what are- amp draw, refrig line sizes and linear length,(i dont think ive EVER seen a 15ft lineset) indoor coil size, type of metering device? if there was a drier id say it might be installed backwards or you didnt purge with nitrogen as you welded your joints and got some trash on the screen at the metering device. (btw you should really put a drier on it) sorry bud, but not installing a drier kinda screams inexperience to me as well. or as daddo said maybe you stacked metering devices and the piston needs to be removed. when you opened the first service valve on the unit did you notice if the other, still-unopened, valve's gauge pressure came up close to equalized? does the unit pump down when you close the liquid valve? if so, does it pump down quickly? you would think a 2.5t system with 15ft of line would pump down in a jiffy. did you use rigid copper to tie the unit in? if you did, did you take the rubber plug out of the end of it? (stupid question but ive seen an experienced guy in a rush leave the plug in it and melt it as he welded the joints creating a MESS and restriction.) I havent seen it first hand but have heard of moisture freezing up near a txv partially clogging it. 500 micron is prefered, not 250. you may not have enough refrigerant in the system. "116in of refrigerant"? is that some kind of metric system im not aware of? do you mean 116oz? who knows, its hard to troubleshoot over the net. keep looking, youll find the problem. either that or call a different tech that CAN be there with you to offer a different perspective.

There is a possibility hot air from the attic or other area is being drawn into the Return Air. It could be entering at a point or area where you are not measuring that temperature increase. Do not Measure the Return Temp where it goes into the Return Air Grille, that will be before the hot air enters the Return. Check Return Air (RA) at grille & at entry of blower for heat gain, due to hot Return Air leaks. Where air-handlers' are set over Return Air Chambers check for air leaks through the sheet rock & down the wall studs from the attic - this is a fairly common condition that will overload the AC system! Compressor amp draw should be real high & condenser discharge air a very high delta t. Compressor will be laboring. Check the compressor discharge line temp too. I used to run in to this problem far too frequently. Linked page could be relevant: You have to read the entire linked page to understand, what happens too often, when a home is very hot & a geek is charging for a beer can cold suction line! - udarrell Here is a link that might be useful: AC System - Excessive Airflow - Excessive Charge

Likly yes. If everything is normal,such as correct btu for space size,insulation,window size or more spicificly, heat load. And,,,,,unit is operating as desighned to. And,,,,,,enough time has been alowed for unit to stablize operation. It should also be pointed out that a cool suction doesn't assure all is ok either. A unit operating for a long period with insuffecient charge might be iceing or approching. A grossly restricted airflow would make all bets off. Not an all inclusive answer but enough to explain why the methods you mentioned are more indicitive.

Here is a suggestion. See if you can get a fitting that you can attach to the end of the one inch PVC pipe that will allow you to attach a flexible one inch or .75 inch flexible pipe. Then run the flexible pipe around the edge of the condenser pad and secure so it to the ground so it doesn't move. I think running it to the edge of the condenser pad should be fine. Make sure it has enough pitch to drain away from the house. Have the open end visible so you can check it for an dirt accumulation. Perhaps having it rest on brick would help keep it clear. Here is a link for a flexible PVC. I have never used this, but it might work. I know you can buy flexible clear tubing in Home Depot. You just have to find a connector to adapt to the PVC pipe. You want something that has UV protection. Here is a link that might be useful: Flexible PVC pipe