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rand4 · Jul 3, 2012, 05:01 PM

Hi everybody, I'm hoping I could get some knowledgeable opinions.

I live in a 2 story duplex (the duplex building is cut in half so both sides have 2 stories), about 1200 sq. ft, living room has a high vaulted ceiling, built in around 1990 to '95 according to the landlord.

The central A/C is able to keep the place comfortable enough: about 79 degrees on a hot 90-95 degree day, and down to about 77 on a milder 80-85 degree day. However, to do this it has to run the entire day without shutting off. Also, even on a cool day of about 70 to 75 degrees, even if I turn the AC down to say 65 (so that it intentionally stays on all day) it won't get below about 74-75 degrees inside.

I've tried closing doors and taping over the vents in 3 of the lesser used rooms, leaving the place at about 1000 sq. ft, but that had no real effect.

I've measured the air coming out of the vents at 64-68 degrees when the air temperature at the indoors intake is 75 degrees (did this on a mild 75-80 degree day after the AC had been running a while).

I don't know if this might help, but the AC unit outside shows model # 590anx018000aaaa

Could this be normal operation, or is it likely that the A/C unit needs maintenance? Should the air flowing out of the vents be a lot colder?

Thanks for any help! If at all possible, I definitely don't want to call my landlord if this is normal operation because he's raised the rent on all his other places nearby and that's likely coming my way if I bug him :)

hvac1000 · Jul 3, 2012, 06:01 PM

Originally Posted by rand4

Hi everybody, I'm hoping I could get some knowledgeable opinions.

I live in a 2 story duplex (the duplex building is cut in half so both sides have 2 stories), about 1200 sq. ft, living room has a high vaulted ceiling, built in around 1990 to '95 according to the landlord.

The central A/C is able to keep the place comfortable enough: about 79 degrees on a hot 90-95 degree day, and down to about 77 on a milder 80-85 degree day. However, to do this it has to run the entire day without shutting off. Also, even on a cool day of about 70 to 75 degrees, even if I turn the AC down to say 65 (so that it intentionally stays on all day) it won't get below about 74-75 degrees inside.

I've tried closing doors and taping over the vents in 3 of the lesser used rooms, leaving the place at about 1000 sq. ft, but that had no real effect.

I've measured the air coming out of the vents at 64-68 degrees when the air temperature at the indoors intake is 75 degrees (did this on a mild 75-80 degree day after the AC had been running a while).

I don't know if this might help, but the AC unit outside shows model # 590anx018000aaaa

Could this be normal operation, or is it likely that the A/C unit needs maintenance? Should the air flowing out of the vents be a lot colder?

Thanks for any help! If at all possible, I definitely don't want to call my landlord if this is normal operation because he's raised the rent on all his other places nearby and that's likely coming my way if I bug him :)

I've measured the air coming out of the vents at 64-68 degrees when the air temperature at the indoors intake is 75 degrees (did this on a mild 75-80 degree day after the AC had been running a while).

There should be about 20 degrees TD (total differential) between the intake air/return air and the discharge air temp from the registers. (the more the better) Sounds like the unit could need to be cleaned outside ans serviced to try to bring it into specs. Good luck.