OMM 1008-1
7
SP
Setpoint
Suction Superheat
Suction superheat is calculated for each circuit using the following equation:
Suction Superheat = Suction Temperature – Evaporator Saturated Temperature
Stageup/Stagedown Delta-T
Staging is the act of starting or stopping a compressor or fan when another is still operating. Startup and Stop
is the act of starting the first compressor or fan and stopping the last compressor or fan. The Delta-T is the
“dead band” on either side the setpoint in which no action is taken.
Stage Up Delay
The time delay from the start of the first compressor to the start of the second.
Startup Delta-T
Number of degrees above the LWT setpoint required to start the first compressor.
Stop Delta-T
Number of degrees below the LWT setpoint required for the last compressor to stop.
VDC
Volts, Direct Current; sometimes noted as vdc.
VFD
Variable Frequency Drive, a device located on the compressor used to vary the compressor speed.
