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How to troubleshoot a Navien tankless water heater?

Alton Alexander
By Alton AlexanderUpdated on September 6th, 2022

Navien water heater troubleshooting can be a challenge, but with a little patience and perseverance, you can figure out what is causing the problem and fix it.

1. Call a Navien-certified technician

The first step would be to contact the Navien-certified technician to discuss the issue you are experiencing. The technician would then be able to provide you with a diagnosis and possible repair options.

2. Check the power supply

1.Turn off the power to the water heater. 2.Check the power supply cord to make sure it is plugged into an outlet and not connected to another appliance. 3.Check the power supply to the water heater for proper voltage. 4.Check the fuses in the electrical box for the water heater. 5.If the power supply is okay, check the water heater for proper water flow. 6.If the water flow is okay, check the water heater for proper gas flow. 7.If the gas flow is okay, check the water heater for proper heat. 8.If the heat is okay, check the water heater for proper insulation. 9.If the insulation is okay, check the water heater for proper controls. 10.If the controls are okay, check the water heater for proper valves.

3. Check the water supply

  1. Check to see if there is water coming out of the faucet. If there is, then the water supply is fine.
  2. If there is no water coming out of the faucet, then check to see if the water is running. If it is not running, then the water supply might be broken.
  3. If the water is not running, then check to see if there is water coming out of the water heater. If there is, then the water might be turned off.
  4. If the water is not coming out of the water heater, then the water supply might be broken. In that case, the water might have to be turned off and the water heater might have to be replaced.

4. Check the water level in the tank and make sure it is above the minimum level

  1. Open the lid of the tank
  2. Look for the water level sensor on the side of the tank
  3. If the water level is below the minimum level, turn the water off to the tank and wait until the water level rises to the minimum level
  4. Turn the water back on to the tank and check the navigation error code
  5. If the navigation error code is not present, then the tank water level is above the minimum level and no action is necessary.

5. Check the gas pressure and make sure it is within the proper range

  1. Turn off the gas at the main valve.
  2. Check the pressure gauge on the tank.
  3. Open the main valve.
  4. Wait until the pressure gauge reads zero.
  5. Close the main valve.
  6. Turn on the gas and check the pressure gauge.
  7. If the pressure is below the required range, check the gas line for leaks. If the gas line is leaky, replace it. If the pressure is within the required range, the problem is with the gauge or the valve.

6. Clean the inlet filter and check for any blockages

  1. Remove the inlet filter by loosening the screws located at the top and bottom of the filter.
  2. Inspect the filter for any blockages. If there are any, use a plunger or a vacuum cleaner to clear the obstruction.
  3. Reinstall the inlet filter by tightening the screws.
  4. Check the engine oil level and replace as necessary.
  5. Start the engine and check for any engine noise or irregularities. If there are any, take the vehicle to a mechanic for further inspection.

7. Check the outlet pipe for any blockages

  1. Turn off the gas and water to the home.
  2. Check all of the gas lines and water lines for any blockages.
  3. Check the outlet pipe for any blockages.
  4. If there are any blockages, fix them.

If the answers above didn't work then you should also try:

  1. Check the gas supply
  2. Check the exhaust
  3. Check the controls
  4. Check the safety devices
  5. Check the igniter and make sure it is sparking..
  6. Check the burner and make sure it is clean.
  7. Check the heat exchanger and clean it if necessary.