8
Charging the Unit in AC mode
If the outdoor temperature is 65 degrees F or higher:
After completing the refrigerant line connections, leak checking the system, and evacuating the indoor section and all line
connections (using proper methods), perform the following steps:
1. Determine the recommended charge addition (if applicable) for the system being installed. This information is in the
unit’s QRD (Quick Reference Data sheet).
2. Calculate the amount of additional refrigerant needed for the line set length of the actual installation. This information
is on the first page of the unit’s QRD (Quick Reference Data sheet).
3. Weigh in the additional charge amounts determined by step 1 and 2 above.
4. Adjust the charge to match the superheat (for fixed orifice systems) or subcooling (for TXV systems). There are three
different resources for doing this:
a.) The chargecalculator.com website. This will walk you through the charging process step by step.
b.) The charging tables on the inside of the outdoor unit’s electrical box cover panel. These tables provide superheat
targets for fixed orifice systems and subcooling targets for TXV systems. The system should be charged so that
the measured superheat/subcooling are within 1 degree F of the target listed in the table.
For fixed orifice systems:
• If your measured superheat at the suction valve is
LESS THAN
the recommended superheat value in the table
then
REMOVE
refrigerant.
• If your measured superheat at the suction valve is
GREATER THAN
the recommended superheat value in the
table then
ADD
refrigerant.
For TXV systems:
• If your measured subcooling at the liquid valve is
LESS THAN
the recommended subcooling value in the table
then
ADD
refrigerant.
• If your measured subcooling at the liquid valve is
GREATER THAN
the recommended subcooling value in the
table then
REMOVE
refrigerant.
c.) The charging tables in the Supplemental Charging Information, can be found online in the literature library. The
tables can also be accessed by scanning the QR code on the unit’s electrical panel. The pressures listed in these
tables are for reference only and are to be used in troubleshooting a system.
The system should be charged to
match the superheat or subcooling targets as previously noted and not to match the system pressures
.
Follow the same procedure described in 4b above.
If the outdoor temperature is below 65 degrees F:
After completing the refrigerant line connections, leak checking the system, and evacuating the indoor section and all line
connections (using proper methods), perform the following steps:
1. Determine the recommended charge addition (if applicable) for the system being installed. This information is in the
unit’s QRD (Quick Reference Data sheet).
2. Calculate the amount of additional refrigerant needed for the line set length of the actual installation. This information
is on the first page of the unit’s QRD (Quick Reference Data sheet).
3. Weigh in the additional charge amounts determined by step 1 and 2 above.
4. Return to the system when the outdoor temperature is 65 degrees F or higher and follow the steps defined in step 4 of
the “If the outdoor temperature is 65 degrees F or higher” section above.
