High Lockout
H0 on Ideal HP290

Your indoor and outdoor units are failing to speak to each other, which has caused your heating system to stop working.

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

No connection Outdoor PCB to Indoor PCB

What causes this fault?

This fault occurs when the data link between your indoor control unit and the outdoor heat pump unit is broken. The most common reason is a loose or damaged connection in the communication wiring, though it can also be caused by a power failure at the outdoor unit or a faulty circuit board preventing messages from being sent.

This fault can sometimes emerge after heavy storms or high winds if debris or moisture has caused a loose connection or damaged the exposed wiring between the units.

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

H1View →H2View →H7View →

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