AAON CN-140 - Manual (Page 24)

24
Condenser Flooding
In order to maintain head pressure in the
refrigeration system, liquid refrigerant is
backed up in the condenser to reduce
condenser surface. The following chart
shows the percentage that a condenser must
be flooded in order to function properly at
the given ambient temperature.
Table 2 - Condenser Flooding
PERCENTAGE OF CONDENSER TO BE
FLOODED
Ambient
Temperature
( ° F)
Evaporating Temperature ( ° F)
0 ° 10 ° 20 ° 30 ° 35 ° 40 ° 45 ° 50 °
70 ° 40 24 0 0 0 0 0 0
60 ° 60 47 33 17 26 20 10 4
50 ° 70 60 50 38 45 40 33 28
40 ° 76 68 60 50 56 52 46 42
30 ° 80 73 66 59 64 60 55 51
20 ° 86 77 72 65 69 66 62 59
0 ° 87 83 78 73 76 73 70 68
-20 ° 91 87 82 77 80 79 76 73
During higher ambient temperatures the
entire condenser is required to condense
refrigerant. During these higher ambient
temperatures, a receiver tank is used to
contain the refrigerant that was required to
flood the condenser during low ambient
operation. The receiver must be sized to
contain all of the flooded volume otherwise
there will be high head pressures during
higher ambient conditions.
Electrical
The
single point electrical power
connections are made in the electrical
control compartment.
The microprocessor control furnished with
the unit is supplied with its own power
supply factory wired to the main power of
the condensing unit.
Verify the unit nameplate voltage agrees
with the power supply. Connect power and
control field wiring as shown on the unit
specific wiring diagram provided with the
unit.
Size supply conductors based on the unit
MCA rating. Supply conductors must be
rated a minimum of 167°F (75°C).
Route power and control wiring, separately,
through the utility entry. Do not run power
and signal wires in the same conduit.
Protect the branch circuit in accordance with
code requirements. The unit must be
electrically grounded in accordance with
local codes, or in the absence of local codes,
the
current National Electric Code,
ANSI/NFPA 70 or the current Canadian
Electrical Code CSA C22.1.
Power wiring is to the unit terminal block or
main disconnect. All wiring beyond this
point has been done by the manufacturer and
cannot be modified without effecting the
unit's agency/safety certification.
Electric shock hazard. Before
attempting to perform any installation,
service, or maintenance, shut off all
electrical power to the unit at the
disconnect switches. Unit may have
multiple power supplies. Failure to
disconnect power could result in
dangerous operation, serious injury,
death, or property damage.
WARNING