Pentair Pool Heater E05 Error Code
Check your model first
The source record does not specify an exact model family.
Match the model on your equipment label to the linked manufacturer documentation. The same code can mean different things across model families.
Quick answer
Open Stack Flue Sensor Stack flue sensor circuit is open. The SFS thermistor is disconnected or has failed with an open-circuit reading. SFS connector loose or corroded in the high-temperature flue environment, broken sensor lead wire, thermistor element failed open.
Severity: high · DIY difficulty: easy
Safety
Stop at the exterior: power-cycle at the disconnect, clean the filter/basket, and check for obvious water-flow blockage. Pool heaters combine gas piping, 240 V wiring, and (on heat pumps) refrigerant — burner, control-board, and sealed-system work requires a licensed technician. If you smell gas, shut the gas valve and leave the area first.
What E05 means
Open Stack Flue Sensor Stack flue sensor circuit is open. The SFS thermistor is disconnected or has failed with an open-circuit reading. SFS connector loose or corroded in the high-temperature flue environment, broken sensor lead wire, thermistor element failed open.
First checks before service
1. One-time fault event (power disturbance or transient sensor reading) common DIY
Check: Power-cycle at the breaker/disconnect (or unplug for CPAP), restore, and run the system while watching for the code.
Fix: If the code does not return after a full run cycle, the fault was transient — monitor, no repair needed.
2. Fault persists after a clean reset occasional pro only
Check: If the code returns immediately or every session, note the conditions (startup, heating, after rain).
Fix: A persisting code points at the component the manual assigns to this code — that repair is technician territory.
Sources
- PoolDial error-code reference (manual-backed) — verified 2026-08-29
- Pentair MasterTemp/Max-E-Therm Heater Installation & User's Guide (Section 5 Troubleshooting) — verified 2026-08-29