Mini split positive pressure test for leaks

[sdsurfer]

I am planing to install a 18k mini split this weekend and have been researching a lot about people pulling a vacuum on the lines to check for leaks. Others mention doing a positive pressure test with nitrogen. I do not have access to a nitrogen tank but I do have a small oil-less air compressor. When I was replacing my car AC components, I used it and my gauges to add pressure to the system to check for leaks.

Is there any downside to doing that with a mini split? I would of course vacuum the lines after confirming the system does not leak.

Pioneer does sell a “KWIK-E-VAC Line Set Flushing Kit for Mini Split Air Conditioning Systems” that seems like I can use to put pressure on the system but seems a little pricy for what it is.

Thank you

 

[428PI]

I used nitrogen and I still have a leak. I'm ready to try Pioneer leak sealer if I'm low next year.

 

[chris142]

If you can run your air through a water seperating filter first it's fine for a test like you described.

I dabble with auto ac repair at home and I have A tank of nitrogen I use to pressure test

 

[danski0224]

Your air compressor air will add a **** ton of moisture. If you do not use a micron gauge, you will not know when the evacuation is complete.

Besides the problem that the air compressor will not generate enough pressure to check for leaks per manufacturer instructions.

 

[sdsurfer]

I do have a water separator filter for when I spray car paint. Good idea, I can try that.

Who locally would sell nitrogen bottles if I wanted to look into it? HVAC place or welding place or ?

I just have a hard time justifying the $35 for the pioneer product that appears to be just a small amount of Freon and the instructions say to run it with one line disconnected to vent the gas, then close purge kit and quickly connect 2nd line. Seems strange.

 

[fitter30]

Should be a inert gas for a pressure test and should be at 500 lbs.

 

[pcmeiners]

"I do have a water separator filter for when I spray car paint."

Useless, as a separator only removes a small fraction of moisture in air

"I just have a hard time justifying the $35 for the pioneer product"

Would have a hard time justifying the Pioneer product if I was paid to use.

 

[sdsurfer]

@pcmeiners
“ Would have a hard time justifying the Pioneer product if I was paid to use.”

As in it sounds like a bad product that’s venting gas in the atmosphere for no reason? I checked the SDS and its R-152, which Google says (famous last words…) is similar to r-134. Which makes me think why don’t I just get a cheap can of r-134 to pressure test the system but I think I ready somewhere in the paperwork to not use r-134.

 

[pcmeiners]

"I'm ready to try Pioneer leak sealer"

If you use a leak sealer, you compromise the system and a warranty if you have one. Do it correctly and find the leak.

"Who locally would sell nitrogen bottles if I wanted to look into it?"
Hvac or Welding supply should have tanks. Ebay has some cheap regulators, but they need to be rated for 400-500 psi

 

[PoorUB]

You can use most any inert gas, CO2, Argon, nitrogen. Do you have any of these?

Compressed air is the worst thing you can use, even in automotive.

In a pinch, I might use propane, but be careful for the obvious reasons!

I can not think of any reason R134 wouldn't work, plus it is relatively cheap and available.

Back when R22 was cheap we used it often for leak checking, no matter what was in the system. Very useful if you have a refrigerant sniffer.

 

[428PI]

"I'm ready to try Pioneer leak sealer"

Pioneer is the brand of my minisplit. We were told to never use sealer in auto systems. I was leaking 1 can of freon a month or two in my 2003 tbird 8 years ago. I suspected the evap as everything else checked out. Put in sealer and haven't added any since. Ac works ok.

 

[American Locomotive]

The problem is you need a lot of pressure to adequately leak test a minisplit. At least 400 PSI or so. Most recommend 500+

 

[chris142]

I do have a water separator filter for when I spray car paint. Good idea, I can try that.

Who locally would sell nitrogen bottles if I wanted to look into it? HVAC place or welding place or ?

I just have a hard time justifying the $35 for the pioneer product that appears to be just a small amount of Freon and the instructions say to run it with one line disconnected to vent the gas, then close purge kit and quickly connect 2nd line. Seems strange.

welding place

 

[danski0224]

HVAC place or welding place or ?

Either.

You'll also need a regulator.