Performed ac maintenance in North Highland. Unit is a carrier condenser on back of house. Unit is about 15 years old. Cannot connect low side wont thread on properly. Tested high side pressure and is at 142psi. Checked capacitor and is in range at 49.8UF and should be 50/5UF. Contactor is a little worn and has rusted the screws so cannot get wires out. Coils are very dirty and will wash off with water to help improve efficiency. Clean spider webs off inside and out side aswell as pulled weeds away from unit. Tested unit for proper operation after I maintenanced it.