Autopilot Salt system

Check system red light flashes and message saying check/Clean Cell on power level 1&2. putting the system on power level 3 the message changed to Low Amps-cell?. On test pilot the system has 17 V & 3.4 Amp. I have cleaned screen. Cell. And the filter. The cell is in very good condition and only 3 year old. The questions are
1- Why the message changed with power level change?
2- What is the correct volt and amp should be?
And what's power level should the system be on? Considering that the system on 230 volts and the cell is SC-60
Thanks.