Iv-Charging - Lennox ZCC Series Unit Information

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 personal
injury or death.
REFRIGERANT CHARGE AND CHECK
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,
reclaim the charge, evacuate the system, and add re-
quired 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
manifolds 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
(approximately five minutes). Make sure all outdoor
air dampers are closed.
2 - Check each system separately with all stages
operating. Compare the normal operating pressures
(see tables 4 - 7) to the pressures obtained from
the gauges. Check unit components if there are
significant differences.
3 - Measure the outdoor ambient temperature and
the suction 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).
• If measured liquid temperature is higher than the
target liquid temperature, add refrigerant to the sys-
tem.
• If measured liquid temperature is lower than the
target liquid temperature, recover some refrigerant
from the system.
5 - Add or remove charge in increments. Allow the
system to stabilize each time refrigerant is added
or removed.
6 - Continue the process until measured liquid
temperature
temperature. Do not go below the target liquid
temperature when adjusting charge. Note that
suction pressure can change as charge is adjusted.
7 - Example ZC 092S Circuit 1: At 95°F outdoor ambient
and a measured suction pressure of 130psig,
the target liquid temperature is 100.5°F. For a
measured liquid temperature of 106°F, add charge
in increments until measured liquid temperature
agrees with the target liquid temperature.
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agrees with the target liquid