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Flooded systems are supplied with an optional liquid receiver and head pressure control valve.
When the ambient temperature falls during cold weather, the head pressure control valve will
regulate the flow of refrigerant to ensure minimum receiver pressure. The sub-cooling at times
will fluctuate. The condenser is partially flooded with liquid refrigerant in cold weather. In warm
weather the extra refrigerant is stored in the receiver. Therefore, flooded systems require more
refrigerant than fan speed control systems.
•
While charging, if the receiver head pressure is below 320 psi (2206 kPa), block the
condenser coil surface, or turn OFF the fans until pressures rises above 380 psi (2620
kPa) for R-410A, while observe the receiver sight glass.
•
During extremely cold weather all the condenser fans may have to be de-energized to
maintain head pressure.
•
While charging during the summer, meter refrigerant through the suction line until the level
of liquid in the receiver sight glass is approximately 1/3 from the bottom (the leveling ball
in the receiver will start to float) of the sight glass. A liquid charging adapter should be
used to prevent liquid refrigerant from entering the compressor.
•
Measure the superheat at the compressor suction line at least 6 inches (152 mm) away
from the compressor. Compare suction pressure and temperature reading between the
dap4 and the manifolds. If the difference between the manifold reading and dap4 reading
is more than 5%, check for the EEV wiring and any possible alarms on dap4, or EEV
driver. Measure sub-cooling at the liquid line.
•
When charging is complete, add the correct amount of oil, if the line run exceeds longer
than 66 feet (20 m). This procedure must be conducted with the system running at high
load (compressor at full speed). See
APPENDIX: Additional Oil Required (Oz)
amount of oil to add. ALWAYS use clean original Danfoss POE oil 160SZ or equivalent
from new cans.
•
After charging, verifying Subcooling and Oil Level, close the valve on the refrigerant
manifold gauge set and close the service valve on the refrigerant tank and disconnect the
refrigerant manifold gauge set.
5.7.2.1.
Fixed Speed Compressor
•
See
5.7.1.2 Charge Fixed Speed Compressor
for charging the fixed speed compressor
except use the table below for the proper charge conditions.
•
The unit should be allowed to stabilize for 15 to 20 minutes to verify key measurements in
the table below.