Navien Condensing Water Heater NPE-240S

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 mounting screw from the fan assembly

Remove the fan assembly bracket with the attached intake port

Disconnect the wiring connector from the fan assembly

Remove the 4 screws from the gas valve connection

List any parts replaced during maintenance

CAUTION: Authorized Personnel Only

Ensure only an authorized technician or licensed professional performs this procedure.

Gather necessary items for flushing

Press the Power button on the front panel to turn off the water heater.

Disconnect the power supply to the water heater.

Close the 'C' and 'D' valves on the hot and cold water lines.

Connect one tube to the 'A' valve and place the free end in the bucket.

Connect one of the tubes to the circulation pump outlet and the cold water line at the 'B' valve.

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 pin that secures the condensate drain cap and then remove the cap. Use a bucket to collect the condensate

Detach the condensate piping from the unit

Remove the 3 screws located at the bottom of the unit that are attached to the condensate trap

Loosen the clip that secures the hose to the condensate trap, and then pull off the hose

Turn off the gas supply to the unit

Disconnect the unit from the power supply

Turn off the water supply to the unit

Disconnect the wiring connector at the gas valve

Replace the O-ring where the gas valve assembly attaches to the elbow

Replace the old gas valve with the new part and reattach the elbow and gas pipe to the gas valve

Reconnect the gas valve assembly to the unit using screws

Reattach the gas valve wiring connector