3155 Sensor not kicking on when water is low

[FuzzyZipperbaum]

I have two Tunzie ato's on 2 500g.... love them by the way

However, my unit on one tank no longer recognizes low water and does not kick on. Pump works fine, checked all connections...cleaned it etc.... any suggestions?

thx

 

[rvitko]

About how old is it? Have you tried just soaking the sensor in vinegar for a couple hours to clean any mineral deposits off of it?

 

[FuzzyZipperbaum]

Roger...it is about 2 years ago. I have tried vin but not for 2 hours...will try today. If not what needs to be replaced?

 

[rvitko]

Usually the cause will be a bad optic sensor if it is not just dirty, that is fairly rare though, they usually last nearly a decade but they can get weak or be out of calibration or have a broken wire, in the cable are 4 very fine wires like the wires in a phone cord.