What Er 02 Means
Er 02 is the thermistor code: the thermistor and turbidity module has failed. The module sits in the sump and reports both water temperature and how dirty the water is.
Common Causes of Er 02
- Thermistor/turbidity module failed
- Module connector loose
🔧 One Safe Check You Can Try
Clean the filter and sump in case soil is covering the module, then reset at the breaker.
⚠ Why You Shouldn't Go Further Than That
- The module is mounted in the sump, replaced from underneath.
- Without temperature sensing the heater cannot run properly.
Opening a panel to inspect or repair something yourself doesn't automatically cancel your manufacturer's warranty — but it can risk accidental damage, and some manufacturers do have specific service conditions. Check your product's warranty terms, or ask us, before deciding.