Water Is Not Refilled - Navien NCB-180 Service Manual

Check method
Fault Possible Causes
Water is not Cold water valve is
Refilled closed or frozen
Defective auto feeder
Water is not
refilled
Drain valve open
Water flow over
through the
condensed water
hose.
Defective heat
Frequent 351E
Turn on cold water tap and check if the valve works or is frozen.
1. Check the auto feeder valve filter if water is not refilled.
2. Check the power supply (DC 24V).
valve

3. Replace the PCB if power is not supplied.
<Check if the filter is clogged with debris>
Check the drain valve under the left of the main heat exchanger.
Water leaks through the condensed water hose due to a defective heat exchanger.
exchanger
Frequent water filling can occur due to leakage of pipe. Check the leakage on the
Pipe leaks
pipe connector and distributor.
Check method
Replace the auto feeder valve if power is supplied normally.