SECOND
After the compressor has started and reached the
The setting of timer “B” is part of the options setpoint routine and the timer cancels any accumulated time if the compressor reloads before the timer cycle has finished.
An important point... This unloaded run time may, or may not, be included in the mandatory 10 minute run time used to cool the motor windings.
When the compressor has completed the settings of both timer “A” and timer “B”, the Intellisys controller stops the compressor and displays “STOPPED IN AUTO RESTART.”
Pressure sensor 4APT continues to monitor the package discharge pressure and sends information to the controller which automatically restarts the compressor when the pressure falls to the
An advantage to this method of automatic start/stop control is allowing the compressor to stop much sooner in certain situations and timer settings, thereby reducing power costs.
Some Examples of Operation
EXAMPLE 1
The operator selects an unloaded run time of 2 minutes in the OPTION routine and starts the compressor. The unit runs loaded for 8 minutes, unloads and then runs unloaded for two more minutes.
The total running time is 10 minutes which satisfies timer “A” plus the unit ran two minutes unloaded which also satisfies timer “B,” therefore, the unit stops automatically.
This example shows how timer “B” can sometimes be included within the timer “A” interval. Think of the two timers as running parallel.
EXAMPLE 2
The operator selects an unloaded run time of 3 minutes in the OPTION routine and starts the compressor. The unit runs loaded for 10 minutes and then unloads.
At this point, timer “A” has been satisfied but timer “B” still wants the compressor to run unloaded 3 more minutes before allowing an automatic stop.
The total run time for this example will be 13 minutes.
Remember.... If the unit reloads before timer “B” finishes
the 3 minute setting, the partial time is canceled and timer “B” must restart the 3 minute cycle when the compressor unloads again.
44