Boiler displays A18, control panel unresponsive or intermittent, sometimes after power fluctuations

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

Defective main control board, Loose low-voltage connectors, Interference or surge damage, Faulty display/keyboard module

Safety: Isolate power before touching any electronic components.

Power cycle: Turn off the boiler at the main isolator for 30 seconds, then restore power. Observe if the fault clears.
Check connectors: Remove the front panel and carefully reseat all plug-in connectors on the main PCB and display module.
Inspect for damage: Look for burn marks, swollen capacitors, or moisture on the PCB. If present, the board must be replaced.
If A18 persists, a Hoval technician should test the control electronics and replace the PCB or display module as required.

Hard 4/5

Main Control PCB

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