High Lockout
E3 on Remeha Quinta Ace 45

Your boiler has shut down because it has detected that there is either not enough water in the system or it has become too hot.

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

High limit or low water protection tripped

What causes this fault?

This fault occurs when the boiler's internal temperature rises too quickly or the system lacks the water pressure needed to move heat away from the burner. The most common reasons are a seized circulation pump that isn't moving the water, or a significant blockage in the pipework causing the unit to overheat rapidly.

This issue is more frequent in autumn when heating systems are switched back on after a summer of inactivity, which can cause the pump to seize.

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

E1View →E2View →E7View →

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