Long Line Applications
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- Опубліковано 11 сер 2021
- In this class, Bryan teaches the Kalos techs about long line applications, accessories, and allowable line lengths. Many techs don’t fully understand the challenges of long lines. So, Bryan covers a wide range of issues and practices with long lines.
You can find the long-line piping guide we’ve used at carriercca.com/pdf/products_p....
Long lines can cause refrigerant migration. Long lines simply move more refrigerant, making migration much more likely. On top of that, a pressure drop is possible throughout longer suction lines. When you have a lot of refrigerant inside the suction line when a unit is off, it will often migrate to the condensing unit. (In a few specific cases, liquid refrigerant may migrate to the evaporator. Your unit is at risk of a flooded start when that occurs.) We also shouldn’t bury suction lines for long distances to reduce the risk of a flooded start. The ground is typically colder than the air, so the refrigerant is more likely to condense in the suction line if it is underground in a cold place.
When the system is off, you ideally want liquid refrigerant to be in the liquid line or condenser coil. Anywhere from the discharge line to the metering device is in the “safe” zone for liquid refrigerant. So, when adding liquid refrigerant to a system, you will want to add it to the liquid line so that it can vaporize in the evaporator before making it to the compressor. We NEVER want liquid in the compressor, and we only want vapor to be in the compressor while the system is running.
Straight-cool long-line A/C systems require TXVs if the line’s total length is over 50 feet. If the outside unit is above or below the indoor unit, that system will require a TXV if the line length exceeds 20 feet. TXVs are required in long-line applications because they have hard shutoff (HSO) or non-bleed valves that help prevent refrigerant migration.
A long-line A/C system may also require long-line accessories. These requirements depend on the liquid line diameter, the presence of a TXV, and where the outdoor unit is located in relation to the indoor unit (above, below, or level). The range for minimum lengths can be between 35-175 feet, depending on each of those factors. (Most of the time, we use ⅜” liquid lines with a TXV, so the minimum is usually 80 feet.)
Heat pumps with a ⅜” liquid line diameter and TXV will need long-line accessories if the lines exceed 80 feet in length (or if the vertical difference between the indoor and outdoor units exceeds 20 feet).
Pipe fittings add equivalent length, so be sure to take those into account when you measure line lengths to determine if you need long-line accessories or not.
Your allowable line lengths will be significantly greater when your condenser is above your air handler. When your condensing unit is higher, the refrigerant going to the air handler will maintain pressure more easily as it moves downhill towards the metering device. The static regain keeps the pressure drop from getting too strong.
In the case of our Carrier heat pump, we have level indoor and outdoor units situated 100 feet apart. We have a ⅜” liquid line with a TXV, so we will need a long line because the distance between the indoor and outdoor unit will exceed 80 feet in length. As a heat pump, the unit will need a standard accumulator. Based on our accessories guide, we need a compressor start assist capacitor and relay (hard start kit), crankcase heater, and hard shutoff TXV. However, we also need a liquid line solenoid valve (LLSV). These LLSVs are NOT for pump-down applications; this LLSV shuts down the liquid line when the system shuts off.
The hard start kit helps start up the compressor. The capacitance needs to be properly matched to avoid putting too much current on the start winding, so it’s a good idea to use the manufacturer’s hard start kit, not a universal one.
When it comes to installation, we start off by installing the bellyband crankcase heater. The schematics can tell you how the crankcase heater attaches to the wiring. Remember, we only want the crankcase heater to energize when the unit is OFF. When we power up the condenser ONLY, we no longer read voltage to the crankcase heater. When we shut the unit off again, our meter begins to read voltage again.
The next step is to install the hard start kit. We can test it by measuring our start amps with it in and without it in.
We install the liquid line solenoid on the liquid line. It is a normally closed valve that opens when energized. It should be installed two feet from the condenser, and the arrow on the valve must point towards the outdoor unit.
We also discuss:
Pump-down or pump-off systems
Potential relays
Capacitor windings and startup amperage
Wiring diagrams
Check out information on the 2022 HVACR Training Symposium at hvacrschool.com/symposium/.
Read all the tech tips, take the quizzes, and find our handy calculators at www.hvacrschool.com/.
Thanks Brian!!! I’ve learned a lot by watching your videos
I'm glad your taking your time to teach the guys coming up in the trade. I never got that. One time I asked an owner about training. His respones was who needs training, don't you know what your doing. I asked another owner and his response was we don;t have time for training. That company had a 75 percent call back rate. Great for making overtime.
I have trained TONS of HVAC owners in the Charlotte area. It is a VERY difficult job, hats off to this guy!
@@SuperVstech Trained owners to do what.?. I leaving the HVAC business. Just not worth it any more. Too much BS . I can take a 15 dollar minimum wage job not have nearly as much stress .
@@johnd4348 you would be surprised at the amount of owners who don't actually know theory or design principles, let alone how to operate a business. For the record, I agree with you: starting up a small business right now would be an incredible amount of stress.
@@johnd4348 I train techs, they go on to own their own company. I train service, install, bidding, sizing, and customer conversation.
Excellent class! I like how the instructor engages with the students and asks why. It forces them to think and formulate an answer in their head, whether or not it is correct. This feed back is important to the instructor as to how well the students are absorbing the material. Also consider that people are much more likely to remember mistakes in thought or action and therefore correct their actions in the future.
This is fantastic informatio! Now I know why I was replacing all those after markets hard starts on the Trane recips with OEM and they were working! Thank you
Good teachers can make you interested in anything!
Your videos are great and very informative. I use them to prepare to train our new service techs. Really appreciated the Power In The Blood hymn reference. "Wonder working pow'r"
Please negative comments need not apply lol. Thank you for another great video with an awesome instructor :)
Like the class 👍. Great explanation. Thanks for your awesome classes!
thank you so much "great class"
You really got me out of a very complex situation that I had, thanks again
love this class thank you
Very nice video. Really enjoyed and learned alot.
Thanks for sharing
Great class. Thank you! But when are we going to learn about burying the linesets? 😄 Thats an interesting topic I am in Canada and everybody says that it is not allowed. What I read in manufacturers bulletins, they are also against it, but I see that in Florida everybody is burying them 😄 it would be great to hear your experience of burying them and how to prevent flooding.
Yes very interested in this too.
Great video!
I am learning so much. 🙏 Thanks
thanks Brain ,lots of good information
Tremendous class I loved it
Brillant distilazion down to how anbd why. for a bunch of complex topics. Thank yoiu., raphael nyc
Thanks for discussing problem and doing training. It is going to change again with new A2L's coming next year. (Long lines may disapear)
Great videos 😜
I was told by D&L to remove the relay & direct wire a hard start straight on a fairly new 2 ton Goodman heatpump.. that a previous tech had started removing parts & he thought the factory hard start was a special run capacitor... it sat for 8 months.. I figured out the entire reason it wouldn't run was because it had 0 refrigerant in the system. He'd melted both Schrader valves & it leaked out.. 😅
I like how energy kalo hes free in spirit like how he can joke with his classmates when I'm teaching I'm tend to sometimes do things wrong but not Ina manner that I can go back from like for instances for getting to put the flex seal on the cooper line before soldering so that the tech can only see what I gave to go through cutting ✂️ open to only make it look like I never cut it so he sees that it's ok forget but so he won't have too if I make sense !!!.
That was interesting, entertaining, informative and fun. Now a question that may seem odd to a proper tech. What keeps the liquid out of the compressor during a power-on reversal like entering defrost mode? Probably stupid obvious to most but I don't know.
What can we do to prevent having problems with a buried pipe?
yes please
Brian,
Not a tech but Im trying to learn more about capacitors and you answered a lot, but i still have questions. In short, put a universal condenser fan motor and matched dual capacitor on a trane with running but too noisy, fan motor, it started and ran but it seemed to be not up to full speed and had a pulse feeling vibration. Ended up calling a local tech and he installed an additional run capacitor (small one) and it ran great . What should i have measured or looked for to have known this. This unit at daughter's house in Ga. And Im back in Tx now.
Thanks and these vidios are very informative, great job
dude, you're a God! Hella funny, too.
Ya missed a test. The crank case heater not only heats via the band, it also pulls watts through the compressor windings, and the motor windings ALSO produce a small amount of heat. Ya can measure the milliamperes on the common winding.
Finally some quality entertainment
Brian, thanks for the information. You mentioned that you would offer advice on how to bury line set, if necessary. I understand the potential for condensation but in my case there is no option but to bury for approximately 35 ft. The install in in North Florida (Jacksonville area). Advice please on how to do this while minimize condensation
I never clicked so fast on a UA-cam video :D
After he said "if you have a 1/4" line and a txv.." I was instantly ready for "You might be a redneck"
I thought this was about fishing. We use to long line in the Ocean.
install a solenoid in a "buried line situation" and ur fine
nice vid, liquid is a compressors enemy, just the same as overtemp.
So what if we don’t have a sight glass for long line as a visual will sub cooling be still accurate for a 120+ feet of line to go by ?
short answer: no
hey great information. the literature you read from where can i get from?
Your guy asked why wire the solenoid on the y call, not on the O call. I hope you answer him… most thermostats energize the O terminal when in heat mode, the entire season, the valve would remain open.
So why can we do that when we have a 5/16" line over a 1/4"?
Finger over a straw principal been actually locked out liquid in liquid line in a substantial enough amount to adequately feed the TXV and have totally superheated gas
By the timer on the way back from the evaporator to the condensing compressor
Is there more room in your class ?
Omg a shovel? 😀
Where's Aaron?
Sometimes you get a class that you need to help you along in your career,I know your investing in your business!!!
🥃🥃🍺🍺🍺🍿👍🏻
Stay safe.
Retired (werk'n) keyboard super tech. Wear your safety glasses.
What is the weakness of piston of metering device?
None, they work but not "efficient "
High seer unit with low ambient = ice up's. Txv's has a wide range of operations to compensate for external factors.
@@airmech5083 high seer unit wouldn't have a piston.(shouldn't)
@@realestateservicessaleshea99 if the txv is a separate purchase, most guys go with the factory supplied metering device (piston).
A piston metering device has no variability.
But we must charge in liquid 😶
Current is real lazy it always find the shortest path to its source.
Power power wonder working Power 😂
as far as 1/4" lines, u use larger to reuse line sets with higher efficiency in the future... line sets are the largest fee wen replacement is needed... change outs are easy. same applies to your low voltage rough imo.
simple way to look at it: what do u need to do to replace a 10 seer with a 16 seer, 2 stage or better?
a change out is cheap if they have 7/8 3/8 and 8wire low voltage, no?
now, consider what most builders have roughed... lol
AC nerds101 lol 😎🤣😍👍🥶🔥😱👌
Fuck no subtitles...
I skipped your video yesterday. The thumbnail was not good.
Oh no... sorry I failed you. Please forgive me.
@@HVACS Brian, thanks for sharing your training vids, great topics that get us thinking deeper about the whys and hows of things!
@@HVACS we are not going to communicate in that way. Lets address each other with out the sarcasm please. Is that ok with you? ( referring to you mindset video)
@@jamesmitchell2224 well played sir
Oops. My bad. The comment about the thumbnail was meant for another channel.
Было бы неплохо если были русские субтитры
Teachers who constantly (ask the class why?) (who can tell me ? ) is such a bad method and flow. It causes students to mind wander and decreases participation. Only the me,me,me guy will always answer. Just teach the goods.
That's an opinion you are entitled to
Beamcannon I would fall asleep in your class. Pretty good lecture overall. Pizza guy always baffles me a little.
SO TRUE, Just look at the guys
Encouraging discussion and allowing for active thinking in the class is much more effective than lecturing. I am an HVAC trainer and this is exactly how I conduct my classes. Notice that Brian occasionally pointed his questions at students that hadn't answered yet to encourage the whole class to participate.
When it's an impromptu class like this without preparation on the part of the students, it's necessary to actively involve them in the learning process.
@@Oldthesis the camera shot of the group here does not support your theory. However it does work for some like I said.
Great videos 😜