3-Way Valve; Water Pressure Sensor - Navien NCB-700-2S+/42K Service Manual

6. Remove the flow control valve and sensor.
7. Replace it with the new flow control valve and sensor.
8. Turn on water supply, power supply, and gas supply to the
unit.
9. Carefully open a hot water tap and ensure there are no leaks
at the flow sensor connections.

6.2.11 3-way Valve

1. Turn off the gas supply to the unit.
2. Turn off the 230V power supply to the unit.
3. Turn off the water supply to the unit. Drain all water from
the appliance.
4. Detach the wire connector that connects the 3-way valve.
5. Remove the clip on the back of the 3-way valve.
6. Replace it with the new 3-way valve.
7. Connect the 3-way valve wire housing.
8. Turn on water supply, power supply, and gas supply to the
unit.
112 Replacement of Parts
Figure 20

6.2.12 Water Pressure Sensor

1. Turn off the gas supply to the unit.
2. Turn off the 230V power supply to the unit.
3. Turn off the water supply to the unit. Drain all water from
the appliance.
4. Detach the wire connector the connects the water pressure
sensor.
Figure 21
5. Remove the clip on the WPS valve.
Figure 22
6. Replace with new water pressure sensor.
7. Connect the water pressure senor wire housing.
Always use proper O-rings at the water pressure
Note
valve connection to ensure tight seals.