Upon arrival client stated that unit was cooling fine when we did the maintenance visit on June 30th. Now it’s not cooling at all. Upon inspection we did find a leak on the flare nuts outside. We tightened up the fittings and leak tested, no leak was detected durning final test. We quoted 4lbs of refrigerant. As we added refrigerant back to manufacturer we did notice it was about only 2.5lbs low. We rinsed off condenser coils to ensure cleanliness and to make sure the unit was not suffocating. Unit cooling upon departure. ADD NITROGEN PRESSURE BOOST SINGLE UNIT INDOOR OR OUTDOOR UNIT ONLY MUST BE USED WITH AN NCD LEAK SEARCH REPAIR REFRIGERANT LEAKS CAN CAUSE HIGHER ENERGY COSTS AND DAMAGE TO THE SYSTEM. WE ALWAYS RECOMMEND A LEAK SEARCH WHERE THE LEASK IS NOT VISIBLY EVIDENT.