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II-PLACEMENT AND INSTALLATION
Make sure the unit is installed in accordance with the instal
lation instructions and all applicable codes. See acces
sories section for conditions requiring use of the optional
roof mounting frame (C1CURB10).
III-CHARGING
A-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, 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 at
full load..
1- Make sure outdoor coil is clean. Attach gauge mani
folds and operate unit at full CFM in cooling mode with
economizer disabled until system stabilizes (approxi
mately five minutes). Make sure all outdoor air
dampers are closed.
Mobile service app: RTU Menu>Component Test>Cool
ing>Cooling Stage 3.
2- Check each system separately with all stages operat
ing. Compare the normal operating pressures to the
pressures obtained from the gauges. Check unit com
ponents if there are significant differences.
3- Measure the outdoor ambient temperature and the
suction pressure. Refer to the charging curve to deter
mine 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).
S If measured liquid temperature is higher than the
target liquid temperature, add refrigerant to the
system..
S 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 tempera
ture agrees with the target liquid temperature. Do not
go below the target liquid temperature when adjusting
charge. .Note that suction pressure can change as
charge is adjusted.
7- Example: At 95°F outdoor ambient and a measured
suction pressure of 130psig, the target liquid tempera
ture is 96°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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