DT CX FOUND #3542 AC 1-1, #1542 AC 1-1, ~~~~~ 3542 AC 1-1 & 1542 AC 1-1 DT CX FOUND COOLANT PRESSURE FAULT.  3542 A/c 1-1 & #1542 A/c 1-1 both units found pressure low. Vacuum/charged 7 kg of freon to LP=35 psi, HP=120 psi. No sign of freon leak. Checked both units cut in/out operation - OK. Temp able to achieve 23'C - 24'C. Monitor for 1 hr, pressure did not drop & no fault reoccur.  Sarma/Anand/Kiran 44366