Navien NPE-240A Service Manual

System Details 67
4.11.10 Water Adjustment Valve
Part Check Point
Function To control the water flow to maintain steady hot water temperatures.
Failure Event The valve cannot modulate or open/close in CASCADE mode.
Effects
1. Water Adjustment Valve is not operating properly.
2. Abnormal flow detected during normal operation. “E434” displayed.
3. Temperature fluctuations at the hot water outlet.
Error Code E434
Diagnostic
1. Visual inspection: Connection and/or breakage of wires. Clean the Domestic cold water inlet filter.
2. Voltage check: Check range of voltage shown below.
Color/Number
of wires
●
RED-BLACK: DC 12 V
●
WHITE-BLACK Start position: DC 0 V
Any open position: DC 5 V
●
BLUE-BROWN: PULSE
ORANGE-YELLOW
OUT
IN

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