Liquid line is sweating on a R-410 a/c split system is that ok

how hot is it outside??? 20 degree split is usually the norm ,,,,,outside 95 then inside will be 75,,,,,where is the line sweating ,,, it should sweat near outdoor unit

thats a good question? due you mena 410 psi

You have non-condensables in the system. Recover refrigerant, change drier and evacuate through both high and low side.

The small line coming in from the outside unit should be warm to hot and the larger line should be cool and sweating with water forming on it. I am taking for granted that the unit was working if so it sounds as if the unit is low on freon. your inside coil should be sweating a lot from top to bottom if it is only cool or sweating on the bottom but less to nothing up top you are low on freon. When very low the unit will stop working just like a broken valve in the compressor. If it is just a little low it will not cool properly and at night it might even freeze the inside coil up.

Listen the easiest way is to add freon on the low side until the line starts sweating. This is the quickest way to do it. The other way you have to know your wet bulb temp on the low side line the outside temp the inside temp at the intake and the ambient temp outside this is complicated and works no better than the sweat method i described.

the metering device is in the outside unit on mini splits that is why the liquid line sweats. pressure reading depend on load high load high readings i would shoot for arount a 40f suction saturation temp

the "Discharge" line sweating on a mimn split is normal all of the flow metering is done in the outside unit . as to it not cooling well are the filters clean? if they are you more than likely have a leak and need to get is serviced

check freon to low or to high. must be charged liquid 410 tank upside down.

Some units the orifice is in the evapoator, where the liquid line connects to the distributor and some are in the liquid line at the evaporator. The best way to find it, is to run the unit and follow liquid line at the evapoator, the line will be warm on one side entering the orifice and cold and sweating on the other side leaving the orifice.

are you sure it is the liquid line and not the suction line? The small line or the big line. should not have frost on the small line or liquid line. Frost normal on the insulated big line.