The AIRSYS Lead-Lag Controller (ASLLC) has built-in protection to protect the HVAC equipment from shelter power loss.  In the event of a power interruption lasting longer than 0.5s, the ASLLC powers off and engages a compressor delay when it is powered on again. However, if the power interruption is <<0.5s, the ASLLC cannot detect the interruption and the compressor may short cycle. In extreme cases the scroll compressor will operate in reverse.  Although all Copeland scroll compressors used in AIRSYS WPU have built-in self-protection for scroll reversal, it is not recommended to engage self-protection regularly as there is potential risk to long term reliability of the compressors.  

It is recommended that you connect a run signal to the ASLLC from the Automatic Transfer Switch or the generator to prevent the compressor from running for 3 minute after power loss. This feature was added in ASLLC software revision 13B42. The diagram below shows how to complete the wiring.

All wiring must be by performed by professional technicians.


Gen-Run Input Alarm


Note 1: Software Revision can be viewed in C Menu (UE1 and UE2)

Note 2: Generator signal can be changed to N.C. in D Menu (DGT)