High Lockout
9.1.6 on Ideal HP290

Your heat pump has stopped providing hot water because a sensor that monitors the water temperature has developed a fault or is disconnected.

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.

Technical description

DHW Thermistor (T5) Error

What causes this fault?

This fault occurs when the heat pump loses communication with the sensor monitoring the temperature inside your hot water cylinder. The most common reason is that the sensor has failed internally due to wear, or the wiring connecting it to the main control board has become loose or damaged.

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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Related fault codes

9.1.5View →9.1.7View →

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