How to Replace a Piston with a TXV Metering Device! HVAC Service & Install Training!

[@deanmartin1966]

I just replaced a txv with a piston also. Was for a child daycare. They couldn’t afford a new txv. Works great. Good video Craig.

[@moy6569]

Your charging and service procedures book just arrived from Amazon... thank you for this, well put together. Your awesome.

[@acservicetechchannel]

Thanks for watching, I hope you enjoy it!

[@paulschuebel5487]

Here because HVAC TV recommended the channel. Good things so far

[@ZZZRSC]

Thanks!

[@borshardsd]

Thank you for the hard work and great info. Any reason you did not recommend pumping the refrigerant into the coil? Micro channel? Scroll compressor?

[@ali.7708]

I offer you respect and gratitude for the information you provide on this useful channel, and I thank you very, very much with deep appreciation for you and your information.❤❤❤❤❤❤❤

[@acservicetechchannel]

You are very welcome!

[@bobward7489]

Why recover when you can pump the refridgerant into the condensing unit? Simpler, faster and cheaper.

[@pineychristian]

Yes if it all fits. It's nice when linesets are short but, when they are very long doubt that's going to happen

[@dxboy1513]

doesnt work too well if its a scroll compressor

[@rcstl8815]

It's easier to trash a scroll doing pumpdowns. I am not sure of current recommendations but manufacturers used to discourage it.

[@pineychristian]

I've never had any issues with scrolls pumping down or failing from pumpdowns. I'm strictly a commercial tech now and all my Mcquay, Daikin MPS , AAON's and destrons all pump down on their own to shut down when a call for cooling is satisfied. This is completely normal operation for these units. This is to prevent liquid refrigerant from migration and flood back to the compressors which is way worst for any compressor. They pump gas not liquid.

[@Timboslicce]

Basically pump it down to about 1 psi with a scroll type to prevent slugging. If you’re in a pinch

[@ZZZRSC]

Thanks for the professional video and instructions

[@derrickenbuenosaires]

Another tip for making new connections on the line set is pressurizing the component that needs an access to say about 50 psig of nitrogen and just drill while it's in a positive. All that crap will come flying out so wear goggles.

[@buzzlightyear7419]

Question: Why are the sensing bulbs cylindrical? Given pipes are also cylindrical at best the intersection between pipe and bulb is a line which in a purely mathematical sense has zero area for thermal conduction. In a physical sense that makes the time it takes the sense bulb temperature equalize with the pipe temperature very long relative to the on-off cycles of the air conditioner. Thermal grease or an indentation on the bulb side matching the pipe curvature would massively improve thermal conductivity and allow the TXV to react to changes faster. Obviously its easier to manufacture a cylindrical bulb but better conductivity would allow the TXV operate the coil more efficiently and protect compressor better.. Also, thanks Craig, I love you book and learn so much from these excellent videos of yours.

[@LRBennettInc]

Great video you never mentioned to remove or make sure the shrader core is removed from the equalizer if there is one Tranes RunTru airhandler. Let me know if I'm wrong? If it has a black plastic cap it has a core.

[@paulrozinski1488]

Do you see a trend change to EXV’s instead of TXV’s. The biggest annoyance I see with TXV’s is when the bulb loses its charge. Opinions, please 👍👍 As usual, a very informative video. Thanks again .

[@pineychristian]

Probably because that seems the way the industry is going. My biggest thing with TXV's is installers not brazing with nitrogen purge. Then the oxidation later down road plugs the TXV and service has to go fix it.

[@petef.4361]

I want to power my house with a generator during power outages, including my 3.5 ton A/C. I hear it is recommended to install a "soft-start", so that the generator has an easier time starting the A/C. Can an electrician install the soft start, or should the HVAC company install it if I don't feel comfortable doing it myself? Does installing a soft-start do anything bad to the compressor, like shorten the lifespan, or is it actually beneficial to have a soft-start?

[@rcstl8815]

I have never replaced a failed piston. I lost count of the failed TXVs that I have had to replace. Piston is more dependable and savings from TXV or almost undetectable. 2014 and 2015 nightmares come to mind.

[@nick99995]

What I would like to know is, lets say you have to replace the evaporator (because too many leaks). Should you add oil to compensate for the amount still left in the old evaporator? This is a question that no tech ever talks about. Recovering a charge to replace a component... what to do about lost oil? Thanks for making these videos!

[@rcstl8815]

Twenty years on and I haven't had a compressor fail for lack of oil. Oil pools in the CU and only a small amount is in the evap. Running on a low to no charge so the refrigerant isn't cooling the compressor motor is the usual death.

[@wittydisplayname1761]

Non-AC guy here. Could you shut the liquid line off first and use the compressor to pull most of the refrigerant into the outside unit then shut off the vapor line?

[@jrrosales7918]

Excellent thank you for explaining

[@acservicetechchannel]

You are welcome! Thanks for watching!!

[@harmonairllc2368]

Do you leave the 1/4 inch schrader in the equalizer line or remove it ?

[@acservicetechchannel]

That would need to be removed because the tube connector does not have a valve core depressor, thanks!

[@rvamtbram]

Any thoughts about retrofitting a txv on an outdoor heat pump that’s using a piston?

[@rcstl8815]

I would say "stop the thought!"

[@zekenzy6486]

Great video. Thank you for sharing. Have a nice weekend

[@acservicetechchannel]

Thank you for watching!

[@geraldolambski412]

Will this help with a mismatched coil & air handler/furnace ? 18 yr old furnace has lower than needed air flow & will be replaced when it fails but need a solution now!

[@throttlebottle5906]

low air flow, is low air flow, increasing airflow is the only real fix. while switching to an txv will certainly help now and later(efficiency increase regardless of ambient temps) and better control of coil temperature, reduced floodback to condenser, etc. again AIRFLOW = number one fix

[@rcstl8815]

How mismatched? Most furnaces have three or four speeds so if the CU is small, slow the air down. If too big, set it as slow as possible. A TXV is not a magic wand.

[@Mo4Honesty]

How do you recover from the coil/ lineset only if there is no access port on the indoor coil? Are the service valves located inside or outside the shutoff valves to the condenser?

[@rcstl8815]

The access ports are on the lineset/evap side.

[@victorvelarde310]

great video

[@tube8533]

great

[@danielkelley7422]

How much of an efficiency increase do you get with a TXV versus a piston?

[@HVACMAVERICK]

@@danielkelley7422 The difference is staggering enough to never use a piston again.

[@danielkelley7422]

@@HVACMAVERICK so can you provide a percentage?

[@throttlebottle5906]

@@danielkelley7422 there is no exact percentage, because the piston efficiency varies greatly with indoor and outdoor ambient temperatures(+humidity) and proper airflow both indoor and outdoor over the evaportaor and condenser coils, at certain points in both ambient temperatures(+humidity) the piston will be about equal in efficiency, but that's a narrow window of perfect conditions. in the real world, efficiency gains could be 0 to 50% or greater in very extreme situations. even this figure is a guess, becasue again it varies all over the place.

[@danielkelley7422]

@@throttlebottle5906 Here’s the problem. A piston can’t fail. A TXV can fail and likely will fail. So when it does fail, the customer is looking at a repair bill of what, $1,000? So any potential savings are gone.

[@throttlebottle5906]

@@danielkelley7422 yes, that can happen and does, especially if they didn't keep everything clean, flow nitrogen while brazing or reusing linesets/parts without cleaning very well. but, a piston metering device ran in low ambient conditions indoor, outdoor, both or with wrong charge amount, causes severe liquid floodback to compressor, which washes oil out and liquid slugs it, HVAC/R compressors are not meant to pump liquids, only gasses/vapor. all the oil being out in the system vs. lubricating it is certain death. with later refrigerants (R410a/newer) the charge is more critical to keep from killing the compressor with liquid, so TXV/EXV is pretty much required now. yeah, they're no longer as durable as they once were, whole refrigeration/hvac systems used to last 30+ years with ease, of course that's when taken care of and not ran in extreme conditions.

[@cruzfernandez4554]

Correct me if I am wrong; I did the same thing, but I always vacuum the system at the end.

[@MoonRambo702]

He mentioned that quickly

[@DaríoMartínez-w6w]

How much would be my target subcooling if I retrofit a txv just like you did? Thaks a lot.

[@eric01406]

8-10 degrees.

[@acservicetechchannel]

The target subcooling for a single speed system shoukd be posted on the outdoor unit rating plate. if not, we usually set to 11 degrees, thanks!

[@HVACMAVERICK]

@@DaríoMartínez-w6w And make sure your condenser coil is clean before charging.

[@rcstl8815]

@@acservicetechchannel And/ or, the installation directions make "suggestions."

[@KentuckyReef]

Do a video on why not one compressor manufacture supports the use of Nylog!

[@harryschrysan3183]

It's to cover their ass. They don't want any foreign material of ANY kind into their system. Warranty is gone if you use nylog. I call bs in my opinion but what do I know. They are the engineers 😂😅

[@harryschrysan3183]

I still use it tho idgaf!

[@KentuckyReef]

@@harryschrysan3183 I use it as well. I just wonder why compressor manufacturers don’t want us to use it

[@harryschrysan3183]

As I mentioned they consider it a foreign substance and they wouldn't approve warranty if something fails. If you tell them you used it they will cancel you 😂.

[@KentuckyReef]

@@harryschrysan3183 👍

[@houstonsmitherman6888]

Did this today

[@willb.9225]

So I'm looking to change the piston to allow r22 to 410a refrigerant change is this the same thing or similar

[@rcstl8815]

Yes. We commonly do this when the customer "can't" afford a full system replacement. Or 410 evap on older R22 system.

[@kangaroogod]

Probability of failure just went up by 1000%… I get it,, more efficient, better capacity but the number of txv failures is crazy

[@MrHVACguy71]

I just replaced a TXV with a piston

[@francom6230]

Simple seems better to me, but I am not knowledgeable in this subject..

[@MrHVACguy71]

@@francom6230 homeowner was happy that her a/c was working better than it had been the last several years after having several techs tell her it was doing all it could and of course trying to sell her an entire new system since hers was 15 years old

[@fkdeazevedo]

Simple is better. Txv cause issues years down the road

[@cdubs1723]

Pistons don’t fail

[@HVACMAVERICK]

@@MrHVACguy71 Yes, txv’s fail… sometimes. But pistons are very inefficient all the time.

[@larryrichardson5167]

If you did this on a system that was installed with a piston, how could you calculate the target subcooling ? I know how to calculate target SH, but , what about SC ?

[@shifter8207]

Charge subcooling to around 6-10 degrees I’d say that would get you close.

[@acservicetechchannel]

The target subcooling for a single speed system shoukd be posted on the outdoor unit rating plate. if not, we usually set to 11 degrees, thanks!

[@rcstl8815]

Recommendation is 10 degrees +/- 3 unless marked on the CU. Same variance on SH.

[@evane8423]

How far in should the equalizer tub go into the line?

[@HVACMAVERICK]

@@evane8423 Doesn’t need much. Just far enough that the braze doesn’t overcome the end of the tube.

[@evane8423]

@@HVACMAVERICK thanks for the input. I wonder if there could be a general rule of thumb that's somewhat consistent regardless of the size of the equalizer tube. Maybe for example, insert the equalizer line until it hits the bottom, make a mark, and then pull it back out to even the end with the exterior wall of the tube. Then... Roughly divide the difference for halfway and mark, then braze. Or 1/4"...or 1/8"..ect. Is there a manufacturer spec for penetration regarding this retrofit or simply case by case and experience know how?

[@HVACMAVERICK]

@@evane8423 Try not to make it more difficult than it needs to be. The TXV manufacturers have already done the math for us… The purpose of the equalizer tube is to "read" pressure. Regardless of the insertion depth, it will still read the same amount of pressure… As long as the tube opening isn’t restricted completely by the braze media.

[@evane8423]

@@HVACMAVERICK would it be reasonable to compare the purpose and function of the equalizer tube, to a scuba diver that must add physical weights for a net zero buoyancy in the water?

[@evane8423]

@@HVACMAVERICK what is the flow rate of refrigerant on the suction line? From your last answer, angle is not a concern nor depth penetration. I suppose my original question was the concern for the added turbulence giving a false pressure.

[@markniles3013]

Just leave the piston in and keep life simple and cheap.

[@РоманСеменов-г3б]

Гаечные ключи должны всегда двигаться навстречу друг другу.

[@throttlebottle5906]

where's your torque wrenches for proper torque values... yeah I couldn't resist poking about it. lol youtube police. good training videos

[@jelonniejones4863]

He recovered because you can’t pump down a condensing unit that has a scroll compressor or thin micro channel fins

[@HVACMAVERICK]

You can use the pump down method with scroll compressors, I do it often. You just can’t with a micro channel condenser coil because they typically don’t have enough capacity for all the refrigerant.

[@jelonniejones4863]

@@HVACMAVERICK thank you for letting me know this information appreciate it 👍

[@napoguevara6450]

👍👍👍👍❤️

[@BMC867]

Why would you ever want a TXV instead of a piston I don't understand.

[@emmaa427]

To make it more efficient and responsive to the cooling load demand

[@BMC867]

@@emmaa427 Maybe by a small margin, sacrificing reliability and stability.

[@shifter8207]

Why couldn’t you pump the system down and not even bother recovering

[@harryschrysan3183]

Yeah, you could do that unless it's a micro coil.

[@MF-tm4qu]

I ordered that book paid for it never got it let you know over and over and you ignored me. Took my money real quick but never got back to me. So be careful when you order this book they ripped me off. Your good at what you do but not honest cause I never got my book I paid for.

[@acservicetechchannel]

What platform did you order it on? Did you order from acservicetech.com ? If so, please email us at [e-mail] with your name, order number, and date you ordered and we will take care of it. Not sure where you tried to contact or where you ordered that from?

[@HvacKat]

I got mine from Amazon right away and now am saving up for the mini split work book!! He must be a troll.

[@andrewveres3965]

Hey don’t know if you are from California but have you ever seen a ultra low nox furnace they are the biggest pieces of crap on the market today

[@vicg1973vg]

Do you leave the steam valve were you connect the line

[@walterdennis7023]

Why don't you just pump the whole system down into the condenser.why recover?

[@acservicetechchannel]

You dont want to pump down a scroll compressor to the point where no refrigerant is left in the compressor shell which is the low pressure intake because the electrical terminal or winding can short to ground, which will cause the compressor to fail.

[@Bill_CBR]

@@acservicetechchannel It's the little things that get ya. 🙂

[@andrewveres3965]

I pump down scrolls to at least 20 psi then recover the rest it’s always worked for me

[@timrob0420]

@@acservicetechchannelwhat about rotary compressors?

[@ZZZRSC]

@@acservicetechchannel I believe there might be other reasons, but I do not understand how it could cause the terminal to short to ground.

[@luismontoya5189]

He recovery the refrigerant,cuz he can make more money for that.......they are trained for that...$$$$$$$..........uff

[@MoonRambo702]

You can put the same refrigerant back in.. how does that equal more money?