Low Head Pressure

[jonc5553]

I have a home unit with a fixed orfice and it just won't pull temp down in house below 76F and it runs a while trying to do that. Unit is probably 14 years old. Put gauges on it and noticed head pressure running 200PSI. Suction running aabout 68PSI.
So I put some gas in it trying to get head up and watching suction pressure.Got head up to about 230PSI and suction up to about 72PSI. Checked subcooling. Liquid line was 100 degrees. Checked superheat after adding gas and had about 4F superheat. So I did a TSH and should have been about 13F. 76F in house. So I removed some refrig. and got it to 13F. Running now at 69Psi and 230 PSI. But at 85-90F my head pressure should be alot higher than that with R-22 Subcooling only about 5-6F. Even tried another set of gauges thinking maybe I had a gauge problem. Checked split across evap. 14-15F split. Like I said, setting t-stat at 78F it will cycle on and off but if I try any lower setting than that it just runs forever and never pulls down. Temp has been running around 95 F every day. Unit has never done that good of a job, this year or previous years. Have roughly 1200 sq. feet and it is a 2 ton unit.

[mikeref]

The air-conditioner is too small for that area

[joe magee]

Junk it. Buy a high efficiency three ton and be done with this issue.

[dane mccarthy]

Do you know the correct refrigerant charge for the unit? if so reclaim the refrigerant and weight in the correct charge of new refrigerant, if that does not work, Im with Joe.