what you do! Thanks again and keep me posted with anything new!
Excellent video and very thorough explanation. Good job mate! One observation here: Based on your readings here I get recommended Superheat of 19 (you could have noted this in video) and you have it right for the unit at 13 degrees. For this (lower superheat than recommended = excess charge), ideally the charge should be removed as it is in excess. As you already confirmed this with subcooling of 15.5 degrees and that you have 3.5 degrees higher than rated subcooling of 12. In another words, the higher subcooling is now confirming a slightly excess charge in the system (And you're stating this in the video too). According to my calculations, the superheat is not correct; ideal for these readings is 19.
@@acservicetechchannel thanks for replying. I'm thinking that by reducing the charge pressure would decrease. Hence, suction line temperature based on decreased pressure will be lowered than before and thus by increasing the difference to suction pipe line temperature. And we'll get higher Superheat reading than before and then also lower Subcooling more towards normally rated, which is 12 for this unit. Please correct me if this is incorrect.
@@tfinavia01 Like I mentioned before, the txv will control the superheat so as long as you have at least 4 degrees of subcooling the txv will hold that sat temp and superheat at the same level on the suction side. You can't get that suction side to move up or down with a slight reduction or addition of charge, thanks! I describe all these topics in the paperback/ebook I put out on the website acservicetech.com thanks!
Have no idea what your saying ....but subscribed and starting your videos from day 1...should binge watch and catch up in no time...and will look into the book
Ha ha. It all comes with time. Thanks. Let me know if you have any questions as you move through them. Start with the hvac basics playlist maybe, thanks!
That is correct educational stuff on that method for sure. AWESOME ONCE AGAIN. Thank you and I will check out your website and get your book. Thank you HVAC ON!!!
Are condenser coils clean? Would it matter... filter good? Just asking. A big fan. Learned a lot over the years. I re-watch bids just to remind me and put my fellow techs on to u. Keep it up. Gonna order ya books soon. Again big fan
Thats awesome to hear! Filter clean and airflow roughly 350-425 cfm per 12,000 BTU's would affect the checking of the charge and system capacity. We put the effects in the troubleshooting cards and in the book, thanks!
and if by chance you look at a system new to you, has a TXV bulb just dangling unattached to the suction line, it's been controlling flow by the warmer air temp, not the cooler suction line temp. So it'll be requiring a higher pressure to open up the valve. hope i worded that right!
The bulb would be dangling in a warmer area and the warmer temp will cause the TXV to open more and allow more refrigerant into the evaporator coil. The actual superheat will be very low for the system, thanks!
@@acservicetechchannel i believe this was an old gf's unit. main problem was air flow, spent the day cleaning everything. still thinking of the hanging bulb. whether after cleaning, it would ice up or just not move heat, might depend on compressor specs? regardless, I think the compressor would overheat being robbed of cool vapor... ?
@@acservicetechchannel Page 177! Craig I am glad it is only the 2nd day of looking thru your book that I read the Rating Plate label very closely on the condenser graphic. Shows the required subcooling etc. Nearing 50 years old I'm glad it took me 2 days and not 2 or 20 years to finally read the fine print :)
You should always check superheat at the bulb near the evap. The Bulb opens the TX valve and maintains superheat. Thats a better location to measure at the bulb but you can still measure at your line at the compressor. It's more accurate at Evap. The Gauge on the lowside is giving you the pressure of your evap in other word SSP ( Saturated Suction Pressure) use the PT Chart to get your SST Line - SST = Superheat Or Line - Gauge temp. For Subcooling Most Residential condenser have a condenser split of 30 degrees and you have 80F OAT( Outdoor Air Temperature. Another way to check what your condenser should be on a day like 80F Condensing split: 30+80(OAT)= 110F That a rough estimate on what your condensensing temperature should be SCT ( Saturated Condensing Temperature). If its higher than 110F on 80F day. Could mean dirty coil possibly the unit is over charged ETC Most A/C have a 10Fdegree subcooling Gauge110F - line100= 10degree subcooling Or even check your delta T. Return temp and Supply temp. Return temp at 72F supply 52F thats normal. If you had 72F return and 62F supply something definitely wrong. 72-52= 20 Delta T. Thats good
The reason we check total superheat at the compressor is because there is no port at the evap coil and techs don't take the time to remove the cover plate, find where the sat state will be at and tape a sensor there temporarily. There is a port at the outdoor unit and it is essential that we check if there is total superheat present there for the compressor's safety. I wrote full articles on our website about these topics at www.acservicetech.com/articles thanks Tmac 01!
@@acservicetechchannel i get that 100%. Also next time in your video you should also do Pressure/Enthalpy chart and psychrometric charts after you calculate your subcooling and superheat. Include that next time. Good video
Any recommendations for inexpensive thermostat I can use to measure line temps? Can I use a probed thermostat like Klein ET05 by touching the probe to the lines or do I need clamps? It appears you are using Fieldpiece ST4 in the video with the included leads (no clamps).
I been watching alot of ur vid! Great work👏..hopefully u can make a commercial fridge & freezer book. I don't see good vids out there and you my friend make AWESOME vids. Thanks so much! Much ❤ from san diego! LIKED & SUSCRIBED FOESHHEEZZZY!
Great video! Let’s say the TXV is malfunctioning in the close position, would the Evaporator start freezing? What if I think that is low on Refrigerant, and I add Refrigerant; how would that reflect on my pressures or superheat and subcooling?
Hey Abner, yes if the txv was mainly closed but letting a small amount of refrigerant through, the sat temp would be low and the coil would freeze. A liquid line restriction would be high superheat and normal to high subcooling. If you added refrigerant, it will just increase subcooling and the superheat will remain about the same, thanks!
Good to know. Now, since this system uses R-410A, you state to check both the superheat and the sub-cooling temperatures to see if they are correct. If this method ONLY good for R-410A refrigerant or should you use this method to check earlier systems using R-22 refrigerant? Keep your videos coming. Thanks
Thanks Steven, total superheat and subcooling need to be checked on all ac units regardless if they have r22 r410a or another refrigerant, thanks Dennis, and John!
hi, when standing pressures don't equalized (unit off) . does this mean there's a restriction? (i.e. R410A low side is around 150psig and high side is around 300psig). thank you.
It could just be a hard shut off TXV. If there was a restriction that wouldn't let the system equalize then the system would not work at all and it would break the compressor. Once the compressor turns on and pressurizes the line, the txv opens and allows refrigerant through, thanks!
Its mainly about air conditioning but the preparation steps are the same. I also talk about the txv, three position service valves, and the receiver, thanks!
@@kengardner5097 for a non txv system, a derived taget superheat is required. review your studies of basic psycometric charts. start with a NATE refresher.
Great video...I have learned a considerable amount from your content. I am not a technician but a home owner with refrigerated air. However, I am seriously considering going into the field. Here is my dilemma. I would not be able to attend my local community college until spring of 2020 due to other commitments. Is there any other way to get the HVAC education in order to be certified in Texas. I have looked into online programs but have not been able to find any substantive reviews in regards to this type of HVAC training. I have considered Ron Walker's HVAC training solutions (he is on youtube as well). What would you or your viewers suggest? Should I wait and go through community college or is the online route a legitimate option? I would appreciate your input. I will continue to follow you and definitely will be purchasing you book.
J K I registered an online HVACR program at the beginning of this year ( 01/01/2019) and graduated in April. Got EPA universal certification in May. Bought a lot of tools and played on my own AC. I have learned a lot from UA-cam videos. With Joblink smart probe kit I offer free diagnosis to my friends AC and walk in coolers( restaurant owners). Learned a lot so far!
JK, There are lots of great learning sources available cheap! Check out hvacrschool.com. Craig’s book is great. Lots of great used “cheap” books at Amazon.com. I used “Moderm Refrigeration and Air Conditioning “. NATE study manuals are cheap. EPA section 608 study guides were available free. Or you may purchase reasonably priced. Study at you own pace and for cheap. I’ve been doing the studying and testing as a hobby. Good luck 👍🏽. Enjoy
@@UltraHydrophobiccoat, if you don't mind me asking, what online program did you pursue and what was the cost? I have also learned a great deal from youtube as well and have used that information to fix my AC a couple of times. However, I have not started to build my tool kit as of yet.
@@chuckdearruda6271 thanks for the information. I took a look at the hvacrshool.com. That seems to be geared towards individuals that are already techs. However, it definitely seems to have information I would need once I became a tech. Also, I appreciate the other information on study materials. What are your feelings about using an online program?
JK, There is sooooo much great info Free online. ua-cam.com/video/15ZrpM41enE/v-deo.html Start here then Google or search within UA-cam (HVAC). (Stephen reardon) (Grayfurnaceman) Dr Z), Study what you want, when you want,,,, Free! Enjoy the journey You can’t go wrong with teachers like Bryan Orr and Jim Bergmann. Checkout (free) educational stuff at the TruTechTools website too. When in doubt, Google
Living in Texas but you say Cape May County did you originally start in Philly cause you seem familiar even though dont get to see you in the videos and yes your videos are very informative
you made a mistake at 5:19 mark you said because our total super heat was 3.5 higher than our target we should recover when you should of said ADD refrigerant. also ive read its ok if its a 5 degree difference because you never want to add charge for the risk of overcharging and damaging the compressor.
I am in my last semester of HVAC/R and I am working on a condenser unit (w/o heat pump) that has 2 compressors, the contactors are labeled HI and LO. How do I check the charge on it? I am about 90% sure it is low on charge because I have a high super heat (25+), low suction pressure (105) and low sub cool (3.8 - 4.5).
Craig, Where did you get the range of 10-14 degrees of superheat for the Txv as the correct superheat for the system? I know the target subcooling is on the data plate but where is that superheat range from? Is that from the outdoor temp/in door wb temp chart?
Hi! I noticed that the superheat and subcooling are almost equal. Is this an indication of a properly charged system? I'm planning to service my car AC and there is no info about how much (in weight) should the charge be. Is it safe to assume that the subcooling should be around 11 - 14 degrees? The system uses TXV btw. thanks!
Hello I have an air conditioner , i want to know what does mean by design pressure HI 446 PSIG LO 236 PSIG which wrote in the out door unit ? Most of A/C units write in the nameplates low pressure and high pressure in Kpa but i don't know what they mean by that .
When looking at the manual for my condenser (American Standard 2-stage unloading scroll), it says to increase the subcooling target for lift and lineset length. My evaporator coil is in the attic above the 3rd floor, so it has a very long lineset with 3 floors worth of lift, which is at the max limit for that model. So that would be the 9 degree default on the plate/manual plus 3 degrees for lift and length, for a total of 12 degrees subcooling. When techs come and check the charge, they only look at the plate which says 9 degrees +/- 3 degrees. So if it was at 9 degrees, should they bring it back up to 12 degrees? And would the new MAX subcooling still be 12? Or would the new MAX be 15?
Can you explain it to me please why other compressors have the sum of 2 pins equivalent to 3 pin and my has all the same just want to understand it fully please
I gotta question, maybe someone can answer. Sub-cooling is saturated temp minus actual temp and super heat is actual temp minus saturated temp. If you're measuring sub-cooling, then why not do both the same way as superheat such that sub-cooling gets you a negative number, like -13°F instead of +13°F sub-cooling? Then using proper math you can see the temperatures increasing and decreasing as it actually is.
You just blew my mind! Kind of makes sense since the liquid temp exiting the condenser should be about 10 degrees cooler than the saturated refrigerant in the condenser. You are going to turn the HVAC industry upside down with that kind of thinking. What I don't understand is how we take pressure measurement at the service port location and extrapolate that same pressures to the middle of condenser and evaporator. Are the P/T charts already adjusted for this difference in Pressure vs Temp?
Tommy, at what temperature does water freeze? If your evaporator coil is at or below 32 degrees and there is any humidity in the space being cooled it will begin to form frost on the coil and begin to restrict airflow thru the coil.
If the sat temp is below 32 degrees, the coil will freeze the humidity crossing the coil. This could be due to a low refrigerant charge, liquid line restriction or low airflow, thanks!
The txv by design is continuously adjusting the superheat within a certain range......so that does not allow you to accurately measure the actual charge of the system(via superheat). The system could be over/undercharged and the txv would be trying to compensate for the current charge state. Why NOT check the subcooling?!?!?
@@ruftime So then why do I see so many installers doing this in my company? Also, the AC systems seem to work okay and they are not hooking up to the high pressure part.
Jackson, I’m guessing the culture of your company allows/encourages this practice. I’m sure most of the time it gets the job done, just like those automotive A/C recharge cans with one gauge!?!? But ultimately everyone is losing out, especially the technician if he wants to get better. Fully hooking up to systems will give you an ever growing perspective on what to expect and how to diagnose BEFORE wasting your time recharging. It’s not the wrong way, but it’s not right either:-)
Hey Jackson, I would not bust the higher techs chops too much since they are higher in the company than you but when you are out on your own, you can do the procedures properly and check both superheat and subcooling. This will give you a real glimpse into what is happening in the system and they are the proper charging method, thanks Canyon Racer!
Love your content but you talk so fast I have a hard time keeping up and it hurts my head lol. Any other channels you can maybe recommend for someone slow like me?
That is the main product we sell in order to create all the free training videos. Its ok and just watch the free videos and learn as much as you can, thanks!
The E-Book and Paperback: www.acservicetech.com/the-book
Tool List- www.amazon.com/shop/acservicetech
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For those that are looking for the tools used in the videos: (Linked Below)
Appion Valve Core Removal Tool amzn.to/2uYr8WL
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25 ¼” Brass Port Caps with rubber O-rings - amzn.to/2GIOdD2
Brass Valve Core Tool which holds 3 valve cores - amzn.to/2GFEbm2
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Other tool links can be found in the video description section.
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- www.amazon.com/shop/acservicetech
Thank you
I was guilty of beer can cold charging for my first 2 or 3 years of doing air conditioning.
Its the way the guy who got me into the field taught me.....
Just add 30 psi over the outside temp, lol.
Then.....I went to school. I swear to God some "techs" who have been in business for 20 years have no idea what they are doing to people.
Your video is spot on.
Sounds like a lot of professions. Reminds me of often times over the years informing someone " maybe they have been doing it wrong for 30 years "
i have spent my entire weekend watching your videos. I can't wait to go back to work and keep learning applying.
Thanks AC Dad!
You got this!
Excellent video, I wasn't aware that TXV metering uses sub cooling reading for charging and pistons/fixed metering used super heating for charging. Lessons learned thanks.
Thank you for your kind words! I'm glad you found the video informative. Understanding the different charging methods for TXV metering and fixed metering systems is crucial for proper HVAC system performance!
Just ordered your book now! Been in HVAC for 20 years. Always enjoy your instructional videos and looking forward to learning more from your manual!
Thanks a lot Kelly! Let me know what you think of it after reading, thanks!
@@acservicetechchannel very nice manual! I've read through a few chapters and for me personally is a nice refresher but gained some nice insight on other things too! I wish I could give a full review but I'm a pretty busy these days and I read about as fast as a snail moves. Lol!
But nice easy read and nicely detailed illustrations. I honestly have little experience with "refrigeration" per say so I'm looking forward to more insight in that area.
But very nicely done, great material covered, the manual construction is very nice as well! I like the spiral bound so it's easy to flip open to a specific page and have it stay there. The paper is very nice quality as well.
So I'm very pleased with this manual! Thank you for all the video tutorials and putting together such a nice book. Very worth the money. Especially with all the video teachings you've done as well. Extremely happy to support what you do!
Thanks again and keep me posted with anything new!
Have you actually removed the lenses from your gauges to make the dials more visible to the camera? What a guy!
Absolutely, thanks for noticing ha ha!
@@acservicetechchannel It makes a difference for sure. I'm always amazed by your attention to HVAC details but this is truly special.
Thank you very much James!
Another great teaching video -- as usual! Thank you and please keep posting.
Thanks Ma Ma, glad to help!
bump to 2023 good stuff man
I’m buying his book right now!!
Thanks and I would love to hear what you think of it after reading!
Excellent video and very thorough explanation. Good job mate! One observation here: Based on your readings here I get recommended Superheat of 19 (you could have noted this in video) and you have it right for the unit at 13 degrees. For this (lower superheat than recommended = excess charge), ideally the charge should be removed as it is in excess. As you already confirmed this with subcooling of 15.5 degrees and that you have 3.5 degrees higher than rated subcooling of 12. In another words, the higher subcooling is now confirming a slightly excess charge in the system (And you're stating this in the video too). According to my calculations, the superheat is not correct; ideal for these readings is 19.
Tushar, this system has a txv which controls superheat so adjusting the charge will not change the superheat like a fixed orifice system, thanks!
@@acservicetechchannel thanks for replying. I'm thinking that by reducing the charge pressure would decrease. Hence, suction line temperature based on decreased pressure will be lowered than before and thus by increasing the difference to suction pipe line temperature. And we'll get higher Superheat reading than before and then also lower Subcooling more towards normally rated, which is 12 for this unit. Please correct me if this is incorrect.
@@tfinavia01 Like I mentioned before, the txv will control the superheat so as long as you have at least 4 degrees of subcooling the txv will hold that sat temp and superheat at the same level on the suction side. You can't get that suction side to move up or down with a slight reduction or addition of charge, thanks! I describe all these topics in the paperback/ebook I put out on the website acservicetech.com thanks!
Have no idea what your saying ....but subscribed and starting your videos from day 1...should binge watch and catch up in no time...and will look into the book
Ha ha. It all comes with time. Thanks. Let me know if you have any questions as you move through them. Start with the hvac basics playlist maybe, thanks!
That is correct educational stuff on that method for sure. AWESOME ONCE AGAIN. Thank you and I will check out your website and get your book. Thank you HVAC ON!!!
Sounds great, thanks Ray Ray!
Knowledge is everything.
100% thanks!
Great video very helpful keep posting bro. Thanks for another great video keep up the good work
Glad to help Terry!
You guys are amazing, love it.
Thank you for your support!
Great info Craig ...
Thanks Eddy!
Great video..great information...this guy is on point 👍
Thank you
Thank you!!!!
Great info, thanks for sharing
Glad to help!
Are condenser coils clean? Would it matter... filter good? Just asking. A big fan. Learned a lot over the years. I re-watch bids just to remind me and put my fellow techs on to u. Keep it up. Gonna order ya books soon. Again big fan
Thats awesome to hear! Filter clean and airflow roughly 350-425 cfm per 12,000 BTU's would affect the checking of the charge and system capacity. We put the effects in the troubleshooting cards and in the book, thanks!
I've noticed it is so easy to overcharge 410A when you're wanting to increase temp by 4-5 degrees.
Great info!
Thank you, glad to help!
Good stuff Sensei 👍
Thanks a lot Tom! Always glad to help!
Good job. TY
Thanks Kenneth!
and if by chance you look at a system new to you, has a TXV bulb just dangling unattached to the suction line, it's been controlling flow by the warmer air temp, not the cooler suction line temp. So it'll be requiring a higher pressure to open up the valve. hope i worded that right!
The bulb would be dangling in a warmer area and the warmer temp will cause the TXV to open more and allow more refrigerant into the evaporator coil. The actual superheat will be very low for the system, thanks!
@@acservicetechchannel i believe this was an old gf's unit. main problem was air flow, spent the day cleaning everything. still thinking of the hanging bulb. whether after cleaning, it would ice up or just not move heat, might depend on compressor specs? regardless, I think the compressor would overheat being robbed of cool vapor... ?
@@acservicetechchannel Page 177! Craig I am glad it is only the 2nd day of looking thru your book that I read the Rating Plate label very closely on the condenser graphic. Shows the required subcooling etc. Nearing 50 years old I'm glad it took me 2 days and not 2 or 20 years to finally read the fine print :)
Awesome channel awesome book
Big time 🙏🙏🙏
Thank you very much!!!
You should always check superheat at the bulb near the evap. The Bulb opens the TX valve and maintains superheat. Thats a better location to measure at the bulb but you can still measure at your line at the compressor. It's more accurate at Evap. The Gauge on the lowside is giving you the pressure of your evap in other word SSP ( Saturated Suction Pressure) use the PT Chart to get your SST
Line - SST = Superheat
Or Line - Gauge temp.
For Subcooling
Most Residential condenser have a condenser split of 30 degrees and you have 80F OAT( Outdoor Air Temperature. Another way to check what your condenser should be on a day like 80F
Condensing split: 30+80(OAT)= 110F
That a rough estimate on what your condensensing temperature should be SCT ( Saturated Condensing Temperature). If its higher than 110F on 80F day. Could mean dirty coil possibly the unit is over charged ETC
Most A/C have a 10Fdegree subcooling
Gauge110F - line100= 10degree subcooling
Or even check your delta T. Return temp and Supply temp.
Return temp at 72F supply 52F thats normal. If you had 72F return and 62F supply something definitely wrong.
72-52= 20 Delta T. Thats good
The reason we check total superheat at the compressor is because there is no port at the evap coil and techs don't take the time to remove the cover plate, find where the sat state will be at and tape a sensor there temporarily. There is a port at the outdoor unit and it is essential that we check if there is total superheat present there for the compressor's safety. I wrote full articles on our website about these topics at www.acservicetech.com/articles thanks Tmac 01!
@@acservicetechchannel i get that 100%. Also next time in your video you should also do Pressure/Enthalpy chart and psychrometric charts after you calculate your subcooling and superheat. Include that next time. Good video
Any recommendations for inexpensive thermostat I can use to measure line temps? Can I use a probed thermostat like Klein ET05 by touching the probe to the lines or do I need clamps? It appears you are using Fieldpiece ST4 in the video with the included leads (no clamps).
I been watching alot of ur vid! Great work👏..hopefully u can make a commercial fridge & freezer book. I don't see good vids out there and you my friend make AWESOME vids. Thanks so much! Much ❤ from san diego! LIKED & SUSCRIBED FOESHHEEZZZY!
Great video! Let’s say the TXV is malfunctioning in the close position, would the Evaporator start freezing? What if I think that is low on Refrigerant, and I add Refrigerant; how would that reflect on my pressures or superheat and subcooling?
Hey Abner, yes if the txv was mainly closed but letting a small amount of refrigerant through, the sat temp would be low and the coil would freeze. A liquid line restriction would be high superheat and normal to high subcooling. If you added refrigerant, it will just increase subcooling and the superheat will remain about the same, thanks!
Nice job and video
You're measuring actual superheat. How would you determine target superheat when the wet-bulb and dry-bulb temperatures are so close? WB 70°, DB 71°.
Good to know. Now, since this system uses R-410A, you state to check both the superheat and the sub-cooling temperatures to see if they are correct. If this method ONLY good for R-410A refrigerant or should you use this method to check earlier systems using R-22 refrigerant? Keep your videos coming. Thanks
does the refrigeration changes with a different refrigerants?
Same concept, R22 has different pressures so obviously different numbers.
Thanks Steven, total superheat and subcooling need to be checked on all ac units regardless if they have r22 r410a or another refrigerant, thanks Dennis, and John!
Use it for all refrigerant basicly
so the the suction line the bigger 7/8 line and the smaller pipe the 3/8 liquid line? does that mean 7/8 is the superheat and the 3/8 is subcool?
That is correct.
How do you get the temperature of the line?
What is the option when there is no subcool rating on the name plate. Most units don't have that info. Thanks I've purchased your book!
Is this also applicable for mini split system with service port only at the suction line?
89 - 74.5 is 14.5 so you're actually 1 degree closer to spec than you thought.
Wow, yeah, sorry about that!
hi, when standing pressures don't equalized (unit off) . does this mean there's a restriction? (i.e. R410A low side is around 150psig and high side is around 300psig). thank you.
It could just be a hard shut off TXV. If there was a restriction that wouldn't let the system equalize then the system would not work at all and it would break the compressor. Once the compressor turns on and pressurizes the line, the txv opens and allows refrigerant through, thanks!
TX valve could be the problem or even check Filter drier
So 10-14 is where we want SH?
In general
You're saying to check superheat only when it's 70 degrees indoor and outdoor, what do you do when it's under 70 outdoor?
Hey , what is reason ,have a refrigerant leak do oil analysis first , so how is done ?
Great videos, thanks a lot.... It's possible to know if Evap has TXV or Piston only by the checking the gauge or by superheat and subcooling values?
ho im hvac student im wondering how know what is the right superheat and subcolling on a system? i bought your book by the way
Awesome, so superheat and subcooling targets are in chapt 7, thanks!
Awesome video. What if TXV was added or for some reason target subcooling is not marked?
He sounds a bit like a Rick and Morty commercial, especially when bringing out the ac service tech book
Is your DT4 reliable? Mine seems confused...
If you charge by subcooling but check superheat how do you know what the correct superheat should be on each unit
Just placed an order for the book. Any info for walk in cooler/freezer?
Its mainly about air conditioning but the preparation steps are the same. I also talk about the txv, three position service valves, and the receiver, thanks!
@@acservicetechchannel Thank you
we don't know the target superheat for the load in the house. we we not told the indoor wet bulb. we were told about a 70 degree dry bulb.
dry bulb is read at subcool.(right after the condenser).Wet bulb is read (right after the evaporator.)Sling schychometer.
@@kengardner5097 for a non txv system, a derived taget superheat is required. review your studies of basic psycometric charts. start with a NATE refresher.
Great video...I have learned a considerable amount from your content. I am not a technician but a home owner with refrigerated air. However, I am seriously considering going into the field. Here is my dilemma. I would not be able to attend my local community college until spring of 2020 due to other commitments. Is there any other way to get the HVAC education in order to be certified in Texas. I have looked into online programs but have not been able to find any substantive reviews in regards to this type of HVAC training. I have considered Ron Walker's HVAC training solutions (he is on youtube as well). What would you or your viewers suggest? Should I wait and go through community college or is the online route a legitimate option? I would appreciate your input. I will continue to follow you and definitely will be purchasing you book.
J K I registered an online HVACR program at the beginning of this year ( 01/01/2019) and graduated in April. Got EPA universal certification in May. Bought a lot of tools and played on my own AC. I have learned a lot from UA-cam videos. With Joblink smart probe kit I offer free diagnosis to my friends AC and walk in coolers( restaurant owners). Learned a lot so far!
JK, There are lots of great learning sources available cheap! Check out hvacrschool.com. Craig’s book is great. Lots of great used “cheap” books at Amazon.com. I used “Moderm Refrigeration and Air Conditioning “. NATE study manuals are cheap. EPA section 608 study guides were available free. Or you may purchase reasonably priced.
Study at you own pace and for cheap. I’ve been doing the studying and testing as a hobby. Good luck 👍🏽. Enjoy
@@UltraHydrophobiccoat, if you don't mind me asking, what online program did you pursue and what was the cost? I have also learned a great deal from youtube as well and have used that information to fix my AC a couple of times. However, I have not started to build my tool kit as of yet.
@@chuckdearruda6271 thanks for the information. I took a look at the hvacrshool.com. That seems to be geared towards individuals that are already techs. However, it definitely seems to have information I would need once I became a tech. Also, I appreciate the other information on study materials. What are your feelings about using an online program?
JK, There is sooooo much great info Free online.
ua-cam.com/video/15ZrpM41enE/v-deo.html
Start here then Google or search within UA-cam (HVAC). (Stephen reardon) (Grayfurnaceman) Dr Z),
Study what you want, when you want,,,, Free!
Enjoy the journey
You can’t go wrong with teachers like Bryan Orr and Jim Bergmann. Checkout (free) educational stuff at the TruTechTools website too.
When in doubt, Google
Living in Texas but you say Cape May County did you originally start in Philly cause you seem familiar even though dont get to see you in the videos and yes your videos are very informative
Born and raised in Atlantic & Cape May County NJ. I haven't worked in Philly, thanks!
you made a mistake at 5:19 mark you said because our total super heat was 3.5 higher than our target we should recover when you should of said ADD refrigerant. also ive read its ok if its a 5 degree difference because you never want to add charge for the risk of overcharging and damaging the compressor.
I am in my last semester of HVAC/R and I am working on a condenser unit (w/o heat pump) that has 2 compressors, the contactors are labeled HI and LO. How do I check the charge on it? I am about 90% sure it is low on charge because I have a high super heat (25+), low suction pressure (105) and low sub cool (3.8 - 4.5).
Craig,
Where did you get the range of 10-14 degrees of superheat for the Txv as the correct superheat for the system? I know the target subcooling is on the data plate but where is that superheat range from? Is that from the outdoor temp/in door wb temp chart?
That is from manufacturers and TXV install manuals and from experience seeing it on properly working systems, thanks!
@@acservicetechchannel Ok got you. I am assuming TXV manuals come from when purchasing a new TXV?
Your pretty awesome at teaching this stuff. What’s wrong with your uei do you not trust the temp gauge anymore? I have the 429b and mine are off.
I just love the ST4 so much that I just use that now. Its a dedicated dual temp meter thats pretty inexpensive and has calibration screws, thanks!
What’s the name of the tool you are using for su cooling and superheat and where can I buy your book
You can find the tools we used and our book on acservicetech.com!!
Hi! I noticed that the superheat and subcooling are almost equal. Is this an indication of a properly charged system? I'm planning to service my car AC and there is no info about how much (in weight) should the charge be. Is it safe to assume that the subcooling should be around 11 - 14 degrees? The system uses TXV btw. thanks!
Craig while conecting my gauges in some hvac systems ,refrigerant flashback or scape and there is nothing wrong with the o rings (gaskets)
Alex Luna sounds like you need low loss fittings
Hello
I have an air conditioner , i want to know what does mean by design pressure
HI 446 PSIG
LO 236 PSIG
which wrote in the out door unit ?
Most of A/C units write in the nameplates low pressure and high pressure in Kpa but i don't know what they mean by that .
Where do you check that it is seventy degrees inside
When looking at the manual for my condenser (American Standard 2-stage unloading scroll), it says to increase the subcooling target for lift and lineset length. My evaporator coil is in the attic above the 3rd floor, so it has a very long lineset with 3 floors worth of lift, which is at the max limit for that model. So that would be the 9 degree default on the plate/manual plus 3 degrees for lift and length, for a total of 12 degrees subcooling. When techs come and check the charge, they only look at the plate which says 9 degrees +/- 3 degrees. So if it was at 9 degrees, should they bring it back up to 12 degrees? And would the new MAX subcooling still be 12? Or would the new MAX be 15?
Need head pressure control for winter time high side lift to evap.
another great video I was wondering do you temp rise, cfm furnace data in your ac service tech manual?
I do mention them in the book and give an example with a pic for the temp rise formula, thanks!
Do much work on systems with hot gas bypass?
Not that much nowadays but sometimes depending on a commercial job or smaller ice makers, thanks!
How do you check subcooling (unit has a TXV) if nameplate has no saturation temp value??
I usually use 10 degrees if no other info is available.
Yes 11 degrees is a good number if the rating p[late is worn off.
look under cover to contactor.
Hi, just a question I bought 2nd hand mini split and now I checked compressor and it shows 1.3ohm across any of 3 pins is that correct ?
Yes.
Yes thats correct and thanks Car U!
Can you explain it to me please why other compressors have the sum of 2 pins equivalent to 3 pin and my has all the same just want to understand it fully please
I gotta question, maybe someone can answer. Sub-cooling is saturated temp minus actual temp and super heat is actual temp minus saturated temp. If you're measuring sub-cooling, then why not do both the same way as superheat such that sub-cooling gets you a negative number, like -13°F instead of +13°F sub-cooling? Then using proper math you can see the temperatures increasing and decreasing as it actually is.
You just blew my mind! Kind of makes sense since the liquid temp exiting the condenser should be about 10 degrees cooler than the saturated refrigerant in the condenser. You are going to turn the HVAC industry upside down with that kind of thinking. What I don't understand is how we take pressure measurement at the service port location and extrapolate that same pressures to the middle of condenser and evaporator. Are the P/T charts already adjusted for this difference in Pressure vs Temp?
What happens when the data plate/ sticker is unreadable? For target SH or SC? Thanks
google
What would happen if the saturated temp is below 32°?
Tommy, at what temperature does water freeze?
If your evaporator coil is at or below 32 degrees and there is any humidity in the space being cooled it will begin to form frost on the coil and begin to restrict airflow thru the coil.
If the sat temp is below 32 degrees, the coil will freeze the humidity crossing the coil. This could be due to a low refrigerant charge, liquid line restriction or low airflow, thanks!
Thank you guys!
@@acservicetechchannel os the only way liquid restriction happens is because air bubbles ?
use temp pressure chart for your type of refrigerant.
Hi, great instructional videos :) Do you know what the discharge line temperature is on most R32 heat pumps in heating mode is for homeowners?
I have a accumulator and compressor that's freezing up as soon as you turn i cound this be restriction it's a TXV or at the emulator?
Sounds like flood back. overcharge.
Why can't I just make sure that the temperature on the vapor side is between 40 and 50 degrees F? That's what I've seen some many other techs do
The txv by design is continuously adjusting the superheat within a certain range......so that does not allow you to accurately measure the actual charge of the system(via superheat). The system could be over/undercharged and the txv would be trying to compensate for the current charge state. Why NOT check the subcooling?!?!?
@@ruftime So then why do I see so many installers doing this in my company? Also, the AC systems seem to work okay and they are not hooking up to the high pressure part.
Jackson, I’m guessing the culture of your company allows/encourages this practice. I’m sure most of the time it gets the job done, just like those automotive A/C recharge cans with one gauge!?!? But ultimately everyone is losing out, especially the technician if he wants to get better. Fully hooking up to systems will give you an ever growing perspective on what to expect and how to diagnose BEFORE wasting your time recharging. It’s not the wrong way, but it’s not right either:-)
Hey Jackson, I would not bust the higher techs chops too much since they are higher in the company than you but when you are out on your own, you can do the procedures properly and check both superheat and subcooling. This will give you a real glimpse into what is happening in the system and they are the proper charging method, thanks Canyon Racer!
Thanks guys, I appreciate the advice
What if the super heat is in the 20s.. I see this all the time
overcharge.
Love your content but you talk so fast I have a hard time keeping up and it hurts my head lol. Any other channels you can maybe recommend for someone slow like me?
Is it possible that the txv is in the outdoor unit? If so, how do we measure the super heat and sub cool?
Only on heat pumps.
Sir hindi
That book is way to expensive
That is the main product we sell in order to create all the free training videos. Its ok and just watch the free videos and learn as much as you can, thanks!
Is this also applicable for mini split system with service port only at the suction line?