Craig from AC Service tech joins us and shares some of his knowledge on TXVs and shares his concern about techs swapping them with pistons.
Visit AC Service Tech website at: https://www.acservicetech.com/
Find Craig's channel here: @acservicetech
Read all the tech tips, take the quizzes
and find our handy calculators at https://www.hvacrschool.com
Visit AC Service Tech website at: https://www.acservicetech.com/
Find Craig's channel here: @acservicetech
Read all the tech tips, take the quizzes
and find our handy calculators at https://www.hvacrschool.com
Does anyone know of a electronic expansion valve where the controller will allow you to run the suction pressure into a vacuum without faulting? Also the Sporlan controller I was using would fault out below -59F. I had to run the controller in manual mode so it wouldn't fault out then I had excellent control metering the refrigerant into the evaporator. At -85 degrees I can be running a suction pressure 25 in of Mercury. Single stage ultra low temperature chiller with subcooler
Pistons never fail but TXV‘s or more soothing to the system Service area Nepean??
My newly installed Gman 3.5 H/P sweats on the A/H housing and a lot of water pool under the condenser. The tech replaced my TXV with piston in the attempt to rectify. The H/P works fine otherwise, what's with the extra water??
I have to disagree. On a residential single stage system there is absolutely no need to have a txv. It's simple, less moving parts equals less things that break. I have a piston on my system and it cools my home just fine. I see bad txv's often and it's unnecessary to have one on a residential ac system.
Thank you. Question? What is the allowable temperature drop across the inlet of txv and the outlet of it
Is there any harm in using both together? That way if the Txv ever fails, the piston is already there to prevent what problems arise from the failed txv. 🤔🤷♂️⁉️
Just happened by your channel (Thanks YT), I have a question in RE to the Bulb not making the best contact, would a thermal grease/patch, like what is used on CPU heat sinks, be a way to better improve contact between less than straight surfaces?
I recently installed a R410a 3 ton system with 60 feet of line set. The manufacturer of the condenser calls for 8 degrees sub cooling, but the TXV manufacturer calls for a MINIMUM of 10 degrees sub cooling at the TXV valve. I went with 11 degrees at the condenser and everything works fine and is in spec with their performance data. My question is should I have gone with the condenser 8 degree or the TXV 10 degree or does it matter at all? I'm assuming that by the time the liquid line travels 60 feet it has cooled even further so maybe 8 degrees at the condenser is ok? HeLp!!
WHAT ABOUT A CHEAPASS CUSTOMER WHO DOESNT WANT TO PAY FOR TXV OUT OF WARRANTY. Piston is good enough in that case. You mentioned nothing about pricing. I'm giving you an 80 on content. You barely passed boys, lets do better next time, ok? Service area Barrhaven??
Great job and video like always
I've done it multiple ways. Replaced TXVs with pistons and vsversa. All comes down to the situation. I've also cleaned clogged strianers when other techs condemned the valve.
Never heard of this problem. Only complaint i have is difficulty finding amount of superheat required. 10° when in doubt has served well.
Wow you guys are super neurotic I dig it
Im in california and in 17 years i only replaced a handful of txv's. Most times it wasnt installed properly and i just had to strap them in the proper position.
I still don't get the equalization line job, if the bulb got warmer it will push the needle down to get more refrigerant, but now the equalizer tube will get more prussure and it will be pushing the needle back up !!
TXV is good for refrigeration not A/C after 105 they suck. FACT
General question. What issues if any would be created the TXV installed upside down?
I would have liked more info on the piston and what it does and why the techs use them in place of the txv.
Excellent
Why techs need to stop replacing them with a piston wasn't covered. The simple reason to use a txv is that it's better. Service area Kanata??
I have to tell these guys I get what they are saying, but I’ve been know to use a piston in place of a junk txv. As long as you use the rite piston and the system is working within peramiters it’s fine to do that. I don’t do this on newer systems, in a pinch I’ve done it on old systems that it really didn’t matter especially when you have a customer who is cheap. I carry all sizes of pistons,
maybe someone can give me their opinion on this ,,,,,ok i am retired age 67 i have an old heat pump that i keep in as good shape as i possibly can ok ,,,,i have r22 in storage about 50 lbs of it ,,,,i was wondering if it would be worth while to buy a 410 A system change out the txv for a r 22 and go that way ,,,,instead of dealing with a high pressure not as good as r22 ? thanks for all your teachings its all good anytime ,,,, Are you in Nepean ?
Don't get me wrong. I understand that a correctly working TXV is better than a piston. My problem is I see a lot of TXV's that are poorly performing but not bad enough to justify the cost of replacing. A few years ago I went to a rent house with a 4 year old Payne unit with electric heat. It was a insufficient cooling call. Had high subcooling and superheat. I replaced the TXV after driving across town and waiting in line at the Carrier dealer. About 6 months later I get a insufficient cooling call from the property owner. Same condition as before. Replaced TXV under warranty this time I eat the labor, etc. Less than a year later, same damn thing. This time it got a piston conversion and I haven't been back since. Now when I replace a TXV I make it abundantly clear that the labor warranty last until my tire makes the first revolution. I always flow nitrogen when brazing and use good a evacuation process.
I think a lot of older techs, or really, techs who don't like TXVs are just writing themselves out of a job. TXVs are basically the new normal, even for standard efficiencies. They typically work much better than pistons, all these failures? Lack of vacuums, to be quite frank. I've seen it happen, where guys pull a 10-20 min vac or do the purge. Of course pistons will survive, but not TXVs, nor the longevity of the unit. I used to be afraid of replacing TXVs, then I discovered the hot block or viper wetrag, made easy, done easy, pull a good vac, and I ain't ever back to replace it.
Had 1 txv fail that I put in, in 40 years but have seen installers from different companies purge lines with freon and not use vac pump when installing new equipment. Are you in Orleans ?
Sporlan Parker expansion valves are junk. I prefer and put my faith in the Emerson Alco brand. They have a stainless steel powerhead that does not rust like Sporlan does. Also Danfoss makes a nice txv but much more expensive than Alco.
Please calling it a TXV its properly called a TEV
Another argument against zip tie is that they won't conduct. Although minuscule a metal/copper clamp will help conduct temp into the txv bulb
Reason i think a lot replaced txv because the quality is a lot of made in china junk. Sporlan made in USA was a good txv .
Great video! The other thing that makes Txv superior to a piston is that it can open more during hot conditions to let in more refrigerant than a fixed orifice could.
Great video! The explanation couldn’t be better 💯👏. Since the contact area between the TXV sensing bulb & coil outlet line is not optimal (because both are round-shaped), I think adding thermal paste could improve heat transfer for better temperature sensing. Kind of what happens with temp sensor probes & thermowells.
The problem I have with them is that their theoretical effeciency improvements don't line up with reality. I replaced the TXV in my own system with a piston, and comparing before and after runtime data on days of the same temperature I'm seeing a 2-5 percent loss in efficiency. Considering what I spend on cooling here in southern Michigan that's $15 a year. One service call on a TXV and any cost savings it gives the customer over the life of the equipment is gone. Not worth it. Now if I was in Florida or Arizona and I'm running my ac all day, all year I could see the advantage, but for people in the Northeast, Midwest… doesn't make sense.
Well done !!
Thanks for the knowledge
If I replace a a-coil that has a txt on it I replace it with a piston coil. No problems here
Awesome video thanks again. Will share with the new guys at the shop
Great video!!! Thanks for teaching
The industry doesn't braze with N2, a reality many places. I saw it. Pistons are less sensitive so… Now I use N2 but I am sent to do electrical, too slow in others opinion.
TXV FUN FACT: The average maximum TXV valve's pintle pin 'lift'/opening size is only 0.200 thousandths of an inch. MAX!
Now think about just how SMALL the opening is during NORMAL operation. SMALLER!
How important is a good clean refrigerant inline filter NOW! (A TINY foreign object can RUIN the whole show!)
0.200!!! MAX avg. TXV OPENING! No MO!
Put that one in your pipe and SMOKE IT!
Great lesson.
Is the expansion valve normally open or closed position when system is off?
Great team up!
WOW 2 Juggernauts of the Rap, i mean Hvac game! Love to see this collab. Very nice. I follow 2 of u guys.
Nice man!
What is TXV !!! Are you in Barrhaven ?
Thank you so much 2 Masters HV-AC SOLUTIONS 🙏
God bless you all Thank you again and for your Video Are you in Ottawa ?
It’s awesome to see the only two HVAC channels I watch collaborate and really helps to trust the information on either one