Question on Nitrogen test requirements

[motterpaul]

What exactly is required to do a good nitrogen test on a mini split?

Or in other words, if I want to do a nitrogen test, what exactly do I need to acquire to do it.

How much nitrogen (16-ft line set) or what size tank.

Should it pressurized up to a certain amount, or is that a limited by the valve?

Can you buy nitrogen in a tank, or do you need to buy the tank and get it filled?

Can you rent this?

 

[jjrbus]

You can go to a welding supply place and buy a small tank of nitrogen for depending on where you are around $100, I believe they are 20 cu ft and should come filled. You will need to buy a nitrogen gauge separately that is good up to the psi spec'ed by your manufacture. Daikin was 625 PSI.

I am a You tube certified hack and do it this way. I leave the liquid port loose and start the nitrogen flow till I hear it hiss at the valve, shut off the nitrogen and then torque the liquid line to spec. This takes very little gas and is unprofessional but I now know I have an open system.

To avoid wasting gas due to something wrong I add 50/75 psi to the system, turn the nitrogen off and watch the gauge for 30 minutes. If psi remains stable then I increase the psi in 100 psi steps about 30 minutes apart. If something does let go I am not out a lot of nitrogen. The longest I have left the nitrogen set was 3 days as I as doing other things. The psi will rise and fall a few psi due to temperature, shade sun. I am not a pro, I can take as long as I want to install and test.

Now if you want to go all out Google triple evacuation, I do not want to type it all out.

 

[motterpaul]

Thanks for the info on where to get nitrogen. I did watch the triple evac video - understood.

My manufacturer (Pioneer) does not mention the nitrogen test in its install manual, but as referenced below, a longer install video says the pressure can be different for the inside unit than the outside, so he recommends 300 PSI for all mini-splits.

It is these kinds of questions that are not spec'd in the manual that make doing this the first time so hard. I guess this is one reason a lot of guys apprentice. I do like the tip of doing smaller PSI tests first.

So, when you say this "I leave the liquid port loose and start the nitrogen flow till I hear it hiss at the valve, shut off the nitrogen and then torque the liquid line to spec. This takes very little gas and is unprofessional but I now know I have an open system."

The lines are empty, so this way you also know you are filling the whole line set, not just the hose. I just saw a message a from a DIY who said when he did the vacuum he forgot to open the lineset, so he just vacuumed his hose.

THOSE are the things that are logical, but potential pitfalls for people who have never done it.

This recommended longer install video is good because he does mention every small step he does along the way.

 

[motterpaul]

What kind of nitrogen do I need? I see, dry, liquid, no oxygen, food grade.... etc.

What should I look for? Thanks again

 

[jjrbus]

One of the reasons I did not buy the big dollar systems is not wanting to waste a ton of money if I screwed them up!

The reason I did not buy the lower dollar systems was poor instructions a lack of parts and technical support. Daikin stood out for being in the middle with great support.

I do not understand how some systems can not spec a nitrogen test while all the systems are virtually the same.. Need to be careful with videos, R410 and mini splits have not been around a long time and many instructions are still for R22 which runs at a much lower pressure and is more forgiving.

I bought my nitrogen gauge off Amazon. If you want to sell should be able to recoup most of your money when done. Good luck.

 

[jjrbus]

What kind of nitrogen do I need? I see, dry, liquid, no oxygen, food grade.... etc.

What should I look for? Thanks again

I do not know, I went to a welding supply place and asked to buy a tank of nitrogen. You may not get a new tank, when the tank is empty it is taken back and exchanged.

 

[motterpaul]

So whatever they use for welding is it, I guess. I don't know if I can buy it in CA. Every web site I looked at asked for pro credentials.

 

[LS6 Tommy]

What kind of nitrogen do I need? I see, dry, liquid, no oxygen, food grade.... etc.

What should I look for? Thanks again

You need dry. Don't be tempted to use compressed air.

Tommy

 

[Rc_Guy]

The neighbor that did mine bought nitrogen for about $36.00 he already has the gauge setup though

 

[motterpaul]

You can buy the smallest tank for about $104 here in San Diego - then they will fill it for you (they actually just do an exchange) for a little over $10.

 

[Jim greengo]

You can go to a welding supply place and buy a small tank of nitrogen for depending on where you are around $100, I believe they are 20 cu ft and should come filled. You will need to buy a nitrogen gauge separately that is good up to the psi spec'ed by your manufacture. Daikin was 625 PSI.

I am a You tube certified hack and do it this way. I leave the liquid port loose and start the nitrogen flow till I hear it hiss at the valve, shut off the nitrogen and then torque the liquid line to spec. This takes very little gas and is unprofessional but I now know I have an open system.

To avoid wasting gas due to something wrong I add 50/75 psi to the system, turn the nitrogen off and watch the gauge for 30 minutes. If psi remains stable then I increase the psi in 100 psi steps about 30 minutes apart. If something does let go I am not out a lot of nitrogen. The longest I have left the nitrogen set was 3 days as I as doing other things. The psi will rise and fall a few psi due to temperature, shade sun. I am not a pro, I can take as long as I want to install and test.

Now if you want to go all out Google triple evacuation, I do not want to type it all out.

Where did you find a regulator good for 675psi?

 

[chinboys]

Pressure test with a regulator that can pressurize the isolated supply and return lines up to 500 psi on the 410 freon-based mini-split systems in a few increments (300, 400, and 500 PSI) for some duration of time.
The systems (condenser and evaporator) are designed for such pressure.
As well as the line set that goes in between them.

The modern 410-based freon systems operate at higher pressure relative to those based on the R-22 or R-134 types of freon,

If your flares or silver solder connections are not up to specs at 500 PSI, you will know.

And one would not be using that much more Nitrogen to test with relative at 200 psi to that of 500 psi.

 

[motterpaul]

Where do you get a canister of nitrogen in order to do a mini-split pressure test? I have read hobby stores, welding supplies, are there any other options? Should I expect to spend $110 on a canister and $20 to fill it? Also, Dry Nitrogen is N2, right?

 

[mbunimog]

you go to your local welding gas supplier to get a small 20 cf bottle of nitrogen. Just did that a few days ago. Cost was about 150 dollars. Got the regulator and hose on Amazon about 35 dollars

 

[Walkers]

You need dry. Don't be tempted to use compressed air.

Tommy

I always am, and since it would be evacuated, what is the issue. I am genuinely curious, not trying to be a pita.

 

[bluedog225]

You will introduce contamination.

 

[metlmunchr]

I always am, and since it would be evacuated, what is the issue. I am genuinely curious, not trying to be a pita.

Addressing the question from the standpoint of mini splits, you wouldn't have sufficient pressure for testing the flared connections with the max output pressure of any normal air compressor. Leaky soldered or brazed connections will leak at most any pressure, but flared connections are more likely to leak as the applied pressure is increased, hence the recommendation to test at pressures at least equal to the highest pressures the joints will see in operation.

In general, if you were going to test any refrigerating system with compressed air, assuming the pressure is adequate, you'd need a coalescing filter and a desiccant dryer on the air line to make sure the air is both dry and oil free. Moisture that's trapped under an oil film can be difficult to remove by evacuation, and any oil introduced via the compressed air would be considered a contaminant as it would almost certainly not be a refrigerant compatible oil.

If you do any mig or tig welding, gases like argon, 75/25, and CO2 are also suitable for testing without having to buy a nitrogen cylinder and contents that may have no further use in the future.

 

[Walkers]

Addressing the question from the standpoint of mini splits, you wouldn't have sufficient pressure for testing the flared connections with the max output pressure of any normal air compressor. Leaky soldered or brazed connections will leak at most any pressure, but flared connections are more likely to leak as the applied pressure is increased, hence the recommendation to test at pressures at least equal to the highest pressures the joints will see in operation.

In general, if you were going to test any refrigerating system with compressed air, assuming the pressure is adequate, you'd need a coalescing filter and a desiccant dryer on the air line to make sure the air is both dry and oil free. Moisture that's trapped under an oil film can be difficult to remove by evacuation, and any oil introduced via the compressed air would be considered a contaminant as it would almost certainly not be a refrigerant compatible oil.

If you do any mig or tig welding, gases like argon, 75/25, and CO2 are also suitable for testing without having to buy a nitrogen cylinder and contents that may have no further use in the future.

Thanks, I was unaware of the oil film issue. That last piece is good to know. I always have argon, 75/25, and CO2 on hand.

 

[mcbane]

Where did you find a regulator good for 675psi?

Grainger has a full range of regulators with max outlet pressure as high as 4000 psi.

 

[Jim greengo]

Mine tops out between 400-500,I'd be worried running much more pressure than that through a rubber hose myself.hahaha

 

[98ssuck]

You will need to buy a nitrogen gauge separately that is good up to the psi spec'ed by your manufacture. Daikin was 625 PSI.

Did you pressure test your Diakin Line set and indoor unit to 625 psi? That sounds like the max design pressure. In my jurisdiction(bc, Canada) we are required to do tests of 2hrs of the saturated pressure of 125*f on the high side Which for 410 is somewhere below 500psi.

In general testing at the max design pressure is overkill. Don’t forget to record the ambient temperature while pressure testing to account for fluctuations in temperature causing pressure to drop.

 

[jjrbus]

Did you pressure test your Diakin Line set and indoor unit to 625 psi? That sounds like the max design pressure. In my jurisdiction(bc, Canada) we are required to do tests of 2hrs of the saturated pressure of 125*f on the high side Which for 410 is somewhere below 500psi.

In general testing at the max design pressure is overkill. Don’t forget to record the ambient temperature while pressure testing to account for fluctuations in temperature causing pressure t

 

[jjrbus]

I purchased my regulator off Amazon 2/23/18, good to 800 psi. I checked no longer available.

The Daikin install manual state to test to 625 psi so that is what I tested to! Looks like waaaaay too much but if something goes wrong I did the best I could to get it right!

 

[pcmeiners]

What is the talk about nitrogen regulators? ANY new regulator off Ebay with the proper tank connector, rated over the test pressure needed will work. Cheapest to the most expensive, your choice, does not make any difference except to your wallet. Search Ebay for ,.... welding gas regulator nitrogen

As to using compressor air from a home compressor, you could not use/afford enough filters to removed all the contaminates from a home based compressor. Contaminates such as oil, acids such as Sulfuric and Nitric and everything in our atmosphere, no less a good bit of moisture which expands 1700 times ( great for extending vacumn pump time)

 

[motterpaul]

I got the tank - it is brand new. I hope that when I get a filled replacement it looks as good as mine does (cost $100). My regulator is rated up to about 600 psi. I did see some cheap ones that only said 200 psi.

Yes, you need dry N2 nitrogen. I started with a 20 Cu Ft tank.

 

[PCustoms]

I got the tank - it is brand new. I hope that when I get a filled replacement it looks as good as mine does (cost $100). My regulator is rated up to about 600 psi. I did see some cheap ones that only said 200 psi.

Yes, you need dry N2 nitrogen. I started with a 20 Cu Ft tank.

Unless I'm an idiot, you posted a gage.

That nitrogen tank should be well over 2000psi, you need a regulator to, well, regulate that down to a working pressure.

 

[FrancisJ]

I'm certain many of you aren't certified (I'm EPA 609 (so I can buy bulk refrigerants), ASE, others) and hear this stuff about DIYrs playing with Nitrogen, refrigerants. Don't and please also stop dumping refrigerants in the atmosphere -- some of that chit we're putting up there (e.g. C02) stays there for hundreds of years, thousands of years in some places -- we're starting to cook this place and it's time to chill the F out -- char some mammal flesh on the barbie as an alternative and leave the HVAC to pros.

 

[motterpaul]

Unless I'm an idiot, you posted a gage.

That nitrogen tank should be well over 2000psi, you need a regulator to, well, regulate that down to a working pressure.

Sorry, I had several windows open at once and put the wrong link in. Here is my regulator. As far as playing with nitrogen, I know it is inert and already 72% of our atmosphere. The coolant will be loaded by a professional.

 

[motterpaul]

Got my nitrogen, finally. AirGas wouldn't create a new account for me online, so I called and they sounded sketchy when I said I needed it to test an AC (I'm in CA). But I finally just drove up there with a new tank and asked to swap it out for me without saying why. $40 for the fill plus the new tank, kind of pricey but I least I got it.

 

[bluedog225]

CO2?

 

[LS6 Tommy]

CO2?

Absolutely not. What do you the the "O2" in "CO2"is?

Tommy

 

[Dagny]

I can get extra dry nitrogen here so that it what i use

 

[metlmunchr]

CO2?

Absolutely not. What do you the the "O2" in "CO2"is?

Tommy

So how about explaining what's wrong with using CO2 for testing? Don't know what you think the O2 in CO2 is, but it isn't free oxygen in a form separate from the carbon atom it's bonded to.

If there's moisture in the system, it will combine with CO2 under pressure and form carbonic acid, the same stuff that makes soft drinks fizzy. When the pressure is relieved, carbonic acid dissociates back into the original CO2 and moisture, ready to be evacuated along with any other non condensibles in the system.

 

[fitter30]

Co 2 is to wet. Welding supply just ask for nitrogen. Buy a reg off the net at least 500 lbs. Test first at 100 then if it passes 500 for at least 10 hours. Nitrogen is a inert gas thats dry and doesn't change much with temp. Look around for a used tank gas supplier charge for testing it anyway and u will get a old tank filled even if bought new.

 

[like2wheel]

Anything wrong with using argon?
How about for purge while brazing?