I just had a 2.5 ton Lennox XC-17 installed with the matching cased-coil. My system has a discharge air temperature sensor and I notice that the discharge air temp is anywhere from around 40 to 50f. Based on the manual I should be shooting for a temperature drop around 15 to 20f by doing both wet and dry bulb tests.
My temperature drop is anywhere from 20 to 30f (sometimes a bit more). This is much higher than the "15f" temp. drop I am supposed to have. I called out the HVAC guys who installed the unit and they weren't much help. They did no temperature readings and only increased the blower speed to 1400CFM. It brought the temperature drop down a bit, but not much. They said that it is working fine.
I don't trust these guys as they didn't even know how to properly setup the iComfort thermostat. I had to read up and do it myself.
My questions are... is 1400CFM too much air to be pushing through a 2.5ton coil? Does anyone have any idea what could be causing such a high temperature drop? Also, as long as the coil isn't freezing, is having such a high temperature drop ok? Will I lose efficiency?
Any help is appreciated. Thank-you!