Trane 4TTA7 Series Installer's Manual page 22

STEP 2 - Stabilize the system by operating for a
minimum of 20 minutes.
At startup, or whenever charge is removed or
added, the system must be operated for a mini-
mum of 20 minutes to stabilize before accurate
measurements can be made.
STEP 3 - Check the liquid line temperature and
liquid gage pressure to obtain a minimum of 10º
subcooling in heating mode.
Measured Liquid Line Temp = __________ º F
Liquid Gage Pressure = __________ PSIG
STEP 4 - Add charge if a minimum of 10º sub-
cooling is not obtained with the namplate charge
plus additional charge previously added.
STEP 5 - Return to site for adjustment.
Important: Return in the spring or summer to
accurately charge the system in the cooling
mode with outdoor ambient above 55º F.
22
20 MIN.
18-AC107D1-1A-EN