Dunkirk Error E59: Supply sensor shorted / high-temp supply switch
Blocking (auto-reset) error: the supply water temperature sensor reads shorted (near 0 ohm / resistance out of the J5 supply-sensor chart range). Diagnosed via the Supply Water Temperature Sensor Resistance Chart at Control Module J5. Display 'E59 Supply Sensor Shorted'. (Note: the High Temperature Supply Switch at J13-5/6 belongs to the A18 high-temp lockout, not E59.) We diagnose and repair it across Greater Vancouver — same-day and after-hours.
Blocking (auto-reset) error: the supply water temperature sensor reads shorted (near 0 ohm / resistance out of the J5 supply-sensor chart range). Diagnosed via the Supply Water Temperature Sensor Resistance Chart at Control Module J5. Display 'E59 Supply Sensor Shorted'. (Note: the High Temperature Supply Switch at J13-5/6 belongs to the A18 high-temp lockout, not E59.)
Dunkirk fault codes can vary by model and series. Use this as a guide — the same code can have more than one cause. Our Technical Safety BC–licensed technicians read the code, confirm it against your unit's manual, and diagnose the true cause before any repair.
Likely causes of Dunkirk error E59
- Shorted supply temperature sensor / high-temp supply switch element
- Pinched or damaged sensor wiring shorting out
- Moisture/corrosion in the connector
- Failed High Temperature Supply Switch
- Control module input fault
What you can safely check
- No homeowner-safe internal checks - have a technician test the supply switch/sensor resistance against the manual's chart
Beyond these checks, do not open the unit or touch gas/electrical parts — BC law requires a licensed gas fitter. Call us for a proper diagnosis.
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Parts often behind Dunkirk error E59
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Dunkirk Error E59 Repair Across Metro Vancouver
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