Can a dirty tankless air filter cause a startup error?

MGI’s recommendation: Match the exact error to the exact heater before deciding that cleaning the filter solves it. A dirty filter can matter, but a startup code is not permission to bypass a combustion safety control.

If you smell gas, leave the home without using switches or a phone inside. Call the gas supplier from outside, and call the fire department if you cannot reach the supplier. Do not approach the heater to investigate. The manual’s gas warning applies before maintenance decisions. Navien safety instructions Stay outside until the gas utility confirms it is safe to return. Utility gas-return guidance.

For example, Navien’s NPE-180/210/240 A2 and S2 user manual says a dust- or lint-clogged air intake filter can stop operation and display code 110. It also gives a filter-care procedure and a three- to four-month interval for those models. Another brand or model may define a similar-looking code differently. Navien NPE-2 user information manual, air intake filter

Photograph the complete code and model label before resetting anything. Record whether the error occurs on every draw or only at startup, and when filter maintenance last occurred. If you can see an intake or vent obstruction safely from outside, share a photograph. Do not climb, dismantle venting, or put anything into the openings.

Use only the owner-care steps that match the unit and your ability to perform them safely. Some procedures require removing a cover after power isolation. If the correct procedure is unclear, the filter is damaged, or access is difficult, arrange qualified service. Do not run the heater with required parts or covers missing.

Cleaning is only a completed answer if the technician or approved procedure also establishes normal operation. When the code returns, request a diagnosis of the air and exhaust path and the specific fault, rather than repeated resets or a replacement part chosen from the code alone. The service record should name what was inspected, what failed, and how safe operation was confirmed.

While waiting, pause use of the faulting heater and use another safe source of hot water if available. Ask the provider to confirm experience with the exact model, whether the visit includes filter care and fault diagnosis, and which finding would require a separate repair.