Water Adjustment Valve - Navien NPE-180A Service Manual

4.11.10 Water Adjustment Valve

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