The PSA-1 Dual Load Sequencer is designed to even the wear of pumps, compressors, air conditioners, etc. in redundant systems. This manual will use the word load throughout this manual in place of pump, compressor, a/c, etc. The PSA-1 evens the wear on the loads by automatically alternating between the two loads based on running time or on-off cycles. The load that is energized first is referred to as the lead load, and the second load is referred to as the lag load. Pressing the A or B push-button selects the lead load.

The ON/OFF CONTROL input is used to energize a load. When the ON/OFF CONTROL input is closed, the lead load is energized. When the input is opened, the lead load is de-energized.

The PSA-1 monitors the FLOW input to verify operation of the load. When the lead load is energized, the PSA-1-1 will wait a selectable period of time. If after this period of time the FLOW input is not closed, indicating that the lead load is not functioning, the lead load is de-energized and the alarm relay is turned on. This load will no longer be energized and the lag load will become the new lead load.

A closure of the AUX input turns on the AUX OUTPUT relay. The user as required can utilize the AUX output relay.