3-Way Valve - Navien NCB-180 Service Manual

4.9.15 3-Way Valve

Part
Function
Failure Event
Effects
Error Code
Diagnostic
Color/Number of wires
74 NCB Service Manual
Diverts the water from the space heating system to the DHW plate heat exchanger and back based on
input from DHW flow sensor and PCB.
1. No hot water in space heating mode.
2. No domestic hot water in DHW mode.
In the case that the temperature of space heating is lower than the set temperature, it blocks the water
flow path for domestic hot water so that heating water can flow through space heating pipes.
E016
1. Visual inspection: check the 3-Way Valve connection wire.
2. Voltage check: Check range of voltage shown below.
Blue-Black : ON AC 97 ~ 138 V, OFF 0 V
※ Confirm voltage as the 3-Way Valve operating
Check Point
Version 1.0