The fairland air con runs for 20minits and stops, compressor is very hot.What is the low & hi side pressure HELP Please !!!

SOURCE: carrier multi hi wall split a/c

I don't have a diagram, but maybe I can help you. You have 2 compressors, o.k. 2 stage system. A single phase contactor? do you mean a single pole, one side breaks, the other is always hot? Speaking of phases, is this a commercial unit with 3 phase? Also, Each compressor needs a separate contactor to carry the load. What is the question?

SOURCE: Only blows hot air inside

Set thr thermostat to AC instead of HEAT.

SOURCE: air condition not cooling

If this is a heat pump it sounds like the reversing valve is stuck in the heat mode, replacing it requires opening the sealed system, which needs to be done by a licensed ac repairman.

SOURCE: wiring diagram needed for carrier air con unit

Here ya go:
http://www.xpedio.carrier.com/idc/groups/public/documents/techlit/38ckc-c2w.pdf

SOURCE: 24ABR348A0031010 compressor starts then stops.

Hello RR Hard start can't hurt BUT dosen't sound like the problem.Do you have a scroll compressor?They don't need a kit.Does it start every time?It could be short cycling on LOW PRESSURE SWITCH.If the unit is (pumping down) during the run time you have a restriction in the system.Make sure the service valves are open ,do you have a filter dryer colgging up or a bad TXV valve also could cause short run times.20-30 PSI the switch cuts out.