So I’ve ran into some calls where the head pressure is staying stable between 350’s 360’s psi and the suction steady goes up , superheat stays high sub cooling goes up to five back down to zero I’m confused
So I was told I have a restricted TXV line and it cannot be replaced because it’s sautered of some sort? Is there a reason for this? They quoted me $6,500 for a fix….
I'm wondering how cool of a day it is there because your head pressure is really low for r-410a. Also the txv controls the superheat of the system so it's important to charge the system using subcool method, but seeing as it's a package unit you can weigh in the charge. Tv's can also fail by not opening all the way or getting stuck open. Carrier valves usually get stuck closed, however.
My gauges have shown me low suction pressure, with normal head pressure. for example 106 L / 310 H. Always consider ambient temperature inside the house. Temperature AFFECTS pressures. Temperature rises > Pressure Rises. So if its 82 degrees inside the house EXPECT low side to be in your 130s, but if you go outside to your gauges and your reading 106 L, with normal head pressure and sub cool, than you have a restriction of some sort. Check filter dries temperature difference, kinks on liquid line by condenser or attic people can step on them (landscape people, customer putting boxes in attic walkin in attic, etc) or stuck TXV. Hopes this helps. Remember, TEMPERATURE AFFECTS PRESSURES !
I respectfully disagree that a bad TXV causes high head pressure, unless it has pumped down to the point of having filled the condenser with liquid refrigerant to near the top. Your not absorbing any heat at the evaporator if you are running 0 psi, so there is no heat, except heat from the compressor motor,to be rejected by the condenser. If you have O psi on the low side, you have essentially pumped the system down. There should be enough room in the condenser for the backed up liquid refrigerant. If someone has overcharged the system, because of seeing low suction pressure, there may not be enough room left in the condenser, then the high side pressure would go up. Air and non condensibles would also cause the high side pressure to go up. If it is true that you had high head or high head pressure with O lbs low side because of the bad TXV, you would also have an overcharge, or air and non condensibles. Just my opinion. Did you measure the amount of refrigerant you got out when you recovered? If so, how did it compare with the name plate charge?
@@TaddyDigestcan you upload the video follow up to the detail section of this video? Thank you for your on the field footage. This is super helpful for junior technicians who fail to have a good understanding of the refrigeration cycle in real life. There’s a vast difference between the textbook description of the refrigerant cycle versus what one encounters on the field. Keep up the good work.
If the return temperature is seventy seven, and the supply air temperature is fifty-five, that's great .What is the return air temperature near the thermostat If you only have an eleven degree split Check your duck work for air leaks. Check the charge of the equipment and check the airflow.
Thank you for the video. I have a system R410A with TXV, low 160PSI, high 280 PSI, indoor delta T only 8F. Outdoor not blowing hot air. It is very hot and humid day. I noticed from the photo before installation, the bulb isn't insulated. Is this the cause?
Wow what a wonderful thing to say I really appreciate you saying this this makes me feel very good I appreciate you and I hope you have a wonderful day
I am trying to detect an empty TXV bulb in an outdoor unit and i am trying to see a difference between a good unit and a bad TXV unit, so is this the only method by which we can detect an empty TXV or is there any other method that can help?
That is the worst advice I’ve ever heard. your superheat will tell you if the txv is working correctly most of the times. But never go off of pressures. The only reason you’re taking pressures is to get the saturation temp. Subcooling Per manufacturer’s Instructions to charge with a txv. Txv superheat will between 8-12.
very informative video thanks for shear your experience, I got a 4 tons trane compessor cutting off for low pressure sometime after few secons it able to rise the low side and star back again but most of te time the pressure not going to equalize and because de low side pressure switch remain off forever, the filter is brand new, any tip will be super apreciated, thanks
A txv can fail several ways overfeed,underfeeding and hunting.And most are misdiagnosed. You need to look at evaporator temp super heat and subcooling plus Condensing over ambient.a liquid line restriction and TXV show the same symptoms.which are low suction,low head,high superheat high subcooling . Most techs think a bad TXV shows high head no!!! That is a Txv plus overcharge(two faults together)And a restricted filter drier will not always have a temp difference .There is only a temperature pressure relationship at saturation .Wgen you do see a failed TXV with high head it is do to a less seasoned tech adding refrigerant when he saw the low Pressures placing an overcharge on top of the failed metering device.this is why superheat and sub cooling need to be looked at .( now this comes with experience and knowledge)Not an opinion these are the FACTS!!!
No, it is an opinion....I have diagnosed txv valves this way for 20 years or more and have NEVER mis diagnosed not one....Of course there is common sense envolved with overcharging and such...It is still a mechanical device , not a computer...So go ahead and invest in 10000 dollars worth of meters when is NOT needed...The BIGGEST mistake I see techs doing is NOT connecting the high side when checking ,which is stupid..Thats how units are overcharged MOST of the time when the real problem is a restriction...Also, ice on one side or the other indicates a restriction in most cases...I have seen filter driers disenigrate and clog the txv...In either case ,both will be replaced...So , why the criticism?
TXV's suck! Do not get one. Nothing but problems. Just stick with a piston (wide open) design and you'll never have an issue. TRUST ME! Not worth the money.
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I had an issue where the suction gauge didn't move much at all after adding refrigerant but the head pressure did move a little bit, I was thinking a dirty condenser, I know you need more info but does it sound like a TXV??
Good day Sir. I just want to ask something. Here in Philippines, I have an upright freezer that I wanted to make the freezing faster. Can I use the TXV, to modify the speed of running refregerant. Thanks in advance for any info.
Thank you so much man. your videos help me so much, am new to the trade. And I love Refrigeration so much. please keep makings videos like this my brother.
High suction pressure, low liquid pressure, with low superheat and high subcool, compressor cutting out on thermal overload protection due to it being flooded, can't compress a liquid.
Great video. I actually had something happen a couple of time and I’m thinking it may be a txv that’s not 100% wondering what your opinion is. It was a series ac pro unit by allied. Subcooling was 9 but superheat was at 22. Delta t 18. Pressure 334 and 120. No airflow restrictions. Clean filter etc. any thoughts?
@@TaddyDigest one thing I should have added was for this unit and weather recommended sc was 6. I added more due to high superheat but as sc went to 9 sh barely moved. I went back to the attic thinking bulb was in a bad position but that made no difference. Do You still think add more?
Your pressures are actually perfect for R410a. Honestly I would slow the blower down to try and get a 20 degree delta T max 22 degree debts T. That can really help dehumidify the space more and help tremendously. I wouldn't add any more gas or adjust the TXV at all. 9 degrees of subcooling really isn't bad at all although you really should try to see what the target subcooling should be for that system. There should be a subcooling charging chart on that condensing unit and if there isn't then you can always download the check charge app and it will help you calculate your target subcooling and superheat.
@@TaddyDigest sir,it's my big opportunity if you can help me and,I have no experience in any other country,this is my first time, just in case,my plan to go there in Feb 2022,many papers need to complete
@@TaddyDigest thank you, I have a guy replacing it today, just wanted to see if he knew what he was doing. He had gauges and all, but I don’t know no difference of what I was looking at!!!
I’m pretty green as far as hvac goes. However, today I had an evap coil freezing up, switched the heat pump to heat, melted the ice, heat worked normal. In AC mode, my suction pressure was staying around 72psi and my liquid line was about 318psi, I tried to add some R410a to the system but the suction didn’t change, I recovered some refrigerant to see if it was overcharged the sub cooling and super heat seemed to be normal. during this time, the evap was building ice again. All vents were open, the return filter was not restricted and the blower motor was running normal. I’m pretty sure the txv is stuck but i didn’t grab the bulb or whack the txv. Coil also has a small leak, so I suggested to change out the coil. Am I on track or dead wrong? Thanks Tad I appreciate you and your vids, helps me a lot. Matt
I think you're on track if you check your subcool in your super heat If you ruled air flow as not the problem Then yes The txb could very well be stuck If it's not adjustable then replace it If the coil is leaking and you can get a coil and a t x v, replace i Make sure it doesn't have a fixed orifice if so just try to clean it out
I got a second opinion about the “bad” txv from another technician and he said the system wasn’t charged properly causing the ac not to cool effectively. How in the world can these findings be totally different?
@@TaddyDigest URDB Tad (dee best). Long story short: Neighbor’s condenser sweating and dripping water onto deck, SH(superheat) -2. I thought it was the TXV. A tech told me to seal the return air chase (air leaks from attic). I used duct sealer on the sheet metal edges and bam, SH 11, sweat on comp motor but not dripping on deck much.
Try adding refrigerant what happens when you do that Naturally it may freeze at the TXV if it's low of refrigerant if there's low air flow because the Kohl's dirty give more details let me know
@@TaddyDigest Thank you for quick respond . My boss air condition stop working he called the technician check outside condenser and he say everything seems to be okay with condenser . Problem must be with air handler which was close in the ceiling , difficult place to access I claim 40 feet long distance between two ceiling . 30 inches space between them . I opened that unit and there was no air filter . I feel like it was no high-speed air blowing and TXV expansion valve make some kind of noise . I was just guessing maybe bad expansion valve because make strange noise . Evaporator look very dirty . They want me to clean it . I have no idea how I take their pressure washer .
Taddy Digest I agree , I had a TXV failure yesterday , low side was in the negatives and high side was at 260 , superheat 100+ while subcooling was at 9...
hi have a york 3 ton unit it 28 year old i do all maintenance it has a 6 in air fliter n uv light kill the mold keeping coil clean n clean outside Conditioner to . the compressor leaking oil but no puddles just wet look. today is 102 F 6-6-24 SO How much longer will have cold air this start it last year . i am surprise still got cold
