Display shows safety chain / general safety error, unit locked out

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Open safety thermostat on De Dietrich unit, Faulty flue safety device, Loose safety loop wiring, Tripped overheat cut-out

Safety first: Do not bypass any safety devices. They are critical for safe operation.

Step-by-step checks:

Reset accessible safety devices: Some models have manual reset buttons on overheat stats. Press gently to reset after the unit has cooled.
Inspect wiring: Check the continuity of the safety loop wiring where accessible, ensuring all connectors are firmly seated.

When to call a professional: If the safety device continues to trip, a deeper fault (overheating, flue issue) must be diagnosed by a technician.

Hard 4/5

Safety Thermostat Chain

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