Navien NCB-24LSWE, Service Manual

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NCB Service Manual 79 Version 1.0
5.2 Error Code List and Actions
Error
Code Sub
Code
Function Diagnosis/Actions
E001 0 Heat exchanger overheat
1. Clean the strainer.
2. Check voltage via PCB at the pump
3. (AC 230 V)
4. Check that the flow rate is correct
5. Check if water is circulating in the
heating lines.
6. Check the heat exchanger and flush
it with cleaning solution if
necessary.
E003
0 Ignition failure
1. Check the main gas supply
2. Check if the manual gas valve is
open.
3. 2. Check if the igniter is sparking.
4. 3. Tighten the ground terminals on
the heat exchanger.
E004
0 False flame detection
1. Ensure that the ground wire is
connected.
2. Check if the igniter is sparking.
E012
0 Flame loss
1. Check if the main gas valve is open
and verify the incoming gas
pressure.
2. Check the intake air filter.
3. Check the ground wire.
4. Check the power supply.
5. Tighten the ground terminals on
the heat exchanger.
6. Adjust the anti-short cycle time.
E016
0
Heat exchanger overheat
1. Turn OFF the boiler, wait at least 30
min, and then restart the boiler.
2. Clean the inlet water filter and
strainer.
3. Check the high limit switch and
PCB.
4. Check the 3-way valve.
5. Check the heat exchanger and flush
it if required.
E030
0
Exhaust overheat: exhaust limit switch stops the boiler
when the flue temperature exceeds 110 °C (230 °F) for more
than 10 min.
1. Turn OFF the boiler, wait at least 30
min, and then restart the boiler.
2. Clean the strainer.
3. Check the heat exchanger and flush
it if required.
E046
2 Heat exchanger thermistor short error
Check the heat exchanger thermistor
connection.
E047
1 Exhaust thermistor open error
Check the exhaust thermistor
connection.
2 Exhaust thermistor short error
E060
1 Dual venturi limit switch error (ON)
Check the dual venturi connection. 2 Dual venturi limit switch error (Closed OFF)
3 Dual venturi limit switch error (Open ON)