Question for those who nitrogen test mini splits

[shaggyant]

What does your pressure test gauge setup look like? I am curious as I don’t have nitrogen on hand but I do have copious amounts of argon for welding purposes. Seems like this would fit the bill great if I don’t end up spending tons on adapters or special regulators.

Also, when you do the nitrogen test what percentage of the time do you end up detecting a leak? Are leaks a frequent thing to find even after properly making up the connections?

 

[American Locomotive]

I use argon, because it's just what I have handy. I bought a cheap HVAC "nitrogen" regulator online. It has the right fitting to go to a standard HVAC gauge set.

I hook the bottle up to middle port on the manifold, the red high side hose to the minisplit. I then charge it up to 500 PSI, close the manifold & tank valves, make a little mark on the gauge. I come back tomorrow morning to see where were are at.

This process is temperature sensitive. So it's best to make sure your interior temperature (where the coil, and majority of test gas is) stays consistent. Additionally, the gas will heat up when you charge it into the split, so you may want to recheck after 5-10 minutes and give it a little top-up if necessary. I usually spray down the joints with soapy water. If it all seems good, I'll come back the next day.

 

[pcmeiners]

If hoses are between your king value connection and your gauge there is a good chance of leakage from the hose so try to setup your test as below if possible; it is not often your hoses remain totally leak free. Personally I use blue Loctite on all king valve threaded connections, tiny bit behind the flare, Including on the caps threads when testing is done, and gas is released .

"Are leaks a frequent thing to find even after properly making up the connections?" After properly making the connection, almost never, but add a bit of tiredness, laziness,or bad weather to the mix, all bets are off. Argon is good.

 

[462867aa]

Used argon on mine because I had it. Worked fine.

 

[dlwilson]

I use argon for auto AC testing. I don't do it often, so I don't have a dedicated setup. I use the argon tank from the tig, and the regulator from the mig, and an adapter that allows me to connect my R134a gauges to the mig regulator.

 

[kaymccampbell]

What does your pressure test gauge setup look like? I am curious as I don’t have nitrogen on hand but I do have copious amounts of argon for welding purposes. Seems like this would fit the bill great if I don’t end up spending tons on adapters or special regulators.

Also, when you do the nitrogen test what percentage of the time do you end up detecting a leak? Are leaks a frequent thing to find even after properly making up the connections?

When I do nitrogen or argon, which is rarely, I use my regular gauges, an adapter to my welding gas regulator, and coat all fittings with Big Blue or Pink, whatever gives a good skin and makes long lasting bubbles. I've only ever had one leak, and that was 35 years ago. Neither my first rodeo or my last.

 

[fitter30]

Pressure test thowing a little gas in a system 500 lb is to check for very small leaks. New install just checking lines and evap. Leaks even a oz a month are hard to find. All the units today are critical charge that if they lose a 1 or 2 oz they stop cooling or heating correctly. There is very little wiggle room either being over or under charge. The days of adding gas on the fly is over especially with variable refrigerate flow equipment.