Navien Condensing Water Heater NPE-210S

Turn off the gas supply to the unit

Turn off the 120V power supply to the unit

Turn off the water supply to the unit and drain all water from the appliance

Remove the 3 screws at the hot water outlet fitting to loosen the 2-way valve

Remove the stainless steel clips from the connections

Disconnect the wiring connector at the 2-way valve

Remove the 3 buffer tank screws and pull out the buffer tank

Turn off the gas supply to the unit

Disconnect the unit from the power supply

Turn off the water supply to the unit

Remove the 4 screws located at the bottom of the unit attached to the gas valve

Remove the 4 screws directly on the bottom of the gas valve to remove the gas pipe

Remove the 4 screws directly from the bottom of the gas valve to remove the elbow

Disconnect the wiring connector at the gas valve

CAUTION: Servicing must be performed by a qualified service agency or gas supplier

List any parts replaced during maintenance

Turn off the gas supply to the unit

Disconnect the unit from the power supply

Turn off the water supply to the unit

Remove the screws near the top and bottom of the PCB

Disconnect all wiring connectors from the PCB

Remove the 2 screws located on the back of the case

Remove the old PCB and replace it with the new part

CAUTION: Servicing must be performed by a qualified service agency or gas supplier

Inspect for general signs of corrosion

Check and adjust the gas/air ratio

Carry out a water leak test in operation