We just purchased a home that has a Carrier Infinity system. We were in the house yesterday and the thermostat read 80 degrees, although it did not feel quite that warm in the house. I manually set the temp to 74 degrees and even though I could hear the fan running and air blowing, the house did not cool off significantly several hours later. I stuck a dial thermometer in the air vent and it read 72 degrees. Should the temp of the conditioned air been lower? I realize that there are many variables and that no one can give me a definitive answer, but I just wanted to ask what things I can check out before calling an HVAC tech. I do know that I have to change the filter (during the inspection, the inspector told me that, but he was unable to test the ac system because the outdoor temp was low at the time). All other systems in the house have clearly been well maintained and the sellers said that the ac system was working properly last summer.
Any suggestions?

Thanks.