Troubleshooting the TXV

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[@randyfalkosky8579]

30 years and this is the first time I have seen a TXV tested this way. Very cool !! much easier too.

[@DjDg-x5n]

Pulling the bulb away is an immediate indicator as to the operational validity of that metering device. Thank you for being well informative.

[@rodgraff1782]

Way back in 1973, at the US Naval school of Air Conditioning and Refrigeration, I was taught that the function of a TXV was “to meter the proper amount of refrigerant according to the heat load, and to maintain superheat. I still taught that to my apprentices until 2019. Your presentations are the best that I have seen in my 45 years in HVAC, both as a field service engineer and apprenticeship instructor. Keep the videos comming

[@P9rkour90]

Wow you’ve been in the field for many years and I’m sure has worked on many different kinds of unit! A lot of experience under ur belt! 👍

[@josephsomeone1611]

Yes sir, not a HVAC tech person; I did the compressor fan removal wire test for the TXV on my 4-ton Trane system. I took the purple wire off of the run start, common capacitor, rather than the contactor as shown by you in U-tube video. The contactor was more difficult to reach than the purple wire on the capacitor, same result, the fan stopped turning. I watched the low side pressure stat within 5 to 10 psig of the original value while the head pressure went to 300psig. A very smart way to check the TXV, thank you so much for the demonstration! I was not looking forward to taking the plenum apart to get to the air dryer and the TXV bulb to test them. Thank you Sir, regards Joseph

[@GRJCLyon]

I’m sure compliments on a video that is a few years old will always be appreciated so here is another one. Thank you for making this great video. This helped me a lot while diagnosing my sweating liquid line. I wasn’t sure if it was a txv problem or a restricted liquid drier. This will help eliminate me opening up the txv for no reason. Kudos to you for your knowledge. Thank you!

[@hvacservicementor]

Glad you enjoyed it!

[@blackericdenice]

I’m a truck driver and I decided to replace my evaporator and condenser myself. I will try this when I get home.

[@marconantel7735]

Incredible. I never heard of such a test, great info!

[@michaelcostello6991]

This was a super !!! video. You get to test the TXV without pulling things apart and risking doing damage. Thank you.

[@martingates6501]

But you don't need to test a txv when everything it's ok, if the system is operating good, it's not necessary to do this

[@jeraldlockhart2046]

That all depends on if the airflow is correct and the line set is correct and there’s no kinks etc..❤

[@yodamanrulz176]

I, too, have been an instructor in several different fields of technical ability. I appreciate your demeanor and your soft-spoken direction. I aspire to that myself. Thank you for not using a big fingers and elbows two point stuff. Clear minimal pointing perspective are optimal. Thank you very much. Hope to perhaps meet you one day and shake your hand. Best wishes to a consummate professional.

[@mbahcarrier1629]

Thank you for the knowledge, success for "HVAC ......." ... Pekalongan, Central Java, Indonesia attended

[@nunezravelin3898]

Excellent video. Simple way to test a TXV. Thanks a lot for sharing this knowledge!

[@wasifaliwasif]

Congratulations you are passed . You are the one who understand " the action " in a Refrigration cycle.

[@l.crossjr]

Top notch explanation and with field example 👏

[@alexsilyaev1593]

I very rarely write reviews but I decided to write you are truly God in this industry TNX!

[@La2venida]

nice information. Also, instead of removing the bulb. can you just take a hot/warm towel and put it over the bulb and likewise for a cold check.

[@jascam1]

Excellent video, I'm electronic tech (voice/data) but not HVAC, now I know what to look for when the HVAC tech shows up. They just replaced TXV on my new ( 6 month) Goodman Heat Pump with a piston.

[@nsudatta-roy8154]

Wow! Why in the world would they have done that? Sounds like you had zero comissioning on your system at install. Was it done at both the indoor and outdoor units? Also, sounds like you no longer have a valid warranty. There's a reason why the industry is moving away from fixed metering. Swapping out the TXV presents a problem for the next guy who comes to service your unit and rely on the manufacturer's "plate."

[@mrfaulk7739]

Great video not trying to over complicate things so only certain mindsets understand would be a great HVAC instructor

[@mrfaulk7739]

Many college professors can't get that when your dropping $100,000 on an education you deserve to learn how to do the job ...

[@vanhogan5483]

Thanks you so much coming from a new tech.

[@hvacservicementor]

You bet!

[@elgringoec]

That was great, Eric! Highly informative, well delivered. But am I in trouble??? I'm not a professional HVAC technician. Nor have I ever been to HVAC school. But I do have a manifold gauge set. Couple, actually. And I did take and pass the EPA certification and have a universal rating. Fwiw. But I've been doing my own HVAC since before the certification idea that came about as a result of the govt forced elimination of R22. I hope that lets me participate. 😂 I followed you fully and really appreciated learning this method of checking TXV operation.

[@BlackDynomight]

Very well explained, thank you sir.

[@GustavoGutierrez-tn7ef]

Very good video, thanks very much

[@texasacandheating5563]

This is the best explanation ever, 👏 thank you very much

[@hvacservicementor]

You're very welcome!

[@dawggaming-fi3pm]

This is a informative video that will help me a lot,related to my job .thank you so much for sharing your knowledge 🙌

[@davidwillkomm3484]

Thank you. I had to take a 32 oz wide mouth filled of ice water and ran back to the condenser to see if the txv was bad. It was. This is a better method. Like a professional instead of asking for a cup of water and running around to the unit.

[@garypoplin4599]

What a jewel! If you were a betting man, you’d win the bet every time that I’ll be using this trick for the rest of my career! Thanks for the _great_ content.

[@hvacservicementor]

Thanks, Gary!

[@exclusive_148]

if its bad whats going to happen at the suction pressure? It will go up?

[@frankduarte7109]

You are the man.. so what would I expect to see if I upped the head pressure with a bad txv? I see with a good txv the low side stayed the same

[@hvacservicementor]

Suction pressure will rise with head pressure because the TXV is unable to control it.

[@jericosha2842]

That's a really good test and explanation. Thanks for sharing.

[@petroman-cg8tt]

Great Video Joe H Navy Seabee

[@maxpigeon]

"You can't watch the sensing bulb and the suction pressure at the same time." *Job Link probes have entered the chat*

[@hvacservicementor]

That's a good one! meanwhile, by the time you have taken those fancy gadgets out of their padded case, and done all the work to dig the sensing bulb out of it's home, and put it back nicely and fixed all the armaflex and cork tape and mastic you had to remove to get to the little bugger, the tech who followed this advice is already paid and on to the next job or at home with their family at a decent hour!

[@zesty2023]

@@hvacservicementor oh fuck, burn XD

[@philklassner2815]

Excellent Demo. TY

[@davidwhite3338]

As a DIYer it appears to me that this is a good test and absolutely worth doing but it is testing the valve and balancing spring only. The bulb is not checked as to whether it is responding to temperature change of the suction line as the conditions change for the evaporator coil.

[@hvacservicementor]

Keep it up!

[@joecooksey4331]

Excellent. There are plenty of HVAC videos that don't use this test.

[@str-1-u5u]

Hi, I maintain over 100 Rheem package units at our resort. The other day, I responded to a call where water was leaking into the ceiling. When I arrived, the evaporator coil and compressor were covered in ice. There is a lot of debate around the shop as to why this happened. Airflow was okay. The coil was clean and after thawing everything out, the blower motor didn’t have any problems pulling the filter panel closed on it’s own. Some of the technicians believe that the doors to the room below were the cause because they were open to the4 hallway, even though the hallway was being cooled by another package unit. The high side gauge was only about 10 degrees above ambient (104 / 115), and the low side gauge was around 42 degrees. I’m accustom to seeing the high side gauge around 30 degrees above ambient. The compressor was pulling 15amps on all three legs and the condenser coil was clean. I moved the TXV bulb outside the unit, and nothing changed with the low side press/temp which made me pause. Adding refrigerant didn't change anything either. There was 6 degrees superheat and almost 0 degrees of sub cooling, but package units are difficult to make accurate measurements because all the components are tucked away in the cabinet. I think something is wrong with the TXV, but I don't know how to make a positive diagnosis with a package unit. The other technicians believe, that the coil can still freeze even with 75 degree air is flowing through it. Any thoughts?

[@larkhill2119]

What are the temperatures on the filter dryer? Did you nail the problem?

[@curtisdupre5194]

Thank you❤

[@thomasprice7266]

thank you for this video been looking for a good way to test

[@heatingcoolingstuff]

This is a great video. Thank you so much.

[@alvinobalan2320]

So this is mean ser that the txv. Was working very good..thanks

[@heatingcoolingstuff]

This is a great video. Thank you. This will help me a lot.

[@josuelujan7736]

Thanks for your help.

[@tonydelgrego2906]

Thanks That is an easy way to test it.

[@YTsux24-7]

Brilliant, simply brilliant. 👏 Does blocking the intake or discharge air produce a similar result without removing live wiring and potentially shorting out something, like my lifespan?

[@hvacservicementor]

Yes it does, but the effect is not quite as dramatic depending on how effectively you can block the air flow.

[@John-dp3ln]

Great video great instructor.

[@wasimedoo7994]

Very good information bro on that TXV so what you saying if your gage did not respond when you stop the fan it clearly saying that your TXV is not working thanks you God bless keep it up

[@petesingh292]

Great video, if TXV is bad both pressures should up when cond.fan disconnected and if TXV good only head pressure goes up? And suction remain same. Plz do reply , blessing from CA

[@claude77573]

You can also test to make sure the TXV is opening by going the other way - cooling down the liquid line and reducing the liquid line pressure. For example, on a hot day, run water over the condenser coils. It doesn't take much. Even a decent "mist" of water with good coverage over the condenser will do, and may be better as the fan doesn't have to move a large mass of water through the condenser coils. This cools the condenser, which reduces the liquid line pressure (aka "head pressure") . You'll see subcooling drop as the saturation point of the refrigerant in the condenser drops, and it drops at a rate faster than the liquid line temp, thereby reducing subcooling. In effect you are replacing refrigerant subcooling with water evaporation cooling. If the TXV is operating correctly, it will keep open up in response to the reduced high side pressure to maintain superheat - as long as there is enough refrigerant in the system to keep the condenser and evaporator adequately filled on a high load day. MesureQuick will tell you that pretty quickly. Then again, MeasureQuick does not understand the misting process. If the superheat goes up to, say, 25 due to a low refrigerant charge, it may report that the TXV bulb is stuck closed or the bulb lost its charge. By the way, the make mister kits you can mount on condensers. For example, see Cool-N-Save, coolnsave.com/product/cool-n-save-ac-misting-kit/.

[@hvacservicementor]

Any way to create a fast and dramatic change in head pressure will provide a good test on the txv. Dropping pressure quickly may have the unintended consequence of also dropping suction pressure which can create confusion. If that works for you, that's great. I have seen a garden sprinkler set up as a temporary remedy when a condenser fan fails on a multi-fan commercial RTU plenty of times.

[@chrisscott1547]

Wow! Great method, and great presentation!

[@mark.r8900]

Would the results looked similar if the txv is stucked closed? Great video. Thanks

[@hvacservicementor]

A TXV stuck closed will show very low or zero suction pressure with very high head pressure, often to the point of opening the compressor's internal pressure relief valve which will then cause pressures to nearly equalize.

[@floridacooling9669]

Good stuff. Thanks for sharing!

[@abcdefghi2175]

pretty neat trick learned something today thanks!

[@adamsonnyau4844]

Great lesson dear,.,.,. easy to follow explanation

[@anvibrimel41]

Thank you very much teacher

[@johnbipper4601]

Unplug condenser fan and watch suction pressure, it should have little or no change if the TXV is metering correctly.

[@neutrodyne]

Wow. That is a great tip! Thanks!

[@davidgearardo1788]

as a new tech here, that shows that the TXV was operating properly, if it was bad would my suction line pressures rise as well or decrease?

[@hvacservicementor]

If TXV is frozen in some mid position, it will behave like a fixed metering device and suction pressure will rise along side the head pressure.

[@Kevin-mm6xm]

I too enjoyed the video but I didn't get the definitive answer on the TXV being good or bad. I hear "stuck in one spot" bad, but then I hear in the comments "stays in one spot, functioning properly" which is what a TXV is supposed to do, keeping the superheat constant. I'm subscribing because I think you really know your stuff! So in this case, was it good or bad? Thanks

[@hvacservicementor]

It would be more accurate to say "stuck in one spot, not functioning properly, but still delivering performance that is good enough for the customer to not notice the problem in spite of the fact that it is technically broken". Hope that helps! The TXV in the video is perfectly fine.

[@countryfriedhvac]

Great video. Thanks.

[@Danny-pp1gk]

During this test test (ie raising head pressure) if pressure remains the same then TXV is good. What would bad look like. How much change in the suction pressure would be considered bad.

[@xincai951]

Is it possible to have a functioning TXV, ie maintaining superheat, but superheat is high? Check liquid line temp between condenser and evaporator, about 1F difference so no restriction.

[@theprofessor5584]

Great video, but i had an issue where the walk in freezer coil was not doing a good job cooling the space, superheat at the evap was 39, Suction pressure 17psi, i had to charge the unit to get proper subcool values, how cam i use the information in this video to diagnose a restricted txv? I know this video can indicate if a txv is stuck open but what about an restriction where the txv cant allow much refrigerant through? I already checked across the drier and other places

[@hvacservicementor]

This video is exclusively meant to test if a TXV is vunctioning on a high - temperature air conditioning system. The techniques mentioned in this video are not able to diagnose a restricted TXV by themselves. A restricted TXV and on that has an improper superheat spring adjustment will behave th esame way. Restrictions are one of the most difficult things to diagnose because other problems will create similar symptoms. While refrigeration systems also have TXVs, they experience a lot more dynamics than an air conditioning system. They are different enough that I consider them to be completely different animals and none of my training is meant to address refrigeration systems.

[@nasserahmed583]

Great video! Thank you for sharing your experience and knowledge. When TXV of my AC was warmed up the the suction pressure increased and head pressure went down. In this moment case, Does this proof the txv is not faulty? The problem is 48 F superheat and 20 F subcool and when txv was warned up both supermarket and subcool went down. Thank you in advance for answering my question.

[@jx5hficus176]

I think if you have to force the TXV open no matter where you put it , it's a bad TXV, it's unable to work by itself

[@ronchambers9762]

Thank You.

[@hvacservicementor]

You're welcome

[@melquesedekcastro7480]

That's simply great, I only feel bad, that I never thought about that before.

[@bangtwister]

Thanks

[@ParabellumX]

(11:25) Either that's an R-22 unit, or that evaporator coil was freezing. Love your videos.

[@hvacservicementor]

Yes. R-22.

[@keovongvilaykeo4799]

Great information thanks you always

[@watchandlearn23]

Thank you I learned make more videos

[@jodanypaul9382]

Hey man I just saw that video in that case to say that you have a bad txv in that scenario the suction line pressure had to raise up as well? This is a great video man can you tell me in that scenario the txv is doing his job?

[@JR-ch8rt]

Thank you for the amazing video 👏

[@roberth7559]

very nice - you speak, ill listen

[@alexluna6810]

The compressor will go into thermal overload???

[@Yodaddynyomama]

Bro! Excellent! Great video! You have made my life easier!

[@JT-rz9he]

Best every!

[@fahq6703]

Great video!!! Thank You.

[@soloch69]

Great video love it, I was trying to long in to your website but it was not letting me

[@hvacservicementor]

site was in transition go to hvactraining.squarespace.com/

[@jayjasso5604]

Great video !!

[@hernanjoseprietoherrera4839]

Hi , can you show us troubleshooting with Piston? Thank you.

[@woodworkingfan1965]

So if I’m testing a TXV on a geothermal heat pump, I can switch to heat to effectively do this same test?

[@hvacservicementor]

No. Switching a Heat pump from heat to cool during a cycle will upset everything for a few minutes until it reaches a new equalibrium. This test should be done when the system is in cooling mode and operating in normal equilibrium and has achieved steady - state operation after running for at least ten minutes.

[@WesternReloader]

What if I buy a replacement TXV, that was R12, and now the only available is 134? My system is still R12… will the value of superheat be incorrect?

[@smacleod69]

I do a lot of maintenance calls and if the system is cooling pressures look good. I am not going to open up a can of worms. If that txv is stuck and acting like a piston and there is no problem with cooling. l et it go!

[@hvactech5829]

Thank you Master !

[@fascistpedant758]

@1:54, I've had the 1968 edition since the late '70s.

[@alfonsobenitez8574]

Can i disconnect the brown cable at the capacitor with the power off, and then turn on the unit after securing the fan brown cable so it wouldn't short out, then turn on the unit? Would that work as well, i only have my right arm and don't want to take any chances. Thank you.

[@bongbutingting3838]

Thanks very informative. Is this also applicable to a watercooled condenser?

[@gigi644]

yes you close the water valve

[@VincentCiani]

Great Job😊

[@hvacservicementor]

Thanks 😁

[@phillipjoy8191]

Good job 👍

[@ericmodernel9205]

Great Video

[@stevealoia]

I have a 410a unit m trying to figure out . If it the txv or not . Low side is 158 Psig with 17 sh and 288 psig on the high with AC if 1.4 Would the txv be bad thanks

[@Dontleavemedimi]

So Eric would it be safe to say that if you have an irregular amp draw that txv could be in the culprit category along with dirty filter slow running fan in or out and some other restriction.

[@hvacservicementor]

If your TXV was slammed shut, you may have high compressor amp draw, but that would be the least of your problems. The internal pressure relief would probably pop before you got your amp clamp out. Most of the time, any condition that reduces refrigeration capacity (less cooling) will have a slightly lower amp draw including the conditions you mentioned. Difficult to perceive unless you have a "before" measurement to compare to. Remember, compressor amp draw will vary along with cooling load.

[@Dontleavemedimi]

@@hvacservicementor thaNks for the insight..

[@alvinobalan2320]

Did you off somthing to test the low side guage...ser.

[@michaeljoseph4392]

Thank you

[@hvacservicementor]

You're welcome

[@erniemanaog5377]

Woow thank you its a big help

[@nilbertocohen4963]

In this case the txv valve was good or bad?

[@hvacservicementor]

It was good.

[@falfighter]

will a bad txv cause over amping?

[@hvacservicementor]

A TXV that is slammed shut or mostly shut will cause the head pressure to soar and can cause higher amp draw on the compressor. In that case, it won't run very long for you to take a meaurement before the internal pressure relief opens and the amp draw drops very low.

[@jpechacek80]

Is the procedure the same for heating with a heat pump?

[@hvacservicementor]

In cooling mode, yes. I wouldn't bother with it in heating mode.

[@gorillaxrich]

Pure gold... I'm talking 24K...

[@NadeemKhan-xu9pk]

Please explain the head pressure about other refrigerant. (I believe head pressure situation r 22 explain ) Thanks

[@shine-cg9uf]

👍💪🇺🇸❄️ Great information. ? Would this work on a walkin box with a pumpdown system with a liquid receiver n solenoid valve ?

[@lesliedaisley7846]

Can this work on a Commercial Refrigeration Systems, Racks and Ice Machines too?

[@maazahmed86]

If there are multiple evaporators connected with one single compressor, how do we check each of the txv's.

[@hvacservicementor]

That is very tough. Very nearly impossible.