AAON CL-230 - Manual (Page 8)

8
INSTALLATION cont.
Piping Schematic of Example system using the ORI/ORD valve.
The pressure setting of the ORI valve determines
how well the system will operate. The proper
setting is a function of the specific system in
which is installed. Generally, the setting should
be equivalent to a condensing temperature of
90°F to 100°F or a receiver pressure equivalent
to a temperature of 80°F to 90°F. This means
that as the ambient temperature falls below 70°F,
the head pressure control valve will begin to
throttle. To adjust the ORI valve, remove the cap
and turn the adjustment screw with the proper
size hex wrench (1/4” for ORI-6 and 5/16” for
ORI-10). A clockwise rotation increases the
valve setting while a counter-clockwise rotation
decreases the setting. To obtain the desired
setting, a pressure gauge should be used at the
compressor discharge service valve so the effects
of any adjustment can be observed. Small
adjustments are recommended in order to allow
the system adequate time to stabilize after each
adjustment.
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.
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