Goodman furnace GMS845 condenser GSC13024 coil CHPF1824

Duct static is high .2" on return .4" on supply

Piston size is correct

This is the upstairs unit in a 100 year old home in Florida, the upstairs is 800 sq ft exactly with r-11 in the attic and nothing in the walls, balloon framing.

A load calculation indicates the unit should work.

A hack installer did the initial install, the ducts leaked horribly. We sealed them up quite well, even the boots to the ceiling. Static pressure is after duct seal. We have replaced the evap coil, the suction line, which was 5/8 and 75 feet and kinked. Replaced with a 7/8 line. Did that today.

Suction pressure is really high at 95 and liquid at 230. Superheat was 20 degrees with 83 degree indoor dry bulb. Psychrometer is broken - thermometers cannot take heat in truck in Florida too well.

87 degrees outside. 83 at return, 68 at distant supply. Airflow is set on Cool H orange wire which should be 800-900 CFM at the high static pressure. Goodman specs call the orange wire 2 tons of AC. Thermocouple in return plenum does not show we are pulling in attic air.

Why is the suction so high? We have been to this house many times. I did not take it apart to check it today, but in the past the evap coil has been only cold and wet in the bottom half and the top half has been dry and substantially warmer (over 74 according to an infrared thermometer) This cannot be right.

Input is appreciated.