Abnormal air pressure.
Navien E110 is abnormal air pressure. The chart says to make sure the exhaust pipe is free of obstructions and to clean the intake air filter. Section 4.5 also says a clogged intake filter can stop the heater and show error 110. It is not E016 or E030, which are overheating and name the cold-water inlet filter and a heat-exchanger flush.
Likely causes
- Exhaust pipe obstructed
- Intake air filter clogged
Safe checks for E110
- Look at the exhaust termination outside and clear snow, leaves or debris you can see without taking the vent apart
- Clean the air intake filter the way section 4.5 describes. The manual says to do that every 3 to 4 months, and that a clogged filter can stop the heater and show this code
- Press Back to reset after the filter is back in and the cover is on
Capacitors can hold a charge after the power is off. Safety terms.
When to call a pro
If the exhaust is clear and the intake filter is clean and E110 returns, stop. Vent length, the fan and the pressure circuit are technician work. Call a licensed technician or Navien Technical Support at 1-800-519-8794.
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