Hawkeye Total to test AirCon

Hi,can I use my Hawkeye total to test my air conditioning,I have just bought the STP recharge kit and want to make sure it's all ok before I top it up,not sure if the fan on the front of the condenser is working.
Is it ok to run the compressor all the time .Have lost the shim off the front plate.
Chris

You can test the fan with hawkeye in the EMS circuit tests... if it's low on gas the compressor should be disabled by the dual pressure switch so it's not supposed to start at all

Thanks for that,i shall try that,just topped the gas up,slight leak on charging port,hope it seals itself.
Chris