AAON LL-540 - Manual (Page 32)

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modulates to bypass discharge gas around
the condenser. The discharge gas warms the
liquid in the receiver and raises the pressure
to the valve setting. The following schematic shows an example system using
the LAC valve.
Figure 11 - Piping Schematic of Example System using the LAC Valve.
OROA Valve
This system uses a non-adjustable head
pressure control valve that performs the
function of limiting the flow of liquid
refrigerant from the condenser and at the
same time regulates the flow of the hot gas
around the condenser to the receiver. The
valve setpoint is 180 psig. This valve is
called an OROA valve (Open on Rise of
Outlet pressure). The following schematic
shows an example system using the OROA
valve.