Replacing a Piston with a TXV Using the Danfoss TR6 Kit
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- Опубликовано: 30 ноя 2017
- Jesse and Bryan show their step-by-step process of replacing a piston with a TXV on a Carrier system using the Danfoss TR6 kit.
The system in the video contains R-410A refrigerant; Danfoss also has TXV kits for systems that use R-22 refrigerant. There are also three different kits for different tonnages; we use the small one for 1.5-3-ton systems.
The Carrier system's data plate indicates that a TXV should have been installed, but it has a piston instead. So, we start off the metering device replacement by getting a TXV for 3-ton systems. However, we have to make an external equalizer port and mount the bulb during the job, and the system did not start off with the means to start using a TXV.
When we take measurements on the unit, we get ~1,050 CFM, meaning that the system is delivering 350 CFM per ton and putting out just over 31,000 BTUs. We also determine that the evaporator temperature is 41 degrees (Fahrenheit) and that the condensing temperature is about 20 degrees over ambient, which is appropriate. The superheat is around 8 degrees and the subcooling is around 3 degrees.
Before we change anything out, we pump down the system to avoid contaminating it. The system has a scroll compressor, so we don't pump it down completely. We then recover the remaining refrigerant from the system.
We then remove the piston, which has a Teflon seal. In a heat pump, the piston can seat or unseat itself depending on the operating mode; these can become restricted or clogged, but they can't "fail." By comparison, TXVs can fail because they calculate superheat using refrigerant pressure in the bulb vs. the suction line. However, TXVs allow you to set the subcooling and control the capacity to a much greater extent than a piston, meaning that you can get more efficiency out of your system.
We decide to sweat in new copper and cut out the line-drier it is sometimes not a great idea to unsweat a line-drier because you can release all of the contaminants inside of it. Bryan and Jesse also create a groove for the external equalizer port (using the edge of a file and a scratch-all, not a drill).
The TR6 kit comes with the TXV, Aeroquip fittings, a flare assembly, and a chatleff fitting. We use the chatleff fitting. We sweat in the inlet and connect in the chatleff (making sure to protect the o-ring; that is what does the sealing). While brazing anything in, make sure the valve stays cool; it's good to use a wet towel or heat-blocking putty. We strap the sensing bulb to the side (though on top is generally acceptable as well) and insulate it.
Since we're working with a straight-cool system, we only need to sweat in a one-way filter-drier. Before we walk away from the job, we do a standing pressure test with nitrogen and bubble-test potential leak points. When we pull the vacuum, we remove the cores and pull the vacuum through the hoses directly, not the gauges. Our decay test shows an acceptable leak rate.
We use the data plate to set the charge; we try to aim for 12 degrees of subcooling. We use the recovered refrigerant to charge the system (bleeding our hoses first).
After taking our final measurements, we determine that everything looks good and that the capacity is better with the TXV instead of the piston (33,000 vs 31,000 BTUs). Since everything that we're looking for is in range, we don't need to adjust the TXV immediately after installation.
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Good one!! It's been a while to actually watch a video from home (using phone still no power 81 days after the hurricane...) but at least cell service is getting better... I've used a lot of danfoss products and there really good!! I use their txv a lot and it's great!! No adjustments needed!! Only in low temp refrigeration where superheat is low, but I haven't had to adjust on medium temp or a.c. applications!! Good products I'd recommend it!!
can i order this one i need to my mARINE aircon .. 0926634773
I loved the part where you filmed him walking with the torch. IDK why it's just hilarious to see other people doing normal routines too
Handtruck will be nice to carry torches😁
Why the hell am i only seing this now?!!! I love the video, very detailed, accurate and well filmed... thanks fellas
Great job,,,,I m 30 yrs in the trade u guys do Professional Job. Like ur boots, it tells a lot about the kind of work u do. I see the video was by the Book 😑tnks
Two tips to add. Put your caps off the unit on your gauge hose parks. Never lose or forget to put back on. Especially when two guys at the job.
Put a wet rag on the suction line to keep the aluminum/copper joint from overheating. You might be good with a torch. but still a good safety precaution. I never see any HVAC tech use wet rags
We use cool gel now
You buys act smart and sound sharp, make our industry proud!!! Keep up the vids and the pods, their Grrrreat!
Man you are a pro I didn’t see one cut on your hand after installing that sensing bulb and insulating it
The closer the TEV sensing bulb is to the evap suction header, the more likely your superheat will be a little high. I've had systems fail CA Title 24 charge verification with a weighed-in charge. Moving the bulb outside the coil case allowed the system to pass.
Excellent video, Bryan.
I like to see a/c vídeos I'm working on a/c too, but I I have to learn about the sub- cooling and super heat.
I'm spanish guy , I don't speak too much english, but I understand.
Congratulation your vídeo is very good!!!
You can do it!
Thanks guys! Great video!
Very nice and clean job
Very informative thank you!
Great job and video like always
Thanks for the good video. It plays a little fast, so I went 75% speed.
Some very good tip like cut the filter drier off vs heat it off, punched for the equalizer hole and use the file to score it a little. Good explanation of the equalizer, it's actually the pressure sensor. Some people mentioned capillary of the small tube, and that's wrong. It's just a pressure sending tube.
Showing final charging numbers are also good.
I wish to see how the filter driver was brazed in. Which are the good rod (45?), use flux or not (some sites say must use it for non-copper metal even with nitrogen) and how to avoid flux contamination.
They need to trim the bushes around that condenser coil. Airflow looks pretty restricted.
Nice video. Thank you for providing these videos. I have a question regarding charging a system after a repair, I was taught never reuse the refrigerant that you recover and especially from the yellow gray cylinder due to not being able to get a good vacuum on them. Is this true? Thank you.
Does this make the system work 50% better or 25% better? Make the compressor last 1 year longer?
Very NICE! Thanks.
Very good video! Can you list all the cool Testo gadgets you used for this install?
Great video
I have a curious question, was the only reason for not using a Carrier OEM TXV (that would have been quicker to install and less expensive) for the sole purpose to demonstrate the kit? Otherwise it was an informative video!
Danfoss makes it easy for the new guys..
2 questions here: 1st why didn't you just pull the Freon charge back into the condenser and leave it there during the job & 2nd if you drilled the hole for the equalizer fitting while you had nitrogen pressure on the lines wouldn't it blow out any debris that could contaminate the system. Newbie question !
NICE ,that music cracks me up
any txv issue, we replace the coil. Cheaper in the long run on labor.
Could you explain the scroll pump down ? I find a lot of young techs don't understand that. Even a few seasoned vets will pump them all the way into themselves. Great video!
Do you install the piston that comes with the condenser on the condenser liquid line?
Would you size the TXV based on the indoor AHU tonnage or outdoor unit? I guess they would both be the same tonnage right?
You have to pay careful attention to video, but I noticed he shut the outside unit refrigerant ports, highside first, then lowside, while unit was running then immediately shut down power to unit to capture the most refrigerant in condenser. I assume the compressor is okay with doing this as long as you shut power off quickly after closing ports. Any difference in method required between scroll or reciprocating reed valve compressor?
What its the pen tool you use to read the status of the machine? Thnx for the videos
Since TXV can adjust the refrigerant flow why they have to manufacture so many narrow ranged TXV? Just curious.
Do the Danfoss Universal kits work for heat pump applications if I remove the piston from existing evap unit? (no restrictions in reverse flow inside the txv ? will it work ? ) or I have to buy different type of txv kits ?
Very Good info here thanks !
rmwaseem yes they work on heat pumps, they have an internal check flow bypass
must be a danfoss commercial,whats the point in a "kit"
Sub cooling data on the condensing unit is a maximum degree . Carrier ever says to reduce it in certain cases. Here in the southwest we need all the condenser coil to reach a sub cooled condition on very hot days. reducing it by 3,4 degrees . Sub cooling ensures liquid at the TEV inlet, no flash gas entering the valve. To much reduces condensing area in the outdoor coil. And dosen't Increase NRE in the evaporator
Brian
Do you guys wrap you linesets with UV tape?...lineset take a beating from the weather....its mandatory in CA
Michael Madrigal yes, on All New installs
hello, how do you check for INDOOR superheat if there's no shrader port at evap outlet? Do you take reading at outdoor unit (suction) and measure indoor evap outlet temperature? then take the difference? thank you.
mark.r hvac yes that's the best you can do
nice vidio
is there a part or model number for the kit arrrangement or an online link to complete kit
I just found this, something that you didn't mention that would have helped to hammer the point home better would have been to show a fixed orifice superheat charging chart and explained how you charge under a certain set of conditions and then as conditions change bad things can happen, IE an unusually hot day, them setting the thermostat lower, dirty air filter or coils, Etc. causing you to flood the compressor.
Do you have the part numbers for the r410a and r22 kit
@ 5:28 why is the RH on the supply air so high? In cooling mode.. i thought system is lowering RH not increasing. I would expect the top row of readings ( return air 51.4 RH - supply air 87.8 RH ) to be opposite of what this is showing.
This video explains it ruclips.net/video/kn8KeumYfaM/видео.html
How's his phone stick to unit? What kind of case magnet?
any ideas on how to size a piston for a unit? I had to change my condenser to a 3ton Bryant due to emergency cooling needed. I have a 2.5ton Trane AHU and its not cooling correctly now. Any help will be appreciated. This is my wifes' acct. LOL
Depends on the condenser manufacturer. The manufacturer (supply house) has charts. Tell them the size and they will tell you what you need.
i just use a drill with about 20psi of pressure before i cut shit out. prep and planning can save alot of time. during a whoopsie ill use a zip screw and maybe just keep pressure if i have to drill it larger
Hello sir why you purge the air from blue hose ?
I think Jesse was upset you wouldn't adjust it a little open. I mean this video is all about overkill and I bet you could have a gotten a few more btu out of it!
Joe Shearer yes... true... you would know! You are the king of overkill 😉
You forgot to trim the bushes around the condenser looks horrible.
What is the name of the phone case
that is too much work, in real world i dont think customer will put out the money to replace piston for txv.
in 2019 few days from 2020 , i am still running a piston in mine in north fl ,,, cools fine electric bill is low its a heat pump 10 seer 4 ton ,,,,i am old and retired trying to make it last ,,,so far so good ,,,,nice vids young fellows ,,,,,all those fancy gauges WE did not have LOL ,,,,,,,thanks
How long did the job take?
About 40 mins
Danfos expansion valve service not good
“guys”
OMG. Why would you go through all that trouble and risk future issues when you might have had a mechanical OEM conversion kit or even a new evaporator to put in instead? Your videos are great but this kinda thing is asking for trouble lol.
Do you have Instagram???
No offense, but that was not needed.. No need in recovering to a tank when you can suck it out of the line set and pump it directly into the condenser via the true suction port. Just bleed ya lines good. No biggie. No need it putting it in the tank.. Pull it directly from the lines in on the recovery unit and out the true suction port on the unit.
Sorry what
Screw that crap use a piston
System was working great with tbe 20 degree temp drop. What are you wanting?. The money the custom spent on that repair they will never recover. The only person benefiting from tbis repair is your company. I dont it
First, you might want to proof read your comments. I can hardly understand you. Second, this was done for free as a demonstration. Third, temp split is not the only indication of operation. A TXV maintains coil feeding over a wider range of conditions.
Without airflow measurements, you don't know if the unit is performing well regardless of the temp drop. You can have problems covering up for eachother.