Troubleshooting guide

32
· High Discharge Pressure Unloading
Setpoints 1&2 – Active in Suction Pressure or
Process Temperature Capacity Control mode.
These setpoints limit the compressor from
loading at high discharge pressure conditions.
They override the Suction Pressure or Process
Temperature Capacity Control setpoints. The
capacity of the compressor will decrease when
the discharge pressure is at or above the ON
set point. When the OFF setpoint is reached,
the compressor will stop from unloading any
further.
· Motor Amp. Load Limit Setpoints 1&2 – This
control limit is the motor full load current draw
and the maximum current draw. This control
limit will only prevent the compressor from
loading and does not shut down the compres-
sor if the maximum current draw setpoint is
exceeded. The actual values entered may
depend on particular circumstances. The
function of the setpoint is as follows:
If the motor is operating at the full load am-
perage (FLA) setting, the compressor is pre-
vented from loading. If the motor amps ex-
ceed the MAX setpoint, the compressor is
forced to unload until the current is at 1.0625
times above the FLA setting. If the motor
being used has a service factor below 1.0625,
use a value for the FLA that is 10% lower
than the MAX value.
Additional Compressor Controls