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506238−01 06/09
Adding or Removing Refrigerant
This system uses HFC−410A refrigerant which operates at
much higher pressures than HCFC−22. The pre−installed
liquid line filter drier is approved for use with HFC−410A
only. Do not replace it with A component designed for use
with HCFC−22. This unit is NOT approved for use with coils
which use capillary tubes as a refrigerant metering device.
COOLING MODE INDOOR AIRFLOW CHECK
Check airflow using the Delta−T (
D
T)
process using the
illustration in Figure 20.
HEATING MODE INDOOR AIRFLOW CHECK
Blower airflow (CFM) may be calculated by energizing
electric heat and measuring:
S
Temperature rise between the return air and supply air
temperatures at the indoor coil blower unit,
S
Measuring voltage supplied to the unit,
S
Measuring amperage being drawn by the heat unit(s).
Then, apply the measurements taken in following formula
to determine CFM:
CFM =
Amps x Volts x 3.41
1.08 x Temperature rise (F)
CHARGING METHOD
Use either
WEIGH IN
or
SUBCOOLING
to charge or
adjust a charge to a system.
WEIGH IN
1. Check Liquid and suction line pressures
2. Compare unit pressures with Table 3,
Normal Operating Pressures
.
3. Conduct leak check; evacuate as previously outlined.
4. Weigh in the unit nameplate charge plus any charge required for line set differences
over feet.
Liquid Line
Set Diameter
Ounces per 5 feet (g per 1.5 m)
adjust from 15 feet (4.6 m) line set*
3/8" (9.5 mm)
3 ounce per 5’ (85 g per 1.5 m)
NOTE
*If line length is greater than 15 ft. (4.6 m), add this
amount. If line length is less than 15 ft. (4.6 m), subtract this
amount.
Refrigerant Charge per Line Set Length
NOTE
This nameplate is for
illustration purposes only. Go to
actual nameplate on outdoor unit for
charge information.
Figure 21. Using HFC−410A Weigh In Method
