Annual service checklist - Navien NHB-H

What is going on

Annual start-up and service items for the boiler from the User's Information Manual maintenance schedule.

Likely causes

• Annual maintenance due
• Service notification on the display (default 1820 days / 18200 cycles)

Check in this order

1. Warning: Turn off power (and gas for internal work) before servicing.
2. Clean the condensate trap and refill it with fresh water; check the drain line and neutralizer (replace media below pH 6.0).
3. Check for water, gas, flue and condensate leaks; bubble-test vent joints.
4. Check vent and intake pipes are sealed and terminations clear; clean the air intake filter (clogged filter gives E110).
5. Check cold fill pressure (minimum 6 psi), the expansion tank, air vents and operate the relief valve lever.
6. Remove, clean and refit the igniter and flame rod; check the ground wire continuity.
7. Check wiring, control settings and the burner flame (stable, even); check flame signal.
8. Verify CO2 at low and high fire; flush the heat exchanger if combustion or performance shows it is needed.
9. Test the LWCO and check glycol concentration if used.

More boiler guides

• No space heat - Navien NHB-H / NFB-H
• Relief valve discharging - Navien NHB-H / NFB-H