Navien E030 (exhaust overheating): what to check

Navien display

E030

“Exhaust overheating (the water heater shuts down when the flue temperature exceeds 149 °F (65 °C)”

NPE-A2, NPE-S2 · NPE-2 User's Information Manual, p. 17
Owner checks, then technician

Quoted as printed: the closing parenthesis is missing in the manual.

What it means

E030 is an NPE-A2 and NPE-S2 code: the heater shuts itself down because the exhaust leaving it is hotter than its limit. The limit is tied to the vent material: a built-in control holds the exhaust temperature to 149°F, and as a result Navien allows venting with Schedule 40 PVC NPE-2 Installation & Operation Manual, p. 53. The remedies in the table are the same two as for E016: clean the cold water inlet filter and flush the heat exchanger NPE-2 User’s Information Manual, p. 17.

Check these first

1. If you have the NR-21DU remote, its manual adds a first step: switch the heater off for at least 30 minutes, then restart it NR-21DU Remote Controller Manual, p. 30. The NPE-2 table does not list this step.
2. Clean the cold water inlet filter NPE-2 User’s Information Manual, p. 13. This means draining the heater first. Switch it off with the Power button, close the gas valve and the cold water supply valve, open the hot water taps, and remove the filter over a bucket pp. 11–12. On A2 models, also remove the recirculation inlet filter and open the pump drain plug pp. 11–12.
3. Rinse the filter or filters under cold running water and scrub with a brush if needed. Refit them and refill the heater by reversing the draining steps p. 13.
4. Flush the heat exchanger, or have a technician do it pp. 12–13. The manual’s method circulates a diluted cleaning solution through the heater with a pump for at least 45 minutes, rinses with fresh water for 5 minutes, and ends with another inlet filter cleaning. Navien names white vinegar or a solution made for tankless heaters NPE-2 Installation & Operation Manual, p. 15.
5. Reset the heater with the Back button NPE-2 User’s Information Manual, p. 10.

Navien describes flushing as “a somewhat complicated procedure” and warns that improper maintenance can void the warranty NPE-2 User’s Information Manual, p. 12.

When to call a licensed technician

• E030 returns after the filter cleaning and flush NPE-2 User’s Information Manual, p. 16.
• The flush itself, if you are unsure of any step. The manual sends you to an authorized technician or licensed professional p. 12.
• Any sign of damage from overheating. Navien says to close the manual gas shut-off valve and keep the heater off until a qualified technician inspects it NPE-2 User’s Information Manual, pp. 5, 9.
• Anything behind the front cover NPE-2 User’s Information Manual, p. 6. A fault in the exhaust thermistor itself has its own code, E047, and the table’s only remedy for it is a call to Navien Technical Support p. 17.

Notes for different models

E030 appears in the NPE-2 table and in the NR-21DU remote manual. The NPN table has no E030 NPN User’s Information Manual, pp. 22–23.

The documents word the limit slightly differently. The NPE-2 user’s table gives 149 °F (65 °C) p. 17, the remote manual gives only 65°C p. 30, and the NPE-2 Installation & Operation Manual gives 149°F on p. 53 and “below 150°F (65°C)” on p. 52.

Related Navien codes

• E016 “Overheating of heat exchanger”
• E047 “Exhaust thermostat: thermistor open or short circuit”
• E760 “Flushing/service alarm”

All Navien codes

Navien is a trademark of its owner. How House Works is not affiliated with or endorsed by Navien.