High Lockout
H3 on Ideal HP290

Your heat pump has detected a problem with a temperature sensor inside the unit, causing the system to stop working to prevent any damage.

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

Plate Heat Exchanger Inlet Refrigerant Thermistor (T2B) Error

What causes this fault?

This fault occurs when the system loses its ability to accurately measure the temperature of the refrigerant as it enters the heat exchanger. This usually happens because the internal sensor has developed an electrical fault or the wiring has become loose or damaged, preventing the main control board from monitoring the unit's safety and efficiency.

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.

Find a Gas Safe engineer
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Related fault codes

H2View →H4View →

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