109Error - Navien NPE-180A Service Manual

5.1.9 109Error

Error occurrence conditions and check items
Error
The system checks the RPM signal after the fan starts to run, and displays the error message 109E (cleared
manually) in the following cases:
1. If the RPM remains low or close to 0, the system determines RPM error, and the water heater switches into
E109
Fan motor RPM error
2. If the RPM signal of low or close to 0, is detected for 3 seconds during combustion, the system stops
1. Check if the fan motor works normally using the component test mode (refer to page 47).
2. Check the power supply to the fan (Black + Red, approx. DC 127~184 V)
3. If RPM is significantly low while the fan works and the power supply is normal, replace the fan motor.
Check items
4. If the fan connector is wet due to any reason including leakage, take corrective action by powering the unit
5. Check for loose connection of white connector that attaches the fan motor to the PCB.
96 NPE Service Manual
Lock-Out (gas valve and ignition transformer locked). (However, the air pressure sensor should be normal.)
combustion, and the water heater switches into Lock-Out. (However, the air volume sensor should be
normal.)
OFF, then drying the components completely before continuing operation.
Does the fan motor
have nominal operation
voltage?
Yes
Is there any voltage from
the fan motor?
Yes
Check fan assembly
Description
NO
Check power and connector
Check the voltage between #3 and #5 CON 11:
127-184V DC (check page 52 for Wiring Diagram)
NO
Check the PCB
Check the voltage between #3 and #7 CON 11:
0-7.5V DC
Version 2.21