Tool List- www.amazon.com/shop/acservicetech Support- www.patreon.com/acservicetech For those that are looking for the tools used in the videos: (Linked Below) Here is the Link for the Yellow Jacket Refrigerant Manifold Gauge Set used in the videos- amzn.to/2aenwTq Here is a link to Refrigerant hoses with valves used in the videos- amzn.to/2aBumVI Here is a link to the UEI DL389 Multimeter used in the videos- amzn.to/2xAdaJf Here is a link to the Imperial 535-C Kwik Charge Vaporizer for Charging Refrigerant- amzn.to/2wFHtBW Here is the link to the Fieldpiece ST4 Dual Temp Meter- amzn.to/2wc1ME3 Here is a link to the Digital Refrigerant Scale used in the videos- amzn.to/2b9oXYl Here is a link for RectorSeal Bubble Gas Leak Detector amzn.to/2ckWACn Other tool links can be found in the video description section. ACSERVICETECH is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon. Check out other videos on the HVACR topics of interest at- th-cam.com/channels/OZR-1IqsAer9wzlvFgb4mA.htmlplaylists?view_as=public If you want to support the ACSERVICETECH Channel and receive more HVAC content, check out www.Patreon.com/acservicetech
I’m not an AC tech, but I have acquired a fair understanding of auto AC/ construction equipment systems, but after watching this video it explains some of my long unanswered questions!!!!!! Thank you for sharing!!!!!!!
Another 1st-Class instructional video. How I wish you and TH-cam had been around when I was starting out. Learning would not only have been easier, it would have been better. You probably don't hear it enough, but many thanks on behalf of all the new techs who have found this terrific resource.
I ditto that too. It would have been great to have some examples back then to watch when I was starting out. I just kept running into systems or components I had never seen and made many late night calls to other service techs to ask questions. These individuals cared and always took my call and it was appreciated. I learned a lot!
This is the best explanation of which direction to go when you see the pressures are not where they should be. I've watched several TH-cam channels on HVAC to decide on which channel I could learn the most. I've subscribed to your channel a couple of weeks ago and have been watching quite a few of your videos. I've compared you to other HVAC tech channels, and yours is by far the best in your detailed explanation of understanding refrigeration. Thank you sir for your commitment to share your knowledge and experience with others. And as mentioned, I had to put the headphones on as the audio was very low even when turned up at 100%. Have a great evening for the weekend that's left :)
Thanks stuzman, yeah I was just commenting back to TurboFlush and I am going to be looking into what the next steps will be in reference to audio, thanks.
Thank you for all your training videos. Been in the trade 30 + years, most of that time as a installer. Started service full time a few years ago. Your videos have been extremely helpful. Have been passing them on to all our younger techs. Please don't stop sharing.
great video, keep them coming. thank you for taking the time to share your knowledge. I for one greatly appreciate you taking the time to make these informative videos.
If you want to support the ACSERVICETECH Channel and receive more HVAC Content, Correspond, or Collaborate on your endeavors- check out www.Patreon.com/acservicetech All of the ACSERVICETECH Playlists- th-cam.com/channels/OZR-1IqsAer9wzlvFgb4mA.htmlplaylists?view_as=public Submit your email to the ACSERVICETECH email updates list at info@acservicetech.com
Greg if I have a 20° subcool temp difference. How can i remove refrigerant without dropping the superheat suction temp ?? Liqid line reads 110 ° on gages and 90° on the liquid line temp with clamp so that's a 20° difference? I have tried to add refrigerant and recover some to see if I can get in the ballpark of a 12° subcool.but that in return lowers my superheat or suction down to low or up to high ?? Is this due to a line restriction on a new system??? . Carrier 2ton ac txv indoor??
That would actually reduce the friction on the blower unless there is a closed room where it is located. Also the house would pressurize if the unit was located outside the conditioned area. There would also not be a filter to catch the dust. That is not a good thing to leave off either way, thanks!
No, Not removing the blower door completely and leaving it off for good, just having it off for a few minutes while it runs to see if pressures change, then place the blower door back on of course. I would never leave a blower door off completely.
I know you wouldn't from prior communications, I thought you were talking about something you ran into or a door that is rotted off on a service call. I have seen that before quite a bit from having the furnace in humid places or in flood areas in a basement. I understand what you meant now, a test, thanks!
So how would you know for sure if it was a restriction or low charge? I see how you can eliminate the airflow issue but without having to add refrigerant how can you tell if it’s low or restricted. Also if it is a piston how would you determine if the subcooling is to low or to high? Do you shoot for a 10 degree and determine from there.
It is true, that it is harder to distinguish between the two, liquid line restriction and low charge on a fixed orifice. Often times you see that whoever put the system or serviced last added extra refrigerant trying to get the vapor side pressure up higher resulting in a higher subcooling like 15 or more. Also since the sat state is smaller in the evap there will be a higher subcooling in the high side. Even when checking superheat, maybe take note how much subcooling there is. Sometimes it is quite high but is normal and ok since you are setting a unit with superheat. If the system was low on refrigerant then you would see around 6 degrees or less of subcooling. Yes it is harder to distinguish between a liquid line restriction on a piston than txv, thanks David! Your fallback will be adding refrigerant in to see if the vapor pressure rises because fixed orifice systems vapor side pressures will rise when adding refrigerant where as txv systems won't, thanks
I had a job last night where the outdoor unit( a HP) was tripping out on high head pressure. I put my gauges on and my readings were low side 78.1 psig and 19.4 degrees saturated. High side was 402.2 Psig and 117 degrees saturated. Super heat was 22.4 and subcool was 43.6. It was pretty cold last night so I expect my low side pressure to be low. I said it was a liquid line restriction. Main reason why is becuase I had 22 degrees superheat. Second another tech was out and added three pounds of refrigerant thinking the system was low on charge. I believe All he did was raise the high side and low side didnt budge. Since it was late and i was unable to do a refrigerant repair I had him turn off heat pump and run auxiliary heat. He said the system has been doing this for a couple of weeks. With the system short cycling like that I am wondering if there is any damage to compressor. Diagnosing a refrigerant issue is really tricky sometimes. I would say it's over charged but the superheat seemed normal/high. Do you think my diagnosis was correct? The high side was getting much higher than what I stated I only recorded those readings to have a reference. Thanks
Before diagnosing the problem in heat pump mode, it is important to try to get the charge close especially when you know it is overcharged. What outdoor ambient temp was it? Was it possible to check the charge in ac mode by restricting the outdoor fan airflow in order to drive the saturated temp of the outdoor coil up to around 95 degree saturated temp? It would have to be above 32 degrees outside and preferably above 37 degrees. We would do this with a piece of plywood if the top was flat or with a charging jacket for rounded shrouds. Make sure to not cover over the side fins but just the airflow output. What was the homeowners concern before he called out the first tech? Also any time a heat pump is running in heat pump mode below around 40 degrees outdoor ambient, the outdoor sat state will be freezing while running. it is not rare to have a low sat state such as 20 degrees at the outdoor coil. I am curious what the temp was though. It just sounds overcharged from what I can tell at this point. In reference to a liquid line restriction, you could check the temp decrease across the filter drier of higher than 3 degrees could be a restriction but usually it is higher than that. I was looking to do a video on checking the charge at a low outdoor ambient soon but it would be best to get the charge right if possible and then diagnose. Our problem with diagnosis in heat pump mode is the accumulator and not being able to tell how much refrigerant is in there, thanks David!
AC Service Tech LLC concerns had to do with the zone system he has. Damper motor had gone bad. I guess while tech was there he told home owner unit was under charged. Outdoor ambient was like 30 degrees. The unit would kick on for maybe 5 minutes before it kicked off on high pressure. I thought over charge but my superheat was 22 degrees. If my super heat was really low I would say overcharge for sure. Plus the compressor made the rattling sound right before it would cut out. I have heard what a compressor sounds like when over charged and it sounds like it’s gurgling and very loud. Maybe in Heat Pump mode it’s different
Hey David, something doesn't seem right and I do apologize, my mind is shot at this point tonight. You said the sat temp was 19.4 and if 22 degrees were added then it would be 41.4 which would make it having to be at least 41.4 degrees outdoor ambient in order for the heat to be absorbed. I am curious where the temp sensor was mounted for taking superheat exactly? You would need to have it on the vapor tube where the true suction port is coming from and it would need to be insulated. They don't make it easy to check superheat on them, ha ha, thanks
AC Service Tech LLC. My suction line temp was 41.8 my psig was 78.1 and the saturation temp was 19.4. I took my superheat on true suction near reversing valve. Maybe I said it wrong before. It said 30 degrees on the phone. In the measure quick app I used with my probes. Also my pressures did not equalize after unit cut off.
question a hack installed a used condenser 2.5 ton r22 to A system that had a 5 ton air handler. system ran for about 24 hours and blew out the compressor terminal. being severely mismatched do you think mismatch had to do with the (cause) compressor terminal blowing out? liquid in the compressor??
Was this a piston system or txv? Either way, this system would not work well at all. There will be too much superheat and too much hunting if there was a txv. The tech may have severely overcharged it in an effort to try to make it work right . Thanks
acservicetech thank you for the reply. this Hack That installed this did not know that the air handler was severely oversized until after the compressor terminal blowout. guessing he never looked at the air handler ? he replace the existing 2.5 ton condenser heat pump with a 2.5 straight cool. the straight cool was the one that blew the terminal out / copy someone else's screw-ups. therefore I am assuming he don't have a clue what type metering device the system has. and probably still don't know what type metering device? might be the worst hack job I have heard of? I am thinking something this hack did contributed to the compressor terminal blowing out?
Hey Steve, sorry I didn't catch this question earlier- For a gas furnace you can use the temp rise formula but it won't be exactly the same since it will be a wet coil during ac mode CFM = (Input BTU x combustion efficiency) / (1.08 x DT) For elect resistance CFM = (Volts x Amps x 3.41) / (1.08 x DT) or use an Anemometer and single large return grill opening with the grill off or FRAG open, thanks Steve!
A slightly dirty condensor would be the same thing as if it was 10 or 20 degrees hotter outside. It has a harder time rejecting heat. Target Subcooling should be close to the same as what is stated on the rating plate unless you are talking partially clogged. if anything, it would cause the actual subcooling to be slightly higher when the fins are slightly dirty. You should however, clean the coil before checking the charge, thanks D M!
I had one of these on a heat pump today. Compressor was running in a vacuum and head was 200 psi. Found a leak with soap bubbles at a connection for the 3 way. Fixed the leak and added exact mfg charge. Same thing happened so I decided to run the system in heat. When I ran it in heat the liquid line service valve would freeze and all the cap tubes after it as well. Pressures after the repair were better but still not good. Had 50 psi on low side, head was up at 225. The metering devices for both inside and out were pistons. I'm thinking the piston was clogged. Let me know what you think of this. Superheat was very high and subcooling was negative the whole time
It was a Bryant heat pump I was working on. It had a piston metering device at the lliquid line service valve. When I ran the system in heat mode I could see the service valve starting to freeze. Suction at true suction port was 50 psi, head pressure would start high and eventually drop to 0, liquid line temp would stay at 75 deg and then service valve would freeze. Ran it in ac and suction tanked, superheat was high, subcooling was in the negative. Went inside and took a peek at the indoor metering device and that was indeed a piston, which wasn't freezing and very warm to the touch as if no refrigerant was making it's way to that point. Honestly I kinda winged it and took a hand feel at the TD across the filter drier but it didn't seem abnormal. Same feel on both sides. But with a frozen service valve, I'd believe the restriction lies in that spot. I've seen restricted TXVs turn into a ball of ice. As I said. A new 3 way valve in this unit that was heavily brazed with visible carbon buildup kinda tells the reason for things.
Had a very similar situation, turned out coil was block, dirty and a,so a restriction. The clear plastic from fi,tee was sucked up and resting over coil. Customer must have opened filter close to return and never said anything about plastic being sucked in. Coil was also pretty dirty. However IR scan showed restriction in strainer at TXV also. What a mess....took care of all that everything good....
hi craig , can u check this for me . is this return air flow issue ? i think suction line is not cold enough. good man 3.5 ton r410a with txv suction pressure 122 psig liquid line pressure 288 psig suction line 62 f liquid line 84 f superheat 20f subcool 10f out door 78f return wetbulb -60 return dry bulb 74 supply -58
That could be high airflow possibly, the sat temp on the low side is maybe a little high but not much at around 42 degree sat temp. The long and short is that the txv is not holding a low enough superheat. That could mean a partial liquid line restriction or a mismatch of one of the components. If the TXV is rated for 18,000 to 36,000 then that would be too small or if the coil was too sized too big. It would be nice to have 10 to 14 degrees of superheat which would absorb more heat at the indoor coil.
@@acservicetechchannel thank u for reply.. im a new tech .so i dont know much on trouble shoot . this is my own house , i install this like 2 month ago whole brand new system with ducting . coil is build with txv . air flow from supply is kinda strong . what should i check to fix this issue . i check filter dyer has no problem .
If the superheat is very high at around 42(suction line temp 86, saturated temp 44) and subcooling is almost zero, does that mean the system is undercharged?
acservicetech just doesn't have the quality sound. I have to be in a quiet area. it's been like that for many videos. might help those that have a hard time with your "accent". lol
Tool List- www.amazon.com/shop/acservicetech
Support- www.patreon.com/acservicetech
For those that are looking for the tools used in the videos: (Linked Below)
Here is the Link for the Yellow Jacket Refrigerant Manifold Gauge Set used in the videos- amzn.to/2aenwTq
Here is a link to Refrigerant hoses with valves used in the videos- amzn.to/2aBumVI
Here is a link to the UEI DL389 Multimeter used in the videos- amzn.to/2xAdaJf
Here is a link to the Imperial 535-C Kwik Charge Vaporizer for Charging Refrigerant- amzn.to/2wFHtBW
Here is the link to the Fieldpiece ST4 Dual Temp Meter- amzn.to/2wc1ME3
Here is a link to the Digital Refrigerant Scale used in the videos- amzn.to/2b9oXYl
Here is a link for RectorSeal Bubble Gas Leak Detector amzn.to/2ckWACn
Other tool links can be found in the video description section.
ACSERVICETECH is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.
Check out other videos on the HVACR topics of interest at- th-cam.com/channels/OZR-1IqsAer9wzlvFgb4mA.htmlplaylists?view_as=public
If you want to support the ACSERVICETECH Channel and receive more HVAC content, check out www.Patreon.com/acservicetech
I’m not an AC tech, but I have acquired a fair understanding of auto AC/ construction equipment systems, but after watching this video it explains some of my long unanswered questions!!!!!! Thank you for sharing!!!!!!!
Wow, thanks!
Another 1st-Class instructional video. How I wish you and TH-cam had been around when I was starting out. Learning would not only have been easier, it would have been better. You probably don't hear it enough, but many thanks on behalf of all the new techs who have found this terrific resource.
I ditto that too. It would have been great to have some examples back then to watch when I was starting out. I just kept running into systems or components I had never seen and made many late night calls to other service techs to ask questions. These individuals cared and always took my call and it was appreciated. I learned a lot!
This is the best explanation of which direction to go when you see the pressures are not where they should be. I've watched several TH-cam channels on HVAC to decide on which channel I could learn the most. I've subscribed to your channel a couple of weeks ago and have been watching quite a few of your videos. I've compared you to other HVAC tech channels, and yours is by far the best in your detailed explanation of understanding refrigeration. Thank you sir for your commitment to share your knowledge and experience with others. And as mentioned, I had to put the headphones on as the audio was very low even when turned up at 100%. Have a great evening for the weekend that's left :)
Thanks stuzman, yeah I was just commenting back to TurboFlush and I am going to be looking into what the next steps will be in reference to audio, thanks.
You are a real Master of the A/C science , I spent 20 years on far sea going reefers and I am able to estimate your knowledge.
Thank you very much Joeval!
Thank you for all your training videos. Been in the trade 30 + years, most of that time as a installer. Started service full time a few years ago. Your videos have been extremely helpful. Have been passing them on to all our younger techs. Please don't stop sharing.
That's great to hear William, thanks!
Great video I had a unit yesterday with very high subcooling and superheat this clears it up for sure!
Thanks Brandon!
Clarifies how to diagnose low air flow. Thanks for posting.
Thanks Ken! Glad it helped!
great video, keep them coming. thank you for taking the time to share your knowledge. I for one greatly appreciate you taking the time to make these informative videos.
Thank you very much eddie!
Thank you for all your training videos. Really helpful and well explained. Thank you for your time and shared knowledge.
Thanks Octavio!
Very real world example and awesome explanation, great video!! Thank you.
Thanks Michael!
acservicetech- As usual you deliver excellent, well done instructional video. I always enjoy viewing. Keep up the good work. Cheers!!
Thank you very much Paul!
Excellent teaching!
Thanks attisso!
If you want to support the ACSERVICETECH Channel and receive more HVAC Content, Correspond, or Collaborate on your endeavors- check out www.Patreon.com/acservicetech
All of the ACSERVICETECH Playlists- th-cam.com/channels/OZR-1IqsAer9wzlvFgb4mA.htmlplaylists?view_as=public
Submit your email to the ACSERVICETECH email updates list at info@acservicetech.com
thanks for the video, ran into this problem the other day
Thanks Bryan!
Great video . Excellent explanation!
Thanks Air Mechanical!
Greg if I have a 20° subcool temp difference. How can i remove refrigerant without dropping the superheat suction temp ?? Liqid line reads 110 ° on gages and 90° on the liquid line temp with clamp
so that's a 20° difference? I have tried to add refrigerant and recover some to see if I can get in the ballpark of a 12° subcool.but that in return lowers my superheat or suction down to low or up to high ?? Is this due to a line restriction on a new system??? . Carrier 2ton ac txv indoor??
Great Video! I've also heard of a low airflow issue being found by removing the indoor blower door and letting the system run.
That would actually reduce the friction on the blower unless there is a closed room where it is located. Also the house would pressurize if the unit was located outside the conditioned area. There would also not be a filter to catch the dust. That is not a good thing to leave off either way, thanks!
No, Not removing the blower door completely and leaving it off for good, just having it off for a few minutes while it runs to see if pressures change, then place the blower door back on of course. I would never leave a blower door off completely.
I know you wouldn't from prior communications, I thought you were talking about something you ran into or a door that is rotted off on a service call. I have seen that before quite a bit from having the furnace in humid places or in flood areas in a basement. I understand what you meant now, a test, thanks!
So how would you know for sure if it was a restriction or low charge? I see how you can eliminate the airflow issue but without having to add refrigerant how can you tell if it’s low or restricted. Also if it is a piston how would you determine if the subcooling is to low or to high? Do you shoot for a 10 degree and determine from there.
It is true, that it is harder to distinguish between the two, liquid line restriction and low charge on a fixed orifice. Often times you see that whoever put the system or serviced last added extra refrigerant trying to get the vapor side pressure up higher resulting in a higher subcooling like 15 or more. Also since the sat state is smaller in the evap there will be a higher subcooling in the high side. Even when checking superheat, maybe take note how much subcooling there is. Sometimes it is quite high but is normal and ok since you are setting a unit with superheat. If the system was low on refrigerant then you would see around 6 degrees or less of subcooling. Yes it is harder to distinguish between a liquid line restriction on a piston than txv, thanks David! Your fallback will be adding refrigerant in to see if the vapor pressure rises because fixed orifice systems vapor side pressures will rise when adding refrigerant where as txv systems won't, thanks
I had a job last night where the outdoor unit( a HP) was tripping out on high head pressure. I put my gauges on and my readings were low side 78.1 psig and 19.4 degrees saturated. High side was 402.2 Psig and 117 degrees saturated. Super heat was 22.4 and subcool was 43.6. It was pretty cold last night so I expect my low side pressure to be low. I said it was a liquid line restriction. Main reason why is becuase I had 22 degrees superheat. Second another tech was out and added three pounds of refrigerant thinking the system was low on charge. I believe All he did was raise the high side and low side didnt budge. Since it was late and i was unable to do a refrigerant repair I had him turn off heat pump and run auxiliary heat. He said the system has been doing this for a couple of weeks. With the system short cycling like that I am wondering if there is any damage to compressor.
Diagnosing a refrigerant issue is really tricky sometimes. I would say it's over charged but the superheat seemed normal/high. Do you think my diagnosis was correct? The high side was getting much higher than what I stated I only recorded those readings to have a reference. Thanks
Before diagnosing the problem in heat pump mode, it is important to try to get the charge close especially when you know it is overcharged. What outdoor ambient temp was it? Was it possible to check the charge in ac mode by restricting the outdoor fan airflow in order to drive the saturated temp of the outdoor coil up to around 95 degree saturated temp? It would have to be above 32 degrees outside and preferably above 37 degrees. We would do this with a piece of plywood if the top was flat or with a charging jacket for rounded shrouds. Make sure to not cover over the side fins but just the airflow output. What was the homeowners concern before he called out the first tech? Also any time a heat pump is running in heat pump mode below around 40 degrees outdoor ambient, the outdoor sat state will be freezing while running. it is not rare to have a low sat state such as 20 degrees at the outdoor coil. I am curious what the temp was though. It just sounds overcharged from what I can tell at this point. In reference to a liquid line restriction, you could check the temp decrease across the filter drier of higher than 3 degrees could be a restriction but usually it is higher than that. I was looking to do a video on checking the charge at a low outdoor ambient soon but it would be best to get the charge right if possible and then diagnose. Our problem with diagnosis in heat pump mode is the accumulator and not being able to tell how much refrigerant is in there, thanks David!
AC Service Tech LLC concerns had to do with the zone system he has. Damper motor had gone bad. I guess while tech was there he told home owner unit was under charged. Outdoor ambient was like 30 degrees. The unit would kick on for maybe 5 minutes before it kicked off on high pressure. I thought over charge but my superheat was 22 degrees. If my super heat was really low I would say overcharge for sure. Plus the compressor made the rattling sound right before it would cut out. I have heard what a compressor sounds like when over charged and it sounds like it’s gurgling and very loud. Maybe in Heat Pump mode it’s different
Hey David, something doesn't seem right and I do apologize, my mind is shot at this point tonight. You said the sat temp was 19.4 and if 22 degrees were added then it would be 41.4 which would make it having to be at least 41.4 degrees outdoor ambient in order for the heat to be absorbed. I am curious where the temp sensor was mounted for taking superheat exactly? You would need to have it on the vapor tube where the true suction port is coming from and it would need to be insulated. They don't make it easy to check superheat on them, ha ha, thanks
AC Service Tech LLC. My suction line temp was 41.8 my psig was 78.1 and the saturation temp was 19.4. I took my superheat on true suction near reversing valve. Maybe I said it wrong before. It said 30 degrees on the phone. In the measure quick app I used with my probes.
Also my pressures did not equalize after unit cut off.
question a hack installed a used condenser 2.5 ton r22 to A system that had a 5 ton air handler. system ran for about 24 hours and blew out the compressor terminal. being severely mismatched do you think mismatch had to do with the (cause) compressor terminal blowing out? liquid in the compressor??
Was this a piston system or txv? Either way, this system would not work well at all. There will be too much superheat and too much hunting if there was a txv. The tech may have severely overcharged it in an effort to try to make it work right . Thanks
acservicetech thank you for the reply. this Hack That installed this did not know that the air handler was severely oversized until after the compressor terminal blowout. guessing he never looked at the air handler ? he replace the existing 2.5 ton condenser heat pump with a 2.5 straight cool. the straight cool was the one that blew the terminal out / copy someone else's screw-ups. therefore I am assuming he don't have a clue what type metering device the system has. and probably still don't know what type metering device? might be the worst hack job I have heard of? I am thinking something this hack did contributed to the compressor terminal blowing out?
Another great video! Thank you.
Thanks DC!
Great Video. Thank you!
Thanks Blue Collar!
How do you check and make sure the air flow is correct coming out of the registers? What meter or instrument do you use?
Hey Steve, sorry I didn't catch this question earlier- For a gas furnace you can use the temp rise formula but it won't be exactly the same since it will be a wet coil during ac mode CFM = (Input BTU x combustion efficiency) / (1.08 x DT) For elect resistance CFM = (Volts x Amps x 3.41) / (1.08 x DT) or use an Anemometer and single large return grill opening with the grill off or FRAG open, thanks Steve!
If the low side it’s 145 pis and high side goes up to 700 pis is this a good sign that we have bad txv
another good vid. we get this problem here at our facility.
Thanks TurboFlush!
For the air flow , instead of checking all the grills , could we just do the temp rise method using the heat strips ?
Absolutely, that's a great method, thanks!
How do you determine if the duct work is properly and return?
How important is it that the condenser be clean when checking the subcooling? Will a dirty condenser affect the subcooling that much?
A slightly dirty condensor would be the same thing as if it was 10 or 20 degrees hotter outside. It has a harder time rejecting heat. Target Subcooling should be close to the same as what is stated on the rating plate unless you are talking partially clogged. if anything, it would cause the actual subcooling to be slightly higher when the fins are slightly dirty. You should however, clean the coil before checking the charge, thanks D M!
Great video
Thanks MrJr669!
I had one of these on a heat pump today. Compressor was running in a vacuum and head was 200 psi. Found a leak with soap bubbles at a connection for the 3 way. Fixed the leak and added exact mfg charge. Same thing happened so I decided to run the system in heat. When I ran it in heat the liquid line service valve would freeze and all the cap tubes after it as well. Pressures after the repair were better but still not good. Had 50 psi on low side, head was up at 225. The metering devices for both inside and out were pistons. I'm thinking the piston was clogged. Let me know what you think of this. Superheat was very high and subcooling was negative the whole time
Are you saying no subcooling and high superheat when checking the charge in ac mode? If so, the unit sounds still low on refrigerant, thanks!
It was a Bryant heat pump I was working on. It had a piston metering device at the lliquid line service valve. When I ran the system in heat mode I could see the service valve starting to freeze. Suction at true suction port was 50 psi, head pressure would start high and eventually drop to 0, liquid line temp would stay at 75 deg and then service valve would freeze. Ran it in ac and suction tanked, superheat was high, subcooling was in the negative. Went inside and took a peek at the indoor metering device and that was indeed a piston, which wasn't freezing and very warm to the touch as if no refrigerant was making it's way to that point. Honestly I kinda winged it and took a hand feel at the TD across the filter drier but it didn't seem abnormal. Same feel on both sides. But with a frozen service valve, I'd believe the restriction lies in that spot. I've seen restricted TXVs turn into a ball of ice. As I said. A new 3 way valve in this unit that was heavily brazed with visible carbon buildup kinda tells the reason for things.
This is a great video, very informative. Also, I would like to point out the fact that I am the first to comment. That just now happened.
Brad Settle
your second lol.
Thank you very much Brad and yes very close!
Great video thank you.
Thanks a lot Ron!
Had a very similar situation, turned out coil was block, dirty and a,so a restriction. The clear plastic from fi,tee was sucked up and resting over coil. Customer must have opened filter close to return and never said anything about plastic being sucked in. Coil was also pretty dirty. However IR scan showed restriction in strainer at TXV also. What a mess....took care of all that everything good....
Good stuff!!!
Thanks Steven Gilber!
hi craig , can u check this for me . is this return air flow issue ?
i think suction line is not cold enough.
good man 3.5 ton r410a with txv
suction pressure 122 psig liquid line pressure 288 psig
suction line 62 f liquid line 84 f
superheat 20f subcool 10f
out door 78f
return wetbulb -60
return dry bulb 74
supply -58
That could be high airflow possibly, the sat temp on the low side is maybe a little high but not much at around 42 degree sat temp. The long and short is that the txv is not holding a low enough superheat. That could mean a partial liquid line restriction or a mismatch of one of the components. If the TXV is rated for 18,000 to 36,000 then that would be too small or if the coil was too sized too big. It would be nice to have 10 to 14 degrees of superheat which would absorb more heat at the indoor coil.
@@acservicetechchannel thank u for reply..
im a new tech .so i dont know much on trouble shoot . this is my own house , i install this like 2 month ago whole brand new system with ducting .
coil is build with txv . air flow from supply is kinda strong . what should i check to fix this issue . i check filter dyer has no problem .
Merci pour la video et la bonne explication très claires
Thanks Salvador Dali!
If the superheat is very high at around 42(suction line temp 86, saturated temp 44) and subcooling is almost zero, does that mean the system is undercharged?
Seems undercharged but I am surprised the sat temp is so high instead of being lower close to freezing. Is it very hot and humid in the building?
It's about 79 inside the house and the humidity is not very high.
Ok yeah it sounds low, thanks
A little tougher scenario but given time he would figure it out.
Some companies don’t want to give you the allotted time to actually diagnosed
ty u r great
Glad to Help David!
A little tougher scenario but given time he would figure it out.
And I forgot to add that the outside temp was 65 and inside was 72
That is close to the minimum 70 outside and 70 inside though
PLEASE USE A BETTER MIC!
Thanks for letting me know!
Please use a new microphone.
eyeeye1
wouldn't hurt.
Thanks for both of you letting me know. Yeah, this one seems to have a little echo
acservicetech
just doesn't have the quality sound. I have to be in a quiet area.
it's been like that for many videos.
might help those that have a hard time with your "accent". lol
Yeah Ha Ha, that Jersey Accent! You are right, I am going to do some research, thanks