18
Menu 1 – Expansion Valve Setup
EXV Control Setup Screen
Figure 26 – EXV Control Screen
Table 10 – EXV Setup Parameters
Menu Item
Description
Default Value
Mode Control
In Auto Mode, the control system
adjusts the valve to maintain
discharge pressure. In manual
mode, the system drives the valve
to a fixed position and holds it
there for service diagnostic
purposes.
AUTO MODE
Minimum
Position
The minimum percent the
expansion valve will go to.
15%
Maximum
Position
The maximum percent the
expansion valve will go to.
100%
Superheat
Setpoint
The valve meters the amount of
refrigerant into the evaporator in
the precise quantity in order to
maintain superheat. The
difference between the saturated
suction temperature and the
suction line temperature is the
superheat. The superheat is
factory set for 10°F and should
never exceed 15°F or go below
4°F. Only a trained refrigeration
service technician should adjust
this valve.
10.0
MOP Mode
Setpoint
(Suction
Pressure
Mode)
The EXV behaves as a high limit
suction pressure regulator when
the suction pressure rises above a
preset suction pressure. The valve
regulates to maintain suction
pressure instead of superheat. The
suction pressure set point is
factory set to allow the
compressor to run at the highest
allowable suction pressure. The
valve control automatically reverts
to superheat control if the suction
pressure falls below the maximum
limit or if the superheat becomes
dangerously low.
140 PSI
Kp
Proportional PID value
20
Ti
Integral PID value
1000