Navien Condensing Boiler

[Mike2016]

I have a Navien NHB-110 and recently it gave error code 110 which is a Air pressure switch that activates under vacuum from an inducer pump. Upon inspection I found the hose leading to the switch had ripped. Normally unit will not turn on if this switch is not triggered by vacuum from he inducer motor. However, after restarting the unit and with this hose off, the unit runs just fine, it hsould give an error code as it did the day prior. Would anyone know what would cause it to continue to run bypassing this switch on its own. im thinking its a power board issue. your thoughts are appreciated.

 

[breplum]

when we find an air pressure switch that is suspect, we use the tube and with power off, use an ohmmeter to check see if the switch is working by blowing or sucking.
Normally, the safety system on the main board should prevent operation, (as you already know). So it is very hard to understand why it is behaving incorrectly...unless the pressure switch is stuck closed.

 

[Mike2016]

The switch wiring is fully disconnected, not just the vacuum line. Now it did give an error 110 initially which was the break in the tube, but now it runs without the switch being wired. It should give an immediate 110 error again and not allow the unit to run.