Navien CH-180, Service Manual, Page: 81 / 155

79
Check method
Fault
Possible
Causes
Check method
Air presure
hose error,
venturi
clogged
Air presure
sensor
error
1. The air pressure hose is clogged.
Check if the hose is clogged with water remained from
installation.
2. Check if the venturi (burner) hole is clogged with soot or debris.
Blow air with mouth through the air pressure hose.
3. Check if the air pressure hose is torn.
Increased RPM may cause blowout and noise.
03E can occur due to the same trouble.
Does APS* have nominal
operation voltage?
Yes
No
Replace APS
Check Connector
Is there any output voltage
from APS?
Check the voltage between black and red wire of
CN 6: 4.5-5.5VDC
No Replace APS
Check the voltage between black and white wire of
CN 6: 0.3-4.0VDC
Yes
*APS: Air Pressure Sensor
Is there any restriction in
airflow?
No
Remove all the restrictions in airflow
around unit and check the vent pipe
Yes
Replace tube
Check vent and connector
© Navien Ameri c a I n c . 20 1 0 CH series servi c e Manua l Version 1 .0