With the unit running, check and record the following:
Record this data on an “operator’s maintenance log” like the one shown in Table 19, p. 59. If the operating pressures indicate a refrigerant shortage, measure the system superheat. For guidelines, refer to the “Compressor Start-Up” section.
Important: Do not release refrigerant to the atmosphere! If adding or removing refrigerant is required, the service technician must comply with all federal, state and local laws. Refer to general service bulletin MSCU-SB-1 (latest edition).
Source: Trane (www.trane.com)