Troubleshooting the TXV 

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

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

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.

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

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

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

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

Thank you I learned make more videos

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!

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?

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

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

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

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

I dont trust this guy.. he still has all his hair

I like him😅

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.

But... The condenser is not condensing without the fan.. you are feeding hot gas into the txv.. how are you testing to TXV when you are creating a fault for the TXV to not work properly?

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

So if I wanna open up the TXV I should pull the lead off the fan motor inside so that unit freezes up instantly that should lead in a dick ton refrigerant😢😂😊 huh lol

Taylor Jose Davis Elizabeth Lopez Patricia

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!

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

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

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.

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

Very well explained, thank you sir.

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

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.

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

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

Credit this guy is a celebrity. I'm I the old van or house or attic and need quick info. Redo 3 times. Distill until 4minuts 20 seconds to inform over worked underpaid abused technicians hopped up on coffee and under stress to perform like a master or lose money for thier family business.

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Couldn't you just spray water over the condenser as well?

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

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

Taylor Donna Taylor Karen Williams Mark

This is a great video. Thank you so much.

Top notch explanation and with field example 👏

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I'm figuring that was an r22 system

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

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?

In this case the txv valve was good or bad?

But why was your saturation temp so low? About 15 degrees assuming this unit uses 410a that’s well below freezing 🥶

Thanks That is an easy way to test it.

Thts a way to burn the fan 50 percent voltage disconnect the cap. Safer too

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.

I was told at school to go by Subcooling 3* +~ whatever the condenser data says

Great Video Joe H Navy Seabee

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?

Also, where do you actually find cold iced water or hot water?

Usually for me that's when the spade pulls off

Tnks for the Disclaimer.....funny but true😏if u do not own a set of Gauges,,,,,,,,wow. So right in the Money

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

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?

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

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

Thank you very much teacher

i thought you're going to manipulate the indoor fan, is it the same?

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

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

Thanks

Great video great instructor.

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

Thanks for sharing knowledge. Great video.

Best every!

I keep a roll of 30 gallon trash bags on my truck for this type of TXV test and checking/charging heat pumps.

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

What if it is a walk in freezer and it has a headmaster control?

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

will a bad txv cause over amping?

Thanks for your help.

Nope the way I test one is if your suction side gauge is sucking down that the first sign of txv problem if you pull the wire off the reversing valve if the pressure are correct then the txv is going bad and sometimes the suction pressure will pull all the way down into vacuum but head pressure is good

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

i could have used this trick....had a unit that i thought had leaky shrader valve and it did so i replaced them ..recharged and all was well for about a week..i go back and im thinking there has to be a leak somewhere so i tear everything apart ...cant find it with the sniffer. ..i call one of the more experienced techs and long story short it was a bad TXV ...

That's why they have Bluetooth gauges!

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

cool intro lol

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.

Great video. Thanks.

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.

Good stuff. Thanks for sharing!

Thanks sir,,

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

Thanks you so much coming from a new tech.

Wow. That is a great tip! Thanks!

Why do all this comments seem like the dude payed for them?