Pentair Pool Heater E05 Error Code

Updated 2026-08-29 · review status: manual-verified Last verified: 2026-08-29

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: intermediate

Safety

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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.

Causes, ranked

  1. 1. Stack flue sensor failed open circuit common pro-only

    Check:

    Fix:

  2. 2. Wiring continuity fault between stack flue sensor and control board (check J3/J6 connectors) occasional diy-ok

    Check:

    Fix:

Parts & supplies for Pentair Pool Heater: filters, control boards, sensors, and common replacement parts.

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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