I ran into a post here and it concerns my problem of my A/C not cooling
my home down sufficiently:
I would consider 30F condenser dT to be the upper limit on older low
SEER units, beyond which there is an airflow problem. On the newer
high SEER units, I would draw the line at 25F dT.
The lower limit would depend primarily upon load. I would think it
should be about 15F dT or above.
Here is the list of temps I use for online trouble shooting.
Evap air in temp = 66°F
Evap air out temp = 48°F
SST (saturated suction temp) - Where is this measured and how?
Suction line temp near compressor = 35°F
High side: (I'll get these soon)
Cond air in temp -
Cond air out temp
SCT (saturated condensing temp)
Liquid line temp near condenser
description of my system:
2 Ton Copeland Hermetic Recipricating compressor (inside a 1987 seer 8
1980 Tappan furnace
1953 brick ranch style house, with insulated attic and insulated
basement, about 1100 sq ft
Performed a test yesterday with monitoring temperatures becuase it was
very calm and stable outdoor air temps today
Outdoor air temp was 81 from 1pm to 5pm
Inside air temp started at 76.8°F @1pm
inside air temp ended at 75.2°F @5pm
ATTIC AIR TEMP was over 103°F during all the hours
Every half hour the main floor temp only dropped about .18°F during
Humidity on main floor was 42% at 1pm, and dropped to 38% by 5pm
What would you guys call a low seer unit?
couple more things: the temps that are listed in the quoted text are
from my current setup, I just inserted them thats all. I replaced the
furnace blower motor. The compressor is new (few days)
Basement temp is very close to main floor temp (couple degrees
difference(which I think rules out any bad ducting leaks))
AND when the return air is 72°F, the output air from any room vent is
Are these okay temps? I want my house temps to fall at little higher
rate when the system runs. Like for example, it never shut off in those
5 hours as my target temp was 72°F !!!