Boiler displays E02; often associated with high limit or overheat on some Laars controls.

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

Tripped high limit thermostat, Pump failure or low flow, Air in system, Scale in heat exchanger

Safety first: Allow the boiler to cool. Do not repeatedly reset E02 without addressing the cause.

Verify circulator operation: Ensure the Laars boiler pump is running when there is a call for heat.
Check valves and flow: Confirm all valves are open and there are no obvious restrictions.
Bleed air: Remove air from radiators and high points.
Reset high limit: Press the manual reset button if present after cooling.

When to call a professional: Persistent E02 indicates a serious flow or scaling issue requiring professional service.

Hard 4/5

High Limit Thermostat

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