AC low air flow inside
Location Katy TX (it is HOT)
My son has a Rheem F22 unit that is 10 years old. Probably about a 4 ton unit. The house is 10 years old (~1800 sqft) and is well insulated with double pane windows throughout.
He's getting low air flow inside the house and it is taking a LONG time to cool the house down. The low air flow was first noticed about a month ago. I've looked into the blower unit and the fan is running full speed and the fan blades have minimal dust coating.
We have taken the air filters in the ceiling out and removed 6 of the ceiling registers with still no appreciable increase in air flow. Air filters were fairly clean and have recently been replaced. We have examined the attic ducts and found no loose connections and no signs of air loss there.
I have measured several system temperatures and the one that sticks out is the outside suction line temp is showing 48-50 degrees. That seems way low to me. The evaporator coils are not frozen over. The suction line is sweating good just up to the case of the compressor. The compressor case is not sweating. I'm guessing that something is blocking the air flow over the evaporator coils. The only problem is that when the unit is opened we can only see the downstream side of the coils. These are the rectangular type coils (not the "A" frame type).
I have no way to measure the air pressures on either side of the evaporator coils.
Any suggestions? Am I on the right track? (email@example.com)