If you are using a 12 VDC power supply to power the LV-1K that is also used to power some other equipment, that may be why you are having trouble.  Try using the power supply that came with the LV-1K to power it instead and that should correct the problem.  I have seen this type of problem before when they were trying to share a 12 volt DC source that was powering an alarm panel with the LV-1K. Connecting our power supply separately corrected the problem.