brand new a/c not able to cool to 72degrees when 90degrees outsid
We just replaced a freon 3-ton 10-seer A/c and coil with a R410A 3-ton 13-seer a/c and coil. The brand new a/c is unable to cool the house down to 72 degrees when the outside temp is above 90 degrees (most summer days here in the south). Best it can do is 76 degrees and it only cuts off for a few hours at night. Filter is brand new. Outside unit is clean. The company that installed it said it was because we had a few vents closed off. We have had all of them wide open for 4 days now and no change to the problem. One bedroom reaches 80 degrees on these days. We did not change anything at all except the a/c and coil. The vents that were shut off had been shut off for 10 years with no problem. The old a/c could easily reach 72 degrees. What is going on here?