Navien Combi Boiler: Force minimum or maximum firing (special operations)

Force minimum or maximum firing (special operations) on a Navien combi boiler: Special operations hold the burner at a fixed rate for gas pressure and CO2 checks; they return to normal after 3 hours with no input.

Homeowner with a combi boiler problem? Call (647) 657-2977 or book a service call — licensed technicians across Vaughan and the GTA.

Applies to: NCB-250/150H, NCB-240/130H, NCB-240/110H, NCB-190/080H, NCB-190/060H

How to fix force minimum or maximum firing (special operations): step by step

1. Hold Back and Menu together for 3 seconds and choose 7. Special Operations.
2. Normal returns to normal operation.
3. 1st MIN / 4. 2nd MIN: minimum firing (low-fire CO2 / offset).
4. DHW 1st MAX / 5. DHW 2nd MAX: DHW maximum firing.
5. SH 1st MAX / 7. SH 2nd MAX: SH maximum firing (inlet gas pressure, high-fire CO2).

If the unit shows an error code, look it up: Navien Combi Boiler codes

Models

NCB-190/060HNCB-190/080HNCB-240/110HNCB-240/130HNCB-250/150H