Navien NPE-240A Service Manual

Troubleshooting 89
Check method
Fault Possible Causes Check method
Defective safety device
Defective overheat
controller
Check if the contact point of the overheat controller is defective.
●
Use a multimeter to see if the resistance is normal (0.3) or abnormal (∞).
Overheat controller Check if the overheat controller wire is
disconnected ( Normal 0.3 )
Temperature sensor
error
Defective hot water
output temperature
sensor
1. If the hot water temperature is sensed lower than it actually is due to a defective
sensor, check if the deviation of temperature is large due to a defective
temperature sensor.
●
Check the output temperature displayed on the front panel.
2. Measure the temperature sensor resistance, and determine if the sensor is
defective.

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