Navien NHB-150 Service Manual

68 NHB Service Manual
Version 1.0
4.9.4 Fan Motor
Part Check Point
Function
Provides combustion air into the burner and purges exhaust flue gas.
Maintains the gas input with a long vent run, the fan operates with APS for ideal combustion.
Failure Event
1. Fan speed failure: the fan RPM is around 0 RPM.
2. The fan assembly screw is loose and/or the fan is disassembled.
3. Disconnected or defective fan connection terminal assembly.
Effects
1. Unstable combustion condition.
2. Unit vibrating and noise.
3. The boiler is not operating properly.
Error Code E109, E110
Diagnostic
1. Visual inspection: check the fan connection wire and/or the fan mounting location.
2. Voltage check: Check range of voltage shown below.
Color / Number of wires
●
Black-Red: DC 127 V ~ 184 V
●
Black-Yellow: DC 15 V
●
Black-Orange: DC 0 ~ 7.5 V
●
Black-White: 0 ~ 6,700 RPM

Navien NHB-150 Specifications

General

Model	NHB-150
Category	Boiler
Maximum Input	150, 000 BTU/h
AFUE	95%
Vent Type	Direct Vent
Fuel Type	Natural Gas or Propane
Min. Input (NG)	15, 000 BTU/h
Min. Input (LP)	15, 000 BTU/h
Voltage	120 V
Water Connection Size	1 inch NPT
Gas Connection Size	3/4 inch NPT
Vent Diameter	3"