Installing mini-split AC issues :(

[louie]

So I finally found the time to install my mini split AC today. And it is really no big deal, some basic wiring, hang up the head unit, flare some copper, hook up the vacuum pump, and viola. Well, when I hooked up my vacuum pump and ran it for 45 min and then shut it off the gauge didn't stay at -30. So this means there is a leak somewhere in the copper connections. So I re-flare all four copper tube ends and run the pump again for 45 min. and then turn it off and it still will not stay at -30. Has anyone else experienced this? What should I do? I am very frustrated right now.

 

[swayzie]

take some oil, and put a thin coat of oil on the flares to help them seat properly.

and when your cutting and flaring, be sure to 100% debur the tubing and cut it really clean like.. use a file to straighten it out and debur.. most of the time, this is the cause of leaking flared connections.

any imperfection on the tubing will cause a leak.

 

[Guest 18340]

take some oil, and put a thin coat of oil on the flares to help them seat properly.

and when your cutting and flaring, be sure to 100% debur the tubing and cut it really clean like.. use a file to straighten it out and debur.. most of the time, this is the cause of leaking flared connections.

any imperfection on the tubing will cause a leak.

100% agree with this.
Also, make sure the fittings to/from the gauge and pump are tight.
And, make sure the flare fittings are nice an tight.
Did you make sure the inside of the flare is the correct size? The "shiny ring" on the inside of the flare has to be a specific width. The proper width size is listed in the instructions.
keep at it, you find the problem. Whatever you do, don't crack open those valves until that gauge holds a vacuum for at least 30 minutes or you will lose precious r410. Adding r410 to those things is a tricky procedure...

 

[louie]

Thanks for the tips and encouragement guys. Man, this easy project is turning in to a headache. I have been deburring the inside of the pipes, but haven't used a file. What kind of file do you use? And how tight do you crank on the attachements (every last ounce of muscle or just tight enough)?

 

[Guest 18340]

In between every last ounce of muscle and just tight enough...You could rent a torque wrench.
An easy way to check where the leak is; after you pull a vacuum disconnect the pump and open the valve for 2 seconds to let in some freon, then close it tight. Now the lineset is pressurized with r410. Spray soapy water on all your connections and look for bubbles.
Flares must be nothing short of perfect or they will leak.
Use this type of deburring tool;

The ones that are attached to the back of the pipe cutters are worthless.

 

[RipVanWeed]

Maybe your flare tool is not the right shape for fittings. I believe the lines and fittings for r410 are a different "flare" than those used for r40.

Just puttin' it out there.

Respect,

 

[Guest 18340]

Beat me to dude RipVanWeed! You are 100% absolutely correct.
louie, you need to use a flare tool for r410. I bought the "clutch type". Whatever type you buy though, it must state that it can be used for r410.
Great post RipVanWeed, K++

 

[louie]

Alright just about to approach round three, wish me luck lol. Nice, that is the same kind of deburring tool I bought.

 

[louie]

evlme2, so say I did want to do the pressurized freon test, is it the smaller tubing that I would open for 2 seconds (3/8'')?

 

[Guest 18340]

I opened the valve on the smaller tube, the gas valve.

 

[Cam]

Possibly the line set cracked somewhere inbetween the connections?

I know if you bend them back and forth a couple times or any really sharp turns they can crack/break. Gotta be really careful. Same with the connection between the indoor unit and the lineset. Mine said to actually bend it a certain direction (and only once) or it would potentially break.

Edit: Its probably the flaring though...just thought I'd add in another possibility if you haven't considered it.

 

[louie]

My nightmare continues. So after reflaring each end about 4 times, I was really fed up with the whole process, so I called a local HVAC shop and had them flare each end for me. Well, I hook up the vac for like 45 min. and then turn it off and it still slowly drops from -30 to -10 and then stays at -10 for a minute and slowly goes to 0. I just don't know what to do. I can't have an HVAC guy come out. What really sucks is this is holding up me finishing my new room. Now, I have got a leak somewhere, and I know an HVAC guy would hook up bottled nitrogen and pressurize the linset and then use a soap solution to check for leaks. Since I have bottled Co2, do you think I could essentially hook up the Co2 to the lineset instead of nitrogen and then check for leaks? Any other suggestions? I am dumb founded.

 

[Guest 18340]

Did you try releasing some gas into the line set and checking with soapy water? Thats what I did to check for leaks.
I'm beginning to wonder if the "leak" is at the the pump and not the flares...
If you will, explain the exact way you're hooking up your pump and gauges. You had an hvac shop flare your lines so I'm wondering if the "leak" is somewhere else.
Let's put it this way, it could only be at the flare connections or the connections for the pump/gauges. Since you flared and reflared so many times, I would suspect the other connections.

 

[louie]

Thanks for the help evlme2. I have it hooked up just like the manual picture shows: I have the lowside of the gauge set knob opened and hooked up to the 3/8" lineset, and the connection in between the low and high side on the gauge set hooked up to the pump. I have been thinking that maybe it is the pump as well. No I didn't open the line set yet, I am saving that for an absolute last resort because I heard that once they apen sometime they don't always close again 100%.

 

[Smokerman]

I assume your'e closing the guages before you turn off the pump?

 

[Guest 18340]

Don't worry, the valve will close 100% again. All you're doing is cracking it for 1 second, just enough to pressurize the line. But yeah, leave that as the last resort.
I suspect the "leak" is in your equipment somewhere.
Smokerman asks a good question.

 

[louie]

Whooooow!!!! Yesssssss! So to destall the head unit and check the L shaped pipe that connects in to the head unit and then connects again to the linsets, and when I inspected the factory flared end it looked a little bit "sketchy", so I cut it off and re flared it ( I think I am a pro by this point lol and added a little oil) and hooked everything back up and viola, Im holding steady a -30!!! I am super pumped right now. I can now finish my new room this weekend. I have to thank everyone that helped me troubleshoot this headache. Have a great weekend everyone and stay cool, my girls will be now that I have the AC rockin!

 

[Guest 18340]

HELL YEAH!!!!
Good for you brother! Congrats!
Please come back and let us know how things are once you fire her up.
You're gonna loooooooove that Mr.Slim.