Air conditioner cant keep up and just keeps running!

Hi
Are the filters clean of dust[first thing to check and often forgotten]
There are many faults that affect air conditioners, most are only for trained service techs but you could check out the return air temperature sensor if you can see it. Usually situated on r/h side of indoor unit, it measures the air being drawn from the room back to the unit, if it is covered by dust it can send the wrong info to the control board causing the unit to shut down before desired temp is reached.
Mine started to do this, a strong puff of air from an air bed pump (don't touch the sensor unless you know what you are up to..) fixed it.
You could look at the outdoor unit for ice build up(you don't say of the unit is cooling or heating?) excessive ice
could be a faulty defrost sensor.
[tech job]

What is the model of your air conditioner. With out that information i cant help you with your ac repair problem.

AC Repair Company

the ac cant keep up,you need a bigger ac or a smaller room,if the ac needs to keep cooling,it doesnt have a chance to cycle

If the return line is freezing, as you describe, it typically means that you aren't getting enough air across the expansion coil, causing a large block of ice to build up inside.
Once that happens, you'll always get ice on the return line.
Try cleaning the filter or whatever the AC uses to keep the air clean.

Check the filters and make sure the coils are clean first. Then make sure both fans are running, the evaporator fan and condenser fan. If all of that is ok then you need to get the refrigerant charge checked.

You need to check that tour filters are new. Then check that air is coming from the vents and is at least 15 degrees cooler than room temp. If no air coil is frozen, or blower motor and run cap are not working. If frozen than turn system to off and fan switch is on until you feel air through vents.
You'll need to make sure the outside unit is runing and the larger copper line is cold like a can soda. If it's cold but is freezing up, it needs to have a charge added. If its running but not cold and the fan is not running or the compressor isn't running it could have a blown capacitor. If its not running at all check. the circuit breakers and reset them. And a good idea to keep the outside unit washed with water,and that it is clear of weeds and stuff.

If it runs o.k. at 50, I'd say check thermostat.

If the big pipe out side is cold and sweating and the little one is warm to touch if it is hot to touch under charged. I would suspect insulation, or under sized unit
is their a 20f difference from supply air to return air the i would lean towards insulation. Tom

The problems cold be to small a return air. I do a lot of cool surveys where I check the efficiency of the AC. Some people are putting in Heppa pleated filters and they realy restrict the air flow a great deal. You need at least 1.25 square feet of filter area per ton. 5 ton should have 24 by 36 return. Check to see if coil is dirty. Check air temp. across coil. From return to closest vent. Should be between 18 to 23 degress. Rusty

eventually,cycling process is doing done if the thermostat sense the configure temperayure set up it will trigger to stop your compressor motor as well as the blower fan,blower fan independenly to you compressor.if your thingking that your compressor is tripping off,check your operating current on one line using clamp ammeter and compare to the rated current that tag on
motor compressor body,if the current flow is higher than the rated current specified on compressor motor,well problem occured it will trip your compressor,because overload protector is becoming your thermostat.but if you got same current result it was cycling process.If tripping off maybe air is present in your system call qualified ac tech, to purge out air in system.