Checking charge on a Fujitsu mini split,ac charging ductless

[hvac20000]

I hardly come across mini splits. Been doing this for 15 years. Wondering how to check the charge it is a 410A system with 3 circuits. There are 2 larger schrader valves on each circuit. I assume one is the high and low side. Do I have to turn them all down and check each circuit or just one. Any ideas or a link on what to do would be great! It is a 12RLS model specifically a AOU12RLS.

[cuchulain]

the only way to positively be sure of the charge on a residential mini-split is by weight.

[D-Allen]

cuchulain is correct. I just clean em and check air temps.

[Danimal535]

[skippedover]

X-2

[ACFIXR]

[calebwsshc]

does any one know a common delta T? I am seeing about 25-30 across indoor coil. Or does any one know commom running characteristics when in "Test Mode" forced cooling. I have one I have been working on that went out on 'disharge temp sensor' recovered charge and weighed back in proper amount after trying to play around with the charge. Now im seeing that is runs under 95 psi, to 85 psi when its running at full capacity and its 74 inside. Just seems abnormal to me, but I am letting it 'do its thing.' hopefully no more problems will arise. Found that it had 7 oz. Extra r-410a in the system, are that THAT critical??

[mark beiser]

If it is a variable capacity unit, hopefully it has a test or check operation mode that will kick back an error code if it is not happy with the amount of refrigerant it has.
Otherwise there isn't really a way to tell if it is correctly charged.