Jandy Pool Heater FAULT-OPEN WATER SENSOR Error Code

Updated 2026-08-30 · review status: manual-verified · reviewed by MiniSplitDecoder Editorial Team Last verified: 2026-08-30

Check your model first

  • JXi 200
  • JXi 260
  • JXi 400
  • LXi 250
  • LXi 400
  • JXi 200/260/400 & LXi 250/400

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 Water Temperature Sensor Water temperature sensor circuit is open (broken). Disconnected sensor, broken wire, failed temperature sensor. Check sensor wiring continuity. Ensure sensor is connected to PIB. Replace sensor if faulty.

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 FAULT-OPEN WATER SENSOR means

Open Water Temperature Sensor Water temperature sensor circuit is open (broken). Disconnected sensor, broken wire, failed temperature sensor. Check sensor wiring continuity. Ensure sensor is connected to PIB. Replace sensor if faulty.

Code meaning varies by series

  • JXi 200/260/400 & LXi 250/400: FAULT-OPEN WATER SENSOR: water temperature sensor circuit is open - faulty wiring/connection or failed sensor. Heater will not fire.

First checks before service

This page currently documents the safe reset triage. If the code returns, use the linked source manual or a qualified technician for code-specific diagnosis.

  1. 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. 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.

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Sources

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