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Approach Temperatures
Table 6
using the approach method. The difference between
the ambient and liquid temperatures should match
values given in Table 6. Refrigerant must be added to
lower approach temperature and removed to increase
approach temperature. Loss of charge results in low
capacity and efficiency.
5. If the system is low on charge, R410A refrigerant
must be added. Be aware of the R410A refrigerant
cylinder. It will be light maroon colored. Refrigerant
should be added through the suction valve in the
liquid state.
Some R410A cylinders are equipped
with a dip tube which allows liquid to be drawn
from the bottom of the cylinder without turning
the cylinder upside-down. The cylinder will be
marked if it is equipped with a dip tube.
power from the compressor when suction line pressure
drops below factory setting at 40 ± 5 psi.
Filter Drier
A drier is shipped with each SCU14M unit. The drier must
be field installed in the liquid line between the liquid line
service valve and the expansion valve.
This drier must
be installed to ensure a clean, moisture-free system.
A
replacement drier is available through the local distributor.
MAINTENANCE
At the beginning of each cooling season, the system
should be checked as follows:
1. Clean and inspect condenser coil. Coil may be
flushed with a water hose.
2. Condenser fan motor is pre-lubricated and sealed. No
further lubrication is needed.
3. Visually inspect connecting lines and coils for evi-
dence of oil leaks.
4. Check wiring for loose connections.
5. Check for correct voltage at unit (with unit operating).
6. Check amp-draw condenser fan motor.
Unit nameplate _________ Actual _________
NOTE – If owner complains of insufficient cooling, the
unit should be gauged and refrigerant charge
checked. Refer to the
Charging
section on page 10.
Evaporator Coil
1. Clean coil, if necessary.
2. Check connecting lines and coils for evidence of oil
leaks.
3. Check condensate line and clean, if necessary.
OPERATION
Condensing unit and indoor blower cycle on demand from
the room thermostat. When the thermostat blower
switched in moved to the ON position, the indoor blower
operates continuously.
High Pressure Switch
SCU14M units are equipped with a high pressure switch
that is located in the discharge line of the compressor.
The switch (SPST, manual reset, normally closed) re-
moves power from the compressor when discharge
pressure rises above factory setting at 640 ± 10 psi.
Low Pressure Switch
SCU14M units are also equipped with a low pressure
switch that is located in the suction line of the compressor.
The switch (SPST, auto-reset, normally closed) removes
Before performing maintenance operations on
system, turn the electric power to unit OFF at
disconnect switch(es). Unit may have multiple
power supplies. Electrical shock could cause
personal injury or death.
WARNING
