Dunkirk Error E52: Return water sensor open
Blocking (auto-reset) error: the return water temperature sensor reads open circuit. The control holds off and returns to standby when a valid return temperature is read. Display shows 'E52 Return Sens Open'. We diagnose and repair it across Greater Vancouver — same-day and after-hours.
Blocking (auto-reset) error: the return water temperature sensor reads open circuit. The control holds off and returns to standby when a valid return temperature is read. Display shows 'E52 Return Sens Open'.
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 E52
- Return sensor harness unplugged (at sensor or control J5)
- Broken sensor wiring (loss of continuity on the brown wires)
- Failed return water sensor (out-of-range/open)
- Corroded connector
What you can safely check
- No homeowner-safe internal checks - have a technician verify the return sensor and J5 wiring against the resistance 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 E52
Genuine Dunkirk parts we supply and professionally install — never for DIY.
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Dunkirk Error E52 Repair Across Metro Vancouver
Frequently Asked Questions
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