State tankless water heater shows E14; unit may not modulate properly.

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

Faulty fan speed sensor, Damaged blower wiring, Control board tach input failure

Safety: Disconnect power and gas before servicing.

Inspect blower harness: Locate the combustion blower and its multi-pin connector. Check for loose or corroded pins.
Check for obstructions: Ensure the blower wheel is clean and spins freely.
Test tach signal: A technician can monitor the tachometer output from the blower to the control board. If no signal is present with the fan running, replace the blower. If signal is present but E14 persists, suspect the control board.

Hard 4/5

Combustion Blower Assembly

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