Outdoor sensor shorted
The T Outdoor Shorted error code on Dunkirk boilers indicates outdoor sensor shorted.
Dunkirk T Outdoor Shorted means: outdoor sensor shorted. On this component the documented failure modes are the outdoor sensor has failed — short circuit or open circuit, wiring, connector or harness of the outdoor sensor damaged or loose or flue or air intake blocked or restricted. You can safely reset the boiler once — if T Outdoor Shorted returns, do not keep resetting. A qualified heating engineer should diagnose the root cause.
What Does T Outdoor Shorted Mean
The T Outdoor Shorted code is shown by the boiler’s control board when it detects outdoor sensor shorted. The boiler then stops instead of continuing to run in that condition: the code is the appliance reporting a problem, not proof that the boiler is broken.
| What you see on the boiler |
|---|
| The display shows T Outdoor Shorted and the boiler stops until the fault is cleared |
Common Causes
The manufacturer does not publish a cause list for this specific code. The causes below are the failure modes documented for the same component on other boilers, confirmed by the service literature of 13 different manufacturers.
| Cause |
|---|
| The outdoor sensor has failed — short circuit or open circuit |
| Wiring, connector or harness of the outdoor sensor damaged or loose |
| Flue or air intake blocked or restricted |
| Heat exchanger fouled or partially blocked |
Safety Warning
T Outdoor Shorted involves electrical or pressure-related components. Do not attempt repairs without proper qualifications. Ensure the boiler is electrically isolated before any inspection. If you notice water leaks, unusual sounds, or pressure anomalies, contact a qualified heating engineer immediately.
Parts & Prices
Prices shown are indicative. Actual prices and availability vary by region.
How to Fix It
Measure the resistance of the outdoor sensor with a multimeter and compare it against the manufacturer’s resistance-versus-temperature table; replace it if it is open circuit, short circuit or out of range.
Unplug and re-seat the connector of the outdoor sensor, then check the harness for chafing, corroded pins and breaks in continuity.
Inspect the flue and air intake along their whole length, including the outside terminal, and clear any obstruction or debris.
Have the heat exchanger inspected and cleaned; if it is blocked by limescale or sludge the system needs a chemical flush and an inhibitor dose.
Refer to the Dunkirk service documentation for the detailed procedure. Only a qualified engineer should carry out these repairs.
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Affected Models
Dunkirk models that can display fault code T Outdoor Shorted:
| Model Family | Output Range | Frequency |
|---|---|---|
| All Dunkirk models | — | Possible |
Frequently Asked Questions
Measure the resistance of the outdoor sensor with a multimeter and compare it against the manufacturer’s resistance-versus-temperature table; replace it if it is open circuit, short circuit or out of range. According to the technical documentation, this is the first check on the list for T Outdoor Shorted.
T Outdoor Shorted is not classified as a high-severity fault, so the boiler can be reset once. If T Outdoor Shorted comes back, stop resetting: the underlying cause is still there and needs a qualified heating engineer.