Started receiving service error code 120 on a five year old Aquapure cell. Tried acidwash, but still didn't solve the problem (the DC cord looked fine). So I figured I would bite the bullet and purchased a new PLC700 kit with new cell, DC cable, and sensor.
I installed the unit yesterday and it was fine - no service code.
Went and checked it this morning, and the 120 code came back on (the cell is on and shows flow). About 20 minutes later, the service code vanished. About 15-20 minutes later, it came back on again.
I've noticed that it has been doing that all day today - on, off, on, off...