air condisner has been tested past vacaum test the frion put in cools for 30 min. then stops cooling you can turn it off and it will cool again for about 30 min. f250 2001 crewcab diesel

 

With the info given would suspect moisture in the system that is freezing after period of operation.

 

how would you remove the moisture vacaum was pulled for 2 hrs

 

What kind of vacuum reading did you have at the time it was being evacuated?
Also, when it stops cooling does the compressor try to run?
How do we know that the system isn't overcharged?
Are you using a set of A/C gauges. If so , what are your pressure readings?

 

Why was the system tested?

Was it opened for repair?

If the system was opened up, was the accumulator replaced?

If the decatant is saturated, a vacuum will not remove all of the moisture in the system, thus you'll have moisture in the system roaming around when running causing the orifice to freeze up.

As Hanky asked...

Was the proper amount of R-134a added to the system (How much)?

If using gauges, what are your LOW and HIGH side readings with the A/C off and at ambient temperature and readings when the A/C is running along with the actual mbient temperature reading.

 

ac was not opened it would just stop cooling come to find out the compressor would stop working is their a high presser switch that had gone bad their is a switch next to the compressor its on the small line next to back of the comp. can this be jumpered to make the comp. work then replaced thanks for the info.

 

We sincerely would like to help you, but it is difficult when someone tries to take shortcuts and skirt around the questions.
Air conditioning repairs do not have to be difficult, but there are certain procedures that should be followed if you are going to fix it right the first time.
What do you say?

 

all i can say is that a shop checked out the system and all the reading were with the pass range unit works great till you get down the road im asking if a switch could cause the comp. to kick out and not come back on that is as much as i know

 

Yes a switch could cause the compressor to kick out...

Could be a bad LOW pressure switch, HIGH pressure switch, fan relay(s), failing compressor clutch (coil breaking down when hot) or anything else in the system.

Static reading and running readings would help along with the ambient temperature. A "pass range" is a vague statement. The actual gauge readings will tell you if your border line charged, properly charged, over-charged or have a failing compressor.

 

There are some things in the conversation that don't add up.
"Use Common Sense" has laid out the information and let's hope you can follow it as best you can.