Mini Split? Line set bending and torque of flare nut

I'm looking for some advice from those who have gone before me on line set bending and if anyone has torqued the flare nuts or was a suction test good enough?

You know, every piece of literature I've read says to use a torque wrench on the flares.
Too tight and you'll crack the tubing, too loose and kiss away the precious r410.
My first mini install I did not use a torque wrench. It's been 2 years now and no leaks, so I got lucky.
I'm about to do another install and this time I'm getting a torque wrench. Why? I've decided not to take anymore unnecessary chances in my life.
The line set. You can bend it easy enough but use kid gloves when doing so. Gradual bends, etc.

I just got done installing mine. I wouldnt worry to much about bending the line. I was able to get a pipe bender for about $12 and it worked fine. Just go slow and take your time. I bought a pump and did a vacuum test and found a slow leak. I didnt want to over tighten the wrong one so i pulled a vacuum to -40psi and released the refrigerant. I used some soapy water, found and fixed the leak within 30seconds of releasing the refrigerant and everything has been working perfectly for about 2 weeks now.

Definitely get the vacuum pump. If i were to do this again i would get the torque wrench, but i was able to do it without one. My instructions were also in spanish so i didn't relies i was suppose to use one until after i had already installed it.

Also another key peace of info i found out is that most units come pre charged with enough refrigerant to fill a 25ft line set. IF you change the length of the line set you need to add or remove some refrigerant... I just kept the 25ft length to avoid all this.

Good luck.

evlme2 said:

I'm about to do another install and this time I'm getting a torque wrench. Why? I've decided not to take anymore unnecessary chances in my life.

Click to expand...

Great advice.
Evlme2 helped me out a ton when I was installing mine.

I tried using a pipe bender but had a hell of a time because the line set comes with insulation slipped on from the factory before they flare.

Yeah i just took a box cutter and sliced a cut into the insulation to do the bends. I was too paranoid to just "trust" i didnt crimp it. Then i just taped the insulation back up. But you could definitely get away without a pipe bender.

Thanks for the input.

I just found a pair of crows foot wrenches to adapt onto my torque wrench at Northern Tool, nobody else had them in stock..and even then sit down before you hear the price.

I've had bad luck with copper tubing in the past. The suction line on my 1.5ton unit is 1/2". The tubing bender at the big box stores only goes to 3/8", and the 1/2" models I cold find online are a little to spendy.

If it comes down to it, and the line gets kinked I will cut in a half inch 90 and reflare the end.

I went with the 15' line set with the idea that if I had a leak initially I would have more gas than needed, and could bleed it down to proper operating pressure if its on the high side.

Any other install advice is welcome......I'm all ears.

caljim- LOL you cant bleed refrigerant out without having a recovery cylinder...bleeding refrigerant out allows air to be sucked in

ya and you need a vaccuum pump, you cant just get away with not using one

its amazing at how people love to state their opinions like fact!

you can use a strong can to bend the pipe around it to make 90 degree turns

i have also never used a torque wrench, just crescent wrenches....just make em snug and check for leaks...its not rocket science

i wouldnt talk to much about "bleeding" R410a into the air... I think i heard thats something like a $10,000 fine, granted someone would have to catch you. But just a heads up.

https://www.icmag.com/ic/showthread.php?t=230770
Thats the tread i started when i did mine.

BigBuck said:

Yeah i just took a box cutter and sliced a cut into the insulation to do the bends. I was too paranoid to just "trust" i didnt crimp it. Then i just taped the insulation back up. But you could definitely get away without a pipe bender.

Click to expand...

My first mini split came with a line set that had a white insulation. It was yellow foam with a white plastic wrap glued to it. Also, I didn;t make any serious bends. This time the line set has the black foam and I'm def gonna strip it off so I can see my bends. No more chancing things!

caljim said:

Thanks for the input.

I just found a pair of crows foot wrenches to adapt onto my torque wrench at Northern Tool, nobody else had them in stock..and even then sit down before you hear the price.

I've had bad luck with copper tubing in the past. The suction line on my 1.5ton unit is 1/2". The tubing bender at the big box stores only goes to 3/8", and the 1/2" models I cold find online are a little to spendy.

If it comes down to it, and the line gets kinked I will cut in half inch 90 and reflare the end.

I went with the 15' line set with the idea that if I had a leak initially I would have more gas than needed, and could bleed it down to proper operating pressure if its on the high side.

Any other install advice is welcome......I'm all ears.

Click to expand...

What brand/model mini split is it?
I ask because some brands are very specific about line set length and amount of r410. Lg clearly states you have to add or subtract an X amount of r410 if the line set is longer or shorter than 25'.
The Mitsubishi only states to add if exceeding 25', nothing about subtracting if going shorter.
Mind you, 410 must be WEIGHED IN/OUT. It's not as easy as cracking the valve and letting out a little. You have to know how much to add/remove and to that that you need an hvac scale and r410 bottle.
I would send back the 15' and get the 25'

My line set had the black insulation and i would try and leave it on if i were you. Might be a pain in the ass to put it back on and just putting a slice the length of the bend in the insulation worked out great for me. Gave me plenty of room to slide the insulation to the side and get my pipe bender in there to bend the line.

I would also get the 25' line set. It seams like if you plan on changing how much R410a you have in the unit, you are going to have to call a tech.
Even if you do find a way to adjust to the proper amount of R410a its an extra, unnecessary, and avoidable step which just leaves more room for mistakes.

evlme2 said:

...
Mind you, 410 must be WEIGHED IN/OUT. It's not as easy as cracking the valve and letting out a little. You have to know how much to add/remove and to that that you need an hvac scale and r410 bottle.
I would send back the 15' and get the 25'

Click to expand...

This only applies in the winter. In the summer just use subcool or superheat measurements, no weighing required, hell, a good tech can even use superheat/subcool in the winter if they know their shit, but I would not advise it unless you are in an emergency situation. And yes, if you shorten your lineset, your system will be overcharged, but, the amount of overcharge would be so minuscule that I would not worry about it too much.

what type of mini-split is it? what does the installation manual say?

lol

ya overcharging blows seals in compressors and doesnt work

fucking idiots

you shouldnt be posting shit that you just come up with like they are facts...you are going to help someone damage their system

you shouldnt be playing with a system charge unless you have guages, nitrogen, and a recovery tank...and you know what you are doing!

slowride said:

lol

ya overcharging blows seals in compressors and doesnt work

fucking idiots

you shouldnt be posting shit that you just come up with like they are facts...you are going to help someone damage their system

you shouldnt be playing with a system charge unless you have guages, nitrogen, and a recovery tank...and you know what you are doing!

Click to expand...

Well duh, if you overcharge by pounds yes, a couple of ounces, nope, nada, ain't gonna happen. Been doing this way to long to buy what you're trying to sell.

All good info here.

I got the wrenches from Northern Tool and they had a simple tubing bender that will do up to 1/2" for $7, perfect.

Thanks for the heads up on the line set. I have a
Mitsubish 17.2btu @19.2 seer.

Looks like I will be getting a new line set, it would be nice to do it right the first time.

What he said. My HVAC guy told me the systems come with enough r410 to go 50' without losing effiency. There's room in the system for a little variance.

The key for the DIY guys to remember is "x" grams of refrigerant one way or the other means little. It's way more important to have no air in the system. I installed the lineset supplied with the unit. It was shipped from Grainger direct. One of the flares was poorly made and failed to hold pressure resulting in a small leak. I had hired a HVAC guy to comeout and vaccum the lines. the system held a vaccum, but started to leak later that day. Back out he came, recovered the 410 and reflared the lineset.

He presumed I had overtorqued the fitting, I actually had him check the torque before proceeding and I was right in there. When we cut off the failed end and the misflare became apparent....I said HA. 30 yrs running a bigass printing press gives a guy a pretty good feel for torque. When the leak was spotted I had very slightly tightened the fitting alittle more, to no avail.

I should have inspected the flares better. the linesets had capped ends and were supposedly shipped with nitrogen in them. I had left the caps on until just before attaching, avoiding any moisture or humidity getting in lines.

Researched making my own lineset but was discouraged doing so by all the tools needed. This A/C stuff takes a little different flare than the tools I have. Once I decided to use an HVAC tech to vaccum the lines, I shelved the DIY lineset idea.

The guy that came to my place had no interest in the indoor unit as I had specificly hired him to vaccum the lineset. I hustled in and out operating the system for startup and recovery modes. Iff'n your trying this be sure to read up on the initial startup procedures and where any hidden buttons may be so you can keep a step ahead of the tech. Also helps to have a couple of hairtrigger Aust. Shepards inside barking whenever they hear his voice.

Some HVAC co's didn't want to talk to me because of the selfinstall, but the guy that came out said my work was way better than the average HVAC installer. Kinda got F'ed by the faulty flare cause I had to pay the guy to come out again rightaway to help me with the leak.

Get the torque wrench....sleep better

Respect

Is the flare any different than the standard big box store flare tool would make?

Yeah, I think so.

We'll get an expert to chime in on this.