Section 14. System Charge Adjustment - Trane 4TTM3018 Installer's Manual

Section 14. System Charge Adjustment

14.1 Charge Adjustment
For Independent Charge Verification, please see Section 16.
This system cannot be appropriately charged by
subcooling. This new charging procedure helps
prevent over charging. It is important to follow
these instructions. You will need to measure the Out-
door Ambient temperature, the Suction Line Pressure
(PSIG), The Liquid Temperature and the Liquid Pres-
sure. You will charge to the Minimum Liquid Tempera-
ture or Maximum Liquid Line Pressure, whichever is
reached first.
STEP 1 - Check the indoor and outdoor ambient
temperatures.
The Outdoor Ambient Temperature should be above
60ºF. If if the Outdoor Ambient temperature is below
60ºF then charge to 60ºF temperature and 115 Suc-
tion Line Pressure (PSIG) on the charging charts.
The unit will be under charged and you will have to
return when charging can be accurately performed.
The Indoor Ambient Temperature must be kept be-
tween 70ºF to 100ºF.
Raise the indoor temperature if needed, one method
of increasing the indoor temperature is to run the
furnace.
Decrease the indoor temperature if needed, If the
Indoor Ambient Temperature is above 100 ºF, oper-
ate the system to decrease the indoor temperature.
STEP 2 - Ensure Sections 7, 8, 9, 10, and 13 have
been completed.
STEP 3 - Stabilize the system.
Operate the system in cooling mode for a minimum
of ten (10) minutes.
Important: Whenever charge is removed or add-
ed, the system must be operated for a minimum
of ten (10) minutes to stabilize before accurate
measurements can be made.
If Suction Line Pressure is below 115 PSIG the sys-
tem may experience fluctuations in pressures and
temperatures due to expansion valve hunting.
16
Manual Charge Assist Hookup
Leave bottle closed until ready to charge
125ºF
100ºF
70ºF
60ºF
Outdoor Temp
10 MIN.
Indoor Temp
18-AC78D1-6