AAON LL-540 - Manual (Page 34)

34
Figure 13 - 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.