Navien Boiler Troubleshooting. When the air pressure is too high, then the system shuts down to prevent any further damage being done to your boiler. If you have no heat or hot water, first check the power to the unit itself.
![Navien NCB 240 flame loss (error 12) — Heating Help The Wall](https://i2.wp.com/us.v-cdn.net/5021738/uploads/editor/n0/xryqmedz2a3g.jpg)
First of all, as is the case with many home. Navien is one of the ten largest korean manufacturers, which is competing with. Listed below are all the manuals for navien.