Navien NPE-240A Service Manual

Troubleshooting 101
5.1.13 432Error
Error occurrence conditions and check items
Error Description
E432
Cold Water water
temperature sensor
open
If an error (open: 14°F(-10°C) or lower) in the cold water temperature sensor is detected, the system displays the
432E (cleared automatically) error message on the front panel. The water heater initiates shutdown mode.
Check items
1. Check if the cold water temperature sensor is open and if the connector is attached properly.
2. Check the defect of the cold water temperature sensor.
3. Defective PCB
Before measuring resistance of the thermistor,
detach the connector from the PCB.
Check connector
( #5 and #6 of CON 7)
(see page 52 for Wiring Diagram)
Replace the secondary heat
exchanger inlet thermistor
Resistance between #5 and #6 of CON 7 is from
0.437k to 176k at normal conditions.
NO
Is the secondary
heat exchanger inlet
thermistor normal?
Yes

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