Question about pressure testing Mini Split

[newpain01]

I installed a mini split in my garage last year and it worked fine for 6+ months and then stopped. When I turn it on, the fan kicks on but not the compressor. I suspected that the refrigerant leaked out, so hooked up some gauges and it's shows 0 psi, guess that's why the compressor doesn't turn on. It's should have 17oz of that eco gas, R32.

Called a couple HVAC guys and they do not want to work on DIY mini splits. The other day I found a guy who said he can refill it after I fix the leak, but other than that he doesn't want to work on it to find the leak or do a pressure test.

I know they use nitrogen for pressure testing, but I don't have any and don't really want to spend $200+ to get a tank just for this one time use.
I do have a lot of CO2 and two tanks of pure argon for welding, so I am wondering if I can use those for the pressure test. I heard CO2 is not recommended because it might have moisture but I want to hear opinions if anyone used argon or CO2.

If so, what kind of adapter do I need to connect the regulator to the HVAC gauges (yellow hose) and what pressure do I need for the test? He told me if I am using nitrogen to get it to 300psi and listen for hissing.

Any help appreciated!

 

[462867aa]

I have used argon on my ac units. Worked just fine. For me it was better than buying a nitrogen tank for a small amount of use.

 

[newpain01]

I have used argon on my ac units. Worked just fine. For me it was better than buying a nitrogen tank for a small amount of use.

Thanks! That's my point too, I already have the argon. How did you connect the HVAC manifold to the argon regulator and what pressure did you use?

 

[danski0224]

If so, what kind of adapter do I need to connect the regulator to the HVAC gauges (yellow hose)

A nitrogen regulator has a SAE flare fitting for the A/C charging hoses. If you will not be using a N2 regulator, then you may need to remove the existing low side fitting on the regulator that you have or will use, and get a low side fitting that will work.

and what pressure do I need for the test?

The individual components will have a test pressure specified on the product label. That is the information you need.

He told me if I am using nitrogen to get it to 300psi and listen for hissing.

I would not assume the pressure number without verifying on YOUR equipment. I would not take random advice from random strangers on the internet about the proper test pressure for your piece of equipment. I have seen anything fro 250 to 700 psi specified as a test pressure, and the duration is typically 24 hours.

I would also not assume that you will be able to hear the leak.

You may be able to see evidence of a leak by oil staining. If I was a betting person, my money would be on a leaking flare connection, or two. It isn't easy to make a GOOD flare that doesn't leak. They leak/fail when people do not use a torque wrench as specified by the manufacturer. Leaking flare connections have ALWAYS been oily in my experience.

If it is leaking in the evap or condenser coil, you are probably screwed.

The people you talked to do not want to mess with finding the leak because it can be a pain in the ***. It very quickly escalates into a whole lot of money at customer pay rates.

You may want to find an installation and operating manual and read it to see if there is a service mode that is required in order to recover refrigerant, pressure test or install refrigerant. Doing it wrong will **** up the equipment. Some new equipment is "preset" from the factory, and it all changes when power is applied for the first time.

 

[Firebrick43]

I installed a mini split in my garage last year and it worked fine for 6+ months and then stopped. When I turn it on, the fan kicks on but not the compressor. I suspected that the refrigerant leaked out, so hooked up some gauges and it's shows 0 psi, guess that's why the compressor doesn't turn on. It's should have 17oz of that eco gas, R32.

Called a couple HVAC guys and they do not want to work on DIY mini splits. The other day I found a guy who said he can refill it after I fix the leak, but other than that he doesn't want to work on it to find the leak or do a pressure test.

I know they use nitrogen for pressure testing, but I don't have any and don't really want to spend $200+ to get a tank just for this one time use.
I do have a lot of CO2 and two tanks of pure argon for welding, so I am wondering if I can use those for the pressure test. I heard CO2 is not recommended because it might have moisture but I want to hear opinions if anyone used argon or CO2.

If so, what kind of adapter do I need to connect the regulator to the HVAC gauges (yellow hose) and what pressure do I need for the test? He told me if I am using nitrogen to get it to 300psi and listen for hissing.

Any help appreciated!

What brand and model is it?

 

[newpain01]

What brand and model is it?

It is some random Chinese brand named Yitahome.

 

[danski0224]

For $600 bucks, I would just buy a new one. And follow the installation instructions.

Odds are, they will not honor the warranty if the evap/condenser coil is bad.

If you used the factory flare fittings out of the box, then that's where it failed.

 

[newpain01]

A nitrogen regulator has a SAE flare fitting for the A/C charging hoses. If you will not be using a N2 regulator, then you may need to remove the existing low side fitting on the regulator that you have or will use, and get a low side fitting that will work.

The individual components will have a test pressure specified on the product label. That is the information you need.

I would not assume the pressure number without verifying on YOUR equipment. I would not take random advice from random strangers on the internet. I have seen anything fro 250 to 700 psi specified as a test pressure, and the duration is typically 24 hours.

I would also not assume that you will be able to hear the leak.

You may be able to see evidence of a leak by oil staining. If I was a betting person, my money would be on a leaking flare connection, or two. It isn't easy to make a GOOD flare that doesn't leak. They leak/fail when people do not use a torque wrench as specified by the manufacturer. Leaking flare connections have ALWAYS been oily in my experience.

If it is leaking in the evap or condenser coil, you are probably screwed.

The people you talked to do not want to mess with finding the leak because it can be a pain in the ***. It very quickly escalates into a whole lot of money at customer pay rates.

You may want to find an installation and operating manual and read it to see if there is a service mode that is required in order to recover refrigerant, pressure test or install refrigerant. Doing it wrong will **** up the equipment. Some new equipment is "preset" from the factory, and it all changes when power is applied for the first time.

Not much info on them honestly. There is a manual but it's just basic stuff. If I screw it up, I'm not going to fret about it. I thought, I already have the argon, see if I can pressure test it, re-check the flares and put some Nyloc and get it filled for $100.

 

[newpain01]

For $600 bucks, I would just buy a new one. And follow the installation instructions.

Odds are, they will not honor the warranty if the evap/condenser coil is bad.

If you used the factory flare fittings out of the box, then that's where it failed.

I actually paid $400 for it. It's not about the money, it's about the effort of going through it again. It was already installed and was running fine, so if I can get it fixed, I prefer to do that instead.

Also, it's not my first mini-split install, I have installed another one 2yrs ago and it's been running great since. I went through the instructions but I think I might have overtightened the connections and might have a leak there. I don't have one of those hvac torque wrenches.

 

[danski0224]

Not much info on them honestly.

Design pressure- something to not exceed. It's there.

 

[newpain01]

Design pressure- something to not exceed. It's there.

Yeah, saw that. Thanks!

 

[todd_fuller]

You can look for a purge regulator. Some have presets for purging for brazing and for pressure testing. I don’t know if N2 bottle share the came tank fitting but the regulators for nitrogen are fairly inexpensive.

https://www.amazon.com/VN-500-Nitrogen-Control-Regulator-Purging/dp/B0DCMLKTNF/?tag=atomicindus08-20

You can buy those cheap manifolds, but for a minisplit, there is only one connection. I would recommend a wireless probe. You’ll also need a valve core removal tool and you can get ones that have the 5/16 flare for minisplits which also have two 1/4 flare connections (one for nitrogen and one for probe). The knock off valve core tools are probably fine, I think it’s on vacuum that the name brands work better.

I’ve seen videos showing techs use windex for leak detection. Make sure you cap the service port if you want to check the schrader valve.

 

[danski0224]

Might be obvious, might not be... but you do not want to exceed the lower value if the system is open and connected.

 

[WildBill]

You could potentially buy one of these purge kits to test for leaks, I've seen them as cheap as $30.

https://www.homedepot.com/p/Pioneer-KWIK-E-VAC-Line-Set-Flushing-Kit-for-Mini-Split-Air-Conditioning-Systems-IKT-KEV-10-516/314537728#see-more-details

 

[newpain01]

You could potentially buy one of these purge kits to test for leaks, I've seen them as cheap as $30.

https://www.homedepot.com/p/Pioneer-KWIK-E-VAC-Line-Set-Flushing-Kit-for-Mini-Split-Air-Conditioning-Systems-IKT-KEV-10-516/314537728#see-more-details

This looks like something used instead of a vacuum pump is that right? I do have this set with a vacuum pump, gauges and a leak detector. When I installed it I pulled vacuum and held it for 30 min without changes.

 

[Firebrick43]

You can look for a purge regulator. Some have presets for purging for brazing and for pressure testing. I don’t know if N2 bottle share the came tank fitting but the regulators for nitrogen are fairly inexpensive.

https://www.amazon.com/VN-500-Nitrogen-Control-Regulator-Purging/dp/B0DCMLKTNF/?tag=atomicindus08-20

You can buy those cheap manifolds, but for a minisplit, there is only one connection. I would recommend a wireless probe. You’ll also need a valve core removal tool and you can get ones that have the 5/16 flare for minisplits which also have two 1/4 flare connections (one for nitrogen and one for probe). The knock off valve core tools are probably fine, I think it’s on vacuum that the name brands work better.

I’ve seen videos showing techs use windex for leak detection. Make sure you cap the service port if you want to check the schrader valve.

Got to love that AI advertising. Showing a brass manifold sectioned as "copper tubing" and a steel pipe full of poo if you don't purge. LOL

 

[Firebrick43]

I actually paid $400 for it. It's not about the money, it's about the effort of going through it again. It was already installed and was running fine, so if I can get it fixed, I prefer to do that instead.

Also, it's not my first mini-split install, I have installed another one 2yrs ago and it's been running great since. I went through the instructions but I think I might have overtightened the connections and might have a leak there. I don't have one of those hvac torque wrenches.

A regular torque wrench with a crowsfoot will work, just position the crowsfoot at 90 degrees to either side to maintain very close to the correct torque.

 

[newpain01]

A regular torque wrench with a crowsfoot will work, just position the crowsfoot at 90 degrees to either side to maintain very close to the correct torque.

Didn't think of that but that is a great idea, thank you! I do have a regular torque wrench, just need to grab some crowsfoot.