A/C Pros! How do you bend tubing? Please help!

[mpire]

I am trying to run the tubing for the Garage A/C unit, and I have already messed it up.

This 3/8ths inch tubing seems much stiffer than I remember.

I need to make 3 or 4 right angle turns for this install.

Here you can see its started to crimp.

And closer up here:

I haven't forced it, but its just not liking me. There has to be a better way to do this. Any recommendations would be welcome.

I am stuck at this point, so I am just going to stuff the hole and call it a day until I figure this part out.

Also, would you cut off the tube and start the bend over?

 

[luvit]

tube bender $10 at Lowes.
I had to do the same thing you're doing, tube bender is the safe solution.

 

[mpire]

Looks like I am headed back to lowes.

So is the tubing salvageable with those dents in it?

 

[airbuff101]

Can't be done!
There is no such thing as a Tubing Bender. I checked.
Someone should invent one.


airbuff

 

[mpire]

Funny, there seems to be as many solutions on the internet as there are keys on a keyboard.

The question is which one should I use?

 

[luvit]

Looks like I am headed back to lowes.
So is the tubing salvageable with those dents in it?

from my perspective on the pics -- you should be fine.
my own ignorance would suggest that the dents do not appear to cramp no more than 1/3 of the opening.
your crimps will never be 100% gone, but the tube bender may give them a better appearance.

 

[mpire]

I don't care how they look.

I am concerned about function.

 

[luvit]

I don't care how they look.
I am concerned about function.

you're good to go, watch those areas as you use the tube bender. i doubt they will kink further.

 

[fabrk8r]

Use a tubing bender like the one pictured by luvit. Practice first.

As already mentioned, don't try a bend where the kinks are. Fix the kinks by using a flaring block. Slowly and carefully tighten the block over the kinks.

Another option, if you know how to do proper refrigeration flares, is to cut the flare-nut off the end and use a spring bender to make your bends then re-flare (don't forget the nut).

 

[luvit]

As already mentioned, don't try a bend where the kinks are. Fix the kinks by using a flaring block. Slowly and carefully tighten the block over the kinks.

ah.. i forgot about this trick on my own project to fix my slight kink.

 

[metaldad]

do not try to manipulate where the kink is. with the thin metal these days, it'll crimp.
you can attempt to re round the kinks with a flaring block. or cut it out and sweat in a coupling. tubing bender.......... the one previously displayed is an inexpensive, tight radius bender. the type depicted usually can accept 3 sizes, 1/4, 5/16, 3/8 od tube.
there seems to be tool collectors here. j/b makes the elite benders, 1 tool per size.

flaring block. the one previously shown is a generic type. difficult for a novice to make a proper flare. Ridgid makes the creme dela creme block, it has a clutch.

do not use any sealant on a flare joint. just a lubricant is necessary

 

[T mac]

use a tubing bender and if you have to cut and coupler the lines make sure you braze the lines do not sweat them with soft soldier all your connections should be brazed.

 

[fabrk8r]

do not use any sealant on a flare joint. just a lubricant is necessary

Refrigeration oil.

 

[fabrk8r]

use a tubing bender and if you have to cut and coupler the lines make sure you braze the lines do not sweat them with soft soldier all your connections should be brazed.

If you do any brazing on the lines make sure you purge with inert gas (nitrogen) to keep oxidation to a minimum. This should be done on any A/C system, but is particularly important on these mini-splits.

 

[danski0224]

So is the tubing salvageable with those dents in it?

The tubing may be OK, but do not attempt further bends there.

An adjustable wrench set to the OD of the tubing where it isn't dented can usually straighten minor problems.

The question is which one should I use?

This one: http://www.drillspot.com/products/70337/Imperial_Eastman_364-FHB-06_Tubing_Bender

You may also want to re-evaluate the need for 90* bends.

A spring bender will also work if the radius isn't too tight and before you flare the ends (uh, remove the spring bender before flaring).

Definitely practice.

 

[T mac]

good call on the nitrogen i forget to add that in and i dont see getting away with out any brazing unless both in and outdoor units are flare fittings if thats the case i might consider getting some leak lock for the threads just for some added assurance of no leaks.make sure you leak check it with nitrogen and then pull a vacuum before opening the valves.vacuum to at least 500 microns or better to assure the system is clean and dry.

 

[theoldwizard1]

Dumb, but related, question.

Can you use "standard" compression fittings on A/C lines ?

Is the tubing the same (thickness, strength) as copper tubing used for water and gas ?

 

[danski0224]

Can you use "standard" compression fittings on A/C lines?

Yes, you can use water compression style fittings, if you want refrigerant leaks.

 

[green.bubbly]

Mpire, where are you running that tubing? I am a little confused about your setup/system. On my mini-split, the lineset came out the back side of the unit. Yours looks like it comes out of the front side???

 

[mpire]

Yeah, this unit is different in that the tubes are in the front of the unit.

Its only 4 inches thick though, so its really not all that much of a difference.

After hookup, then you put the cover back on.

 

[green.bubbly]

Yeah, this unit is different in that the tubes are in the front of the unit.

Its only 4 inches thick though, so its really not all that much of a difference.

After hookup, then you put the cover back on.

That would have worked better in my shop since I ran my lineset in the wall. It was a pain trying to hang that unit and connect the lineset in the wall. Is this the same make/model unit as the one in you other thread?



I was watching a tv show and they filled the line with water and then froze it before they tried bending it. The frozen ice would allow the tubing to bend but not crimp. Of course this would not be practical for an AC unit. I forgot what they were using the tubing on.

 

[mpire]

Thats how they make trumpets.

 

[Falcon67]

Dumb, but related, question.

Can you use "standard" compression fittings on A/C lines ?

Is the tubing the same (thickness, strength) as copper tubing used for water and gas ?

High side pressures can run 250 PSI and up. I would not try a regular compression fitting with that kind of working pressure. Refer tube is also not the same as water copper. Not sure the difference, but it's there.

 

[MoonRise]

Use a tube bender, either the coiled-springy type for large(r) bends, or the nutcracker-type for tighter radius bends.

http://www.ehow.com/how_7616734_bend-pipe-kinks-air-conditioner.html

http://www.copper.org/applications/plumbing/techref/cth/cth_4bend_gencon.html


As to the use of that kinked tubing, I would say No-Go. Performance-wise, probably no problem. Durability-wise and/or leak-wise, iffy in my book. Kinks in ACR (HVAC lines) mean that section is NG and must be replaced.

Tight right angles? Put in right-angle fittings. And HVAC fittings are NOT soldered on. They are brazed, usually with something like Sil-Fos.

http://www.silfos.com/htmdocs/product_support/faq.html

http://www.silfos.com/htmdocs/product_support/alloy_selection_guide.html

Unless you are an HVAC tech (in which case you would already know all these answers), how are you going to get the line set purged, evacuated, and then filled with refrigerant and (the appropriate) oil? Cause I don't think if you call in an HVAC tech to do the evac-purge-fill that they will be in any way happy to work on a system where the lines are kinked already.

 

[fabrk8r]

how are you going to get the line set purged, evacuated, and then filled with refrigerant and (the appropriate) oil? Cause I don't think if you call in an HVAC tech to do the evac-purge-fill that they will be in any way happy to work on a system where the lines are kinked already.

If this is a new mini-split the unit is pre-charged with the proper amount of refrigerant and refrigeration oil in the condenser section. After the connections are made, evacuated and leak checked the service valves are opened to release the charge into the evaporator section.

As has already been mentioned, this unit needs to be properly evacuated to a micron level of at least 500 microns to ensure no leaks and that all moisture and non-condensibles have been removed from the system.

 

[mpire]

Unless you are an HVAC tech (in which case you would already know all these answers), how are you going to get the line set purged, evacuated, and then filled with refrigerant and (the appropriate) oil? Cause I don't think if you call in an HVAC tech to do the evac-purge-fill that they will be in any way happy to work on a system where the lines are kinked already.

If you don't have a professional HVAC "install" the system, you don't get a warranty. I plan on doing everything short of connected the copper fittings. Then Sean can come and do everything in about 45 minutes.

I don't get over charged, and I get a professional quality install, assuming I don't completely screw up the lines with crimps etc. And Sean gets a pretty easy buck and tells me if it looks good to him or not, and lets be honest, we are paying for his professional experience, not his grunt work.

The key is not to waste any of his time doing stupid stuff that a complete A/C ***** could be doing like running power wire, hanging the unit on the wall, etc. That will cost me $100 an hour for him to do, but its pretty much free for me to do.

 

[luvit]

..and lets be honest, we are paying for his professional experience, not his grunt work.

The key is not to waste any of his time doing stupid stuff that a complete A/C ***** could be doing like running power wire, hanging the unit on the wall, etc. That will cost me $100 an hour for him to do, but its pretty much free for me to do.

i do a lot of things like this.. i may be doing some grunt work for a central air unit if i close on another house this month.
.

 

[MoonRise]

If you don't have a professional HVAC "install" the system, you don't get a warranty. I plan on doing everything short of connected the copper fittings. Then Sean can come and do everything in about 45 minutes.

I don't get over charged, and I get a professional quality install, assuming I don't completely screw up the lines with crimps etc. And Sean gets a pretty easy buck and tells me if it looks good to him or not, and lets be honest, we are paying for his professional experience, not his grunt work.

The key is not to waste any of his time doing stupid stuff that a complete A/C ***** could be doing like running power wire, hanging the unit on the wall, etc. That will cost me $100 an hour for him to do, but its pretty much free for me to do.

Hey, I'm all for DIY.

But you should try to do the job as good (or better) than the 'pro'. IMNSHO.

Kinks (or 'crimps') in the line = NG

Cut out (neatly!) the damaged section there and try again.

And I think the pump-down time and time for the lines to spend under vacuum is going to be close to (or should be) at least your proposed (estimated?) 45 minutes for your HVAC guy (Sean?) to do the 'whole' job. Add in prepping and then brazing the lines and fittings (a couple minutes here, a couple minutes there, and pretty soon it all adds up ).

But sure, DIY for the 'grunt' stuff.

 

[mpire]

He may spend more than 45 minutes, but he only charges me for the standard call.

I trust him, he explains everything like Mr Wizard, and his thumbs up makes me feel good.

 

[mpire]

I picked up the tools last night at lowes....

....and I figured out its 1/2 inch copper, not 3/8ths.

So that makes me dumb.

I will have to go get a different bendy tool.

Damn.

 

[dmsween]

Tubing benders are inexpensive and work very good.

Although if you don't have one and need to do something right then I've used a baseball bat to bend some brake lines. The varying diameter of the bat is nice for different size bends.

 

[Interex]

 

[fabrk8r]

I picked up the tools last night at lowes....

....and I figured out its 1/2 inch copper, not 3/8ths.

So that makes me dumb.

I will have to go get a different bendy tool.

Damn.

Refrigeration copper is sized by O.D.

Plumbing copper is sized by I.D.

So what is 3/8" to a plumber is 1/2" to an HVAC tech.

 

[malibu101]

If this is a new mini-split the unit is pre-charged with the proper amount of refrigerant and refrigeration oil in the condenser section. After the connections are made, evacuated and leak checked the service valves are opened to release the charge into the evaporator section.

As has already been mentioned, this unit needs to be properly evacuated to a micron level of at least 500 microns to ensure no leaks and that all moisture and non-condensibles have been removed from the system.

I'm not a brain surgeon when it comes to refrigerent systems. So I have to ask this question.

IF the manufaturer "overfills" the condensor with refrigerent so there is enough to properly fill the evaporator I understand that although I've never heard if that.
Of course in this scenerio it must fill the evaporator AND lineset. Therfore I assume the lineset must be a specific length? Too much lineset length would create and undercharge and too little length too much charge.
What don't I know about a precharged setup like this?

 

[mpire]

It is pre-charged for a 25 foot lineset.

The manual will tell you one way or another depending on the manufacturer, but all the LG units I have seen are rated for 25 feet, and you will need to add refrigerant if you add length of tubing.

I have been practicing with this spring tube bender and its looking like it will do the job. The 9k unit had only 3/8ths inch tubing, where as the 18k unit has 1/2 inch tubing. So I have learned something it seems.

Now I have to figure out how to get it all to bed up pretty.

 

[malibu101]

It is pre-charged for a 25 foot lineset.

The manual will tell you one way or another depending on the manufacturer, but all the LG units I have seen are rated for 25 feet, and you will need to add refrigerant if you add length of tubing.
.

Thanks for the info.

 

[RKA]

I found lots of 90 and 180 benders for relatively little money which can handle up to 1/2" line. The problem comes when I need to bend 5/8" line...prices on those benders goes well over $100. Just now I found one called articco for under $40. These things are simple devices, how bad could it be to use this on for a few bends?
http://www.northwaysmachinery.com/productdisplay.asp?subcat=489

 

[chevelle67]

High side pressures can run 250 PSI and up. I would not try a regular compression fitting with that kind of working pressure. Refer tube is also not the same as water copper. Not sure the difference, but it's there.

if it's a new unit chances are it's 410a then your side routinely sees 450psi +. A lot of the new inverter mini splits have the metering device at the outlet of the condenser so both lines are low press, but with 410a the low side runs 125psi +.

 

[mrobins297aaa]

Refrigeration copper is sized by O.D.

Plumbing copper is sized by I.D.

So what is 3/8" to a plumber is 1/2" to an HVAC tech.

Actually I think the only sizes that are interchangeable are 3/4" water pipe and 7/8" refrigeration, they are the same size. the rest of those small sizes 3/8 1/2 5/8 none are interchangeable and would be a lose fit.

 

[mpire]

I was just wondering, don't all the mini-splits use compression fittings to connect the line-set anyway?