Navien NCB300-28K, Руководство по обслуживанию

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Troubleshooting 57
Testing methods
Error type Cause Testing method
Circulation errors
Circulation pump fault
The circulation pump and fan run continuously in the error condition.
1. Check the power supply to the circulation pump (AC 230 V).
2. Replace the PCB if power is not available at the pump.
3-way valve fault
Check that the 3-way valve is operating correctly in DHW mode.
If there is no temperature change in temperature;
●
RED + WHITE (AC 230 V): Heating
●
RED + PURPLE (AC 230 V): Hot water
●
3-way valve is faulty if the voltage is normal.
●
PCB fault is the voltage is not available at the 3-way valve.
Heating strainer is
obstructed
1. Check if the strainer is obstructed by debris.
2. Identify the type of debris caught in the strainer (aluminium, oxidised
steel, etc.) to help identify the cause of the obstruction.
Heating or DHW heat
exchanger is obstructed.
1. Disconnect the inlet and outlet pipes from the main heat exchanger. Blow
air through the heat exchanger to check if the pipes are obstructed.
2. If E001 occurs in DHW, check if the DHW heat exchanger is obstructed.
Valve closed
Check the heating inlet and outlet valves and the heating manifold pipes.
At least one valve on the heating manifold must always be open.
Other faults
Model settings
Sudden temperature increases due to PCB DIP switch setting errors or
exceeding maximum settings.
Model
DIP Switch Settings
3 4
NCB300-28K OFF OFF
NCB300-37K ON OFF
NCB300-41K OFF ON
PCB faults If the error condition remains after checking these items, replace the PCB.