Page 25
B-Refrigerant Charge and Check - Fin/Tube Coil
WARNING-Do not exceed nameplate charge under any
condition.
This unit is factory charged and should require no further
adjustment. If the system requires additional refrigerant,
re
claim the charge,
evacuate the system,
and
add required
nameplate charge.
NOTE - System charging is not recommended below 60
_
F
(15
_
C). In temperatures below 60
_
F (15
_
C),
the charge
must
be weighed into the system.
If weighing facilities are not available, or to check the
charge, use the following procedure:
FIGURE 12
REFRIGERANT STAGES
(BOTH FANS ARE ENERGIZED
WITH A Y1 DEMAND)
INDOOR
COIL
STAGE 1
2
1
INDOOR
COIL
STAGE 2
OUTDOOR
COIL
STAGE 1
OUTDOOR
COIL
STAGE 2
OUTDOOR
FAN 1 (B4)
OUTDOOR
FAN 2 (B5)
IV-CHARGING
WARNING
Refrigerant can be harmful if it is inhaled. Refrigerant
must be used and recovered responsibly.
Failure to follow this warning may result in person
al injury or death.
WARNING-Do not exceed nameplate charge under any
condition.
This unit is factory charged and should require no further
adjustment. If the system requires additional refrigerant,
re
claim the charge,
evacuate the system,
and
add required
nameplate charge.
NOTE - System charging is not recommended below 60
_
F
(15
_
C). In temperatures below 60
_
F (15
_
C),
the charge
must
be weighed into the system.
If weighing facilities are not available, or to check the
charge, use the following procedure:
IMPORTANT - Charge unit in standard cooling mode.
1- Make sure outdoor coil is clean. Attach gauge man
ifolds and fit access panel in place with manifold
tubing routed outside of unit near bottom corner of
panel. Operate unit at full CFM in cooling mode with
economizer disabled until system stabilizes (approx
imately five minutes). Make sure all outdoor air
dampers are closed.
2- Check each system separately with all stages oper
ating. Compare the normal operating pressures
(see tables 4 - 6) to the pressures obtained from the
gauges. Check unit components if there are signifi
cant differences.
3- Measure the outdoor ambient temperature and the suc
tion pressure. Refer to the appropriate circuit charging
curve to determine a target liquid temperature.
Note - Pressures are listed for sea level applications.
4- Use the same thermometer to accurately measure the
liquid temperature (in the outdoor section).
D
If measured liquid temperature is higher than the
target liquid temperature, add refrigerant to the
system.
D
If measured liquid temperature is lower than the
target liquid temperature, recover some refrigerant
from the system.
