Navien CH-180 Service manual - page 60

58

Valve closed

Defective 

heat-ing 

outlet tem-

perature 

sensor

Capacity 

setting

Defective 

PCB

Thudding 

noise 

caused by 

minimum 

flow

Other 

trouble

Check heating inlet/outlet valve and distributor room valve.

    At least one valve of the distributor must be always open.)

Sudden increase of temperature due to PCB DIP S/W model 

setting error or max setting.

If the trouble continues despite the checking of above items, 

replace the PCB. 

The system recognizes the heating water temperature higher than 

it actually is due to a defective sensor.

    Check the heating outlet temperature displayed (            ).

    Check if there is a significant difference between the tempera

    ture displayed and the one actually sensed.

    Remove the heating outlet temperature sensor connector only,    

    connect a good temperature sensor, and determine if the 

    temperature sensor is defective. Refer to the resistance 

    measuring criteria and the method of measurement.

exchanger is clogged>

G

©Navien America Inc. 2010

CH  series service Manual

Version 1.0