Navien NP Condensing Tankless Gas Water Heater - Service Manual

5.27.3. Circuit breaker operation
Error
Cause
Power supply
Check method
The circuit breaker operates immediately as soon as the power cord
is plugged in the receptacle.
Check the sheath of power cord, or if there is short-circuit.
Check the devices in the order of the power transformer and the
PCB.
Defective part
assembly
If the circuit breaker operates after a repairing work, check the wiring
of each part.
Mind the direction when assembling the ignition transformer.
Be careful that wire is not pressed down when assembling the
main gas valve.
Check if the wire is fixed and well adjusted on the main side of the
heat exchanger.
Circuit breaker
operates
Circuit breaker
operates while
the boiler is
running
If circuit breaker operates during the operation of the boiler, check the
order of operation, and replace the concerned part.
e.g., The circuit breaker operates at switchover to burner stage 3 after
ignition.
Replace the 3-stage valve.
Remote controller
power
Check the wire
Check the power supply to the remote controller terminal.
(DC 19 V or higher)
If there is a problem in power supply, check the output voltage
of the PCB, and take the action separately for wiring error and
defective PCB, respectively.
If the power supply is normal, replace the remote controller.
©Navien America Inc. 2010
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NR/NP series service Manual
Version 2.0