Navien NPE-240A Service Manual

Troubleshooting 111
Check connector motor resistance
(CON9)
(see page 52 for Wiring Diagram)
Panel Test operation mode
(Mixing valve operation)
Reset the unit
Yes
Is the operation normal?
NO
Check method
Fault Possible Causes Check method
Remote controller /
PCB error
Malfunction of mixing
valve
Defective mixing valve
1. Check the operation of the mixing valve using the Component Test mode (refer to
page 47).
2. If the PCB is defective, the motor keeps operating as the mixing valve is OPEN or
CLOSED, or the valve repeats open/close.
3. Replace the mixing valve for other symptoms.
4. As a temporary measure, you can disassemble the mixing valve, open it manually,
and separate the power cable of the mixing valve.
Water heater works but
error occurs
Defective mixing valve
sensor
1. Open or short-circuit of the flow control valve sensor.
2. Check the connector assembly and wiring state of the mixing valve feedback
sensor.
3. Check the operation of the mixing valve using the Component Test mode (refer to
page 47).

Navien NPE-240A Specifications

General

Type	Tankless
Fuel Type	Natural Gas or Propane
Energy Factor	0.97
Energy Efficiency	97%
Voltage	120V
Ignition Type	Electronic
Maximum Input	199, 900 BTU/h
Water Connection Size	3/4"
Gas Connection Size	3/4"
Warranty	15-year on heat exchangers, 5-year on parts, 1-year on labor
Dimensions	17.3" W x 13.2" D x 27.4" H