Arrived on site to inspect older trane/Intertherm unit making a noise. Upon arrival the customer explained the noise is only happening intermittently. I was unable to reproduce the issue on todays visit, so I performed a full maintenance on the system. I checked the temperature split, amp draws, coils, electrical connections, capacitors, and refrigerant levels. Found CFM has slight wobble while running. Also found unit to be slightly low on charge. Unit is running on R22 so I built quote for conversion. I highly recommend replacement over repairs due to the age of the system, and the type of refrigerant. No other issues were found at this time. All work is complete