Boiler shows E12; communication error between display and main control on some Raypak models.

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

Loose communication cable, Damaged display board, Electrical interference, Failed main control board

Safety: Turn OFF power before handling control wiring.

Steps:

Inspect the communication cable between the user interface/display and the main control board. Reseat both ends.
Check for pinched or damaged cable insulation.
Power cycle the boiler to see if communication is restored.

If E12 persists, either the display module or main control board may be defective and should be diagnosed by a Raypak technician.

Hard 4/5

User Interface Board

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