16.1 CHARGING UNITS WITH R-410A REFRIGERANT
Charge for all systems should be checked against the Charging Chart inside the
access panel cover.
IMPORTANT: Do not operate the compressor without charge in the system.
Addition of R-410A will raise high-side pressures (liquid, and discharge).
The following method is used for charging systems in the cooling and heating
mode. All steps listed should be performed to insure proper charge has been set.
For measuring pressures, the service valve port on the liquid valve (small valve)
and the service port on the suction line between the reversing valve and compres-
sor are to be used.
CONFIRM ID AIR FLOW & COILS ARE CLEAN
Confirm adequate Indoor supply air flow prior to starting the system. See the
Technical Specification sheet for rated air flow for each ID/OD unit match. Air
filter(s) and coils (indoor & outdoor) are to be clean and free of frost prior to starting
the system. Supply Air flow must be between 375 and 450 cfm per rated cooling ton
prior to adjusting system charge. If a humidification system is installed disengage it
from operating prior to charge adjustment. Refer to the “Checking Airflow” section of
this manual for further instruction.
16.2 MEASUREMENT DEVICE SETUP
Step 1. With an R410A gauge set, attach the high pressure hose to the access
fitting on the liquid line (small) service valve at the OD unit.
Step 2. Attach the low pressure hose to the common suction port connected to the
common suction line between the reversing valve and compressor.
Step 3. Attach a temperature probe within 6” outside of the unit on the copper
liquid line (small line). For more accurate measurements clean the copper
line prior to measurement and use a calibrated clamp on temperature
probe or an insulated surface thermocouple.
39
!
NOTICE
Verify system components are matched according to the outdoor unit
Specification Sheet.
!
NOTICE
The optimum refrigerant charge for any outdoor unit matched with a
CFL/CFM/H*L indoor coil/air handler is affected by the application.
Therefore, charging data has been developed to assist the field technician
in optimizing the charge for all mounting configurations (UF – Upflow, DF –
downflow, LH – Left Hand Discharge, and RH – Right Hand Discharge).
Refer to the charging chart inside the access panel cover on the unit and
choose the appropriate column for the specific application being installed
or serviced. New installations utilizing either a CFL/CFM indoor coil
installed on a gas furnace or an H*L air handler in the downflow or horizon-
tal right hand discharge may require removal of refrigerant since the facto-
ry charge could result in an overcharge condition.
!
CAUTION
R-410A pressures are approximately 60% higher (1.6 times) than R-22 pres-
sures. Use appropriate care when using this refrigerant. Failure to exercise
care may result in equipment damage or personal injury.
!
NOTICE
System maintenance is to be performed by a qualified and certified technician.
