High
Sensor on Potterton Envoy 30

Your boiler's temperature sensors are giving conflicting readings, which is causing the system to stop working reliably to prevent overheating.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

What the manual says

Manufacturer manual

Flow or return sensor out of calibration

From this model's manual
Verified against the Potterton/Potterton Envoy 30 installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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All 31 fault codes on the Envoy 30

Seeing a different code? Every code this model can display, in one place.

Blocking ErrorBurner OnC1C2C3Case sensorCase temperatureControl failedDisplay not illuminatedDry fireDry fire sensorFan OverrunFan PurgeFan speedFlame lossFLASHINGFlow sensorGas OnHot Surface IgniterIgnition Pre ChecksLockoutOverheatPump Overrun - Central HeatingPump Overrun - Storage TankReturn sensorSensor FlowSensor Flow or return sensorShorted signalStand-byWiring fault

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