How hvac technicians diagnose bad TXV problems in the field?
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- Опубликовано: 26 сен 2024
- TXV KNOWLEDGE
In cooling operation a bad Thermostatic expansion Valve could cause the suction pressure to drop to 0 PSIG
It could cause the head pressure to rise upwards of 500 PSIG
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#txv #hvac #airconditionerrepair #heatingventilationandairconditioning #hvactipsfortechnicians
Dude love what you’re doing thank you. I think the TXV is the biggest mystery to new guys to the industry. Great information brother
Thanks man I love your name wizard slayer that is awesome
Thanks for watching my video
I appreciate your time please share
@@TaddyDigest you are great sir thank from india
Thank you my friend
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
I've watched 5 videos but still couldn't understand it until i come across yours. Thanks for the info
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
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 !
Simple and straight to the point..
Thanks on high side pressure was going from 300 to 600 unreal you got it
Most companies have a chart inside the control panel with superheat/sub cooling specs, use it. I always used that information when I was working.
PT charts and slide charts work great I agree everyone should have one with them at all times and use at all times
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.
More to come!
Good shit good explanation on everything you just earn a subscriber
Very cool glad you watch thank you for commenting and subscribing
Let me know If there's any specific videos I can do to help you
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.
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?
I'll tag you in a video
Where I had this happen
Best way to explain
@@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.
Wow great explaination simple easy and catchy ... thank you keep the good work
you are welcome 😊
Taddy appreciate your videos bro good job 👍. Can you make more hvac videos like this!!!
your welcome my friend
Yes I can
what specifically would you like me to make videos about
More on subcooling, superheat and using multimeters on a c unit.
ok deal
The suction pressure is 125 And high side is 400 and 5ton unit is not getting cold. Unit was serviced also
Thank you 🙏 I think this helped a lot!!
It's awesome so glad that this helped so glad that you watched thank you for watching
Nice job 👍 I hate txv Iam a fixed piston kind of guy.
Totally understand
Thanks for your support and the wonderful comment
Most units are txt now. It may help to get used to it.
Your Absolutely Correct my friend
Keep'em coming brother, new subscriber
Awesome so glad you're here
Thanks for sharing your knowledge and idea sir.
Your welcome
let me know if you need me to do a video on a certain subject 😉
I love watching your videos man you're the greatest
Glad you like them!
Awesome explanation
Thanks Brody
Great detailed information
thanks Mario 😊
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
Glad it helped
Very
helpful information
So nice of you
Thank you for your informative video. We are a manufacturer of insulated copper pipe and other HAVC parts. Our prices are absolutely reasonable, if you need anything, feel free to contact us.
let's collaborate send me an email tadfuller1@gmail.com
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!!!
TRUTH.. Thanks for sharing this homie
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?
@@groovee63 you can use a manifold and k type temp clamp from your meter. Why would you say you need exspensive tools?
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.
@@donaldallen743 What? Stuck TXV?
Great video keep it up very informative 👍
Thank you Bob 😊
how did you know you didn't have a leak instead of a bad txv ?
Recover and weigh out the charge
Very informative video
Glad you liked it
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
@@TaddyDigest ok thanks for responding Tad! Matt
Good afternoon Tad, TXV fixed it. Thanks again.
@@TaddyDigest Good afternoon Tad, TXV fixed it. Thanks for always answering dude, I appreciate that. I don’t work for any company, I’m a one man show.
high heat breaks down oil.
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?
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….
that is crazy sounds like a rip off to me
Thanks
You're welcome
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?
What the unit does when it's a restricted
I just checked a unit today and the suction line it’s 0 high side 260 psig and the fan and compressor still working ?
⭐️⭐️⭐️⭐️⭐️ Five star video.
Thank you my brother
@@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.
Good video. With expansion valve don't you set your refrigeration charge with sub cooling and not SH?
yes
I just had my hole unit replaced and it’s a Goodman and the split is only 11 I have it set on 68 and the air out the vent is only 57 so is that good
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.
@@TaddyDigest ok thank you
Hey, baba I was wanting to know your thoughts on Press Fitting instead of brazing. It seems quicker.
Thank you Taddy for your informative video. In the capillary tube if it’s blocked will be the same scenario? Thanks.
Yes same thing
Thank you for watching
I like the way you explain how TXV works.
very cool glad this was helpful 😀 😊 Thanks for watching wade
Please share my friend
Did you have to recover the refrigerant before replacing the TXV? Or it was there in the condenser because obstruction
yes always recover
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??
Definitely need more info
Liked and subscribed
What if the expansion value stuck open?
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.
How could we know how much refrigerant charge Sir?
Check the service fax on the side of the equipment and you will see it gives the factory charge
nice video
Thanks
What if txv stuck fully opened ?
What pressure will it be?
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.
You can use the TXV to modify yes
I don't know if that will help you to make the freezing process faster
Will bad txv lead to suction pipe frost ?
yes
Thanks sir lanka
your welcome my friend I am very grateful for you watching this
please sub and like and hit the bell
Jackson Jose Anderson Gary Hernandez Angela
Don't blame txv , if you change filter dryer , it will resolve the issue
yess 👍
Risking 2 evacuations and 2 charge ups if it's on the condensor. Good idea to change both.
Can a bad txt valve cause the compressor yo kick off too??!
It can caus the suction pressure to drop to 0 and caused a low pressure switch to open shutting the contactor down and therefore stopping compressor
@@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!!!
Thompson Charles Lopez Jose Taylor Melissa
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?
Add a little refrigerant
I think that could be the issue
@@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.
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
I hope it lasts many more years
@@TaddyDigest hope so to n got my 10k ready for new so you think the rust got to compressor that why have wet oil
I have a situation, suction:64 4.6(SH), head:267.2 39.3(SC), in a R22 system, is it overcharged ?
could be dirty condenser coil or restriction or overcharge
is the coil dirty
@@TaddyDigest condenser is clean
could be over charged
what was indoor temp
What if one side of txv frozen?
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 Thanks, yes was just low. I had worried there was a restriction at txv. Thanks
Hey Chad glad you figured it out
It's always simpler than we think
Have a blessed day
What will happened with the suction pressure when expansion valve was stuck open ?
suction pressure goes up if stuck open
@@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 .
I was quoted $600 to replace txv on my six year old carrier unit? Does that sound ok?
yeah usually around $500.00
but it depends on how much refrigerant too
I would say no more than 600 for sure
highest one I have had was $525.00
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?
@@dewayneoverton466 Let me know when you are watching my channel and I will do a live stream for you and talk to you about it.
Tadd.. on my home system.. Superheat is 48° / Subcool is 10°.
Hey my brother thank you for joining please send me an email tadfuller1@gmail.com
Sure hope he cleans that condensing unit coil with all the grass clippings he could cause high head
Unit is working good and yes I did clean the coil thanks for watching
Sir I'm Filipino,can you help me to work there?
Hey
Thanks for watching
I don't know if I can help you to work here or not
Not sure what you might need
@@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
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.
RG After you get some experience in the field you will understand Thanks for watching
I appreciate your support
Young Carol Williams Nancy Young Michael
Allen Jessica White Paul Davis Brenda
It’s all wrong. TXV failure usually will give 75-95 pressure and superheat that won’t drop below 40. Your subcooling will be 3-30
John more experience will show you many circumstances in the field Its a learning process.
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...
Thanks for sharing that with me JP
I appreciate you
Experience is the Key 🔑 my friend
TXV's suck! Do not get one. Nothing but problems. Just stick with a piston design and you'll never have a problem. TRUST ME!
hahaha 😂 Yup That's right
< 💦
Jones Ruth Anderson Mark Williams Barbara
Do u have to calculate superheat still if u have a txv i thought it wasn’t required only subcool since it has a txv ?
It's good to calculate to know if the coil is starved or Full So it's still beneficial I would definitely do it always
Great
Great for help
Thank you for watching
Hello sir , how about my system may ubcooling i got is around 12 is that okay or over charge ?
sounds good 👍