Navien Water Heater NFB-399C

Check the condition and attachment of the ground wire to the boiler casing

Measure ground continuity using a continuity meter

Is the ground continuity satisfactory?

Replace ground wires if ground continuity is not satisfactory

Inspect all water and gas piping for leaks

Are all inspected pipes leak free?

Look for signs of leaking lines

Describe any problems found with the piping

Is the system free of leaks after corrections?

Verify all system components are correctly installed and operational

Enter the cold fill pressure for the system

Is the cold fill pressure at least 12 psi?

Enter the system pressure as the boiler heats up

Is the pressure rise within acceptable limits?

Does the system contain glycol?

Describe the glycol concentration test results

Place a bucket under the boiler to collect the residual water inside the boiler.

Disconnect the power cord to turn off the boiler.

Close the water supply valve and the return valves on the manifold system.

Remove the drain valve on the manifold system to drain the boiler.

Ensure the pump does not become wet during the draining process.

Remove the ignition and flame detector electrodes from the boiler heat exchanger

Electrode Cleaning or Replacement

Remove any deposits accumulated on the ignition/flame detector electrode

Were the electrodes cleaned satisfactorily?

Replace with new electrodes if cleaning was unsatisfactory

Replace ignition/flame detector electrode

Ensure the following conditions are met for the gasket