Navien NP Condensing Tankless Gas Water Heater - Service Manual

Check method
Error type
Cause
Check method
10E occurs
intermittently
Air supply / exhaust
close program is
changed.
1. If 10E occurs intermittently during ignition or combustion,
compare the stan-dard RPM (o.000) with the current RPM (r.000)
at Min / Max combustion(dip switch 1-1&2). If the current RPM is
near the excessive air pressure condition, check the follows:
Air supply / exhaust
Drainage of condensed water
If the air pressure hose is broken or clogged.
2. Replace the old controller with a new one (change the program).
Air pressure
sensor error
Air pressure
hose error,
venturi clogged
1. The air pressure hose is clogged.
Check if the hose is clogged with water remained from installation.
2. Check if the venturi (burner) hole is clogged with soot or foreign
substance.
Blow air with mouth through the air pressure hose.
3. Check if the air pressure hose is torn.
Increased RPM may cause blowout and noise.
03E can occur due to the same trouble.
Defective heat
exchanger
The air pressure sensor error occurs due to heat leaked from the
heat exchanger.
Check if the error occurs continuously after the air volume sensor is
replaced.
After 5 min from the start of the boiler, put your hand near the air
pressure sensor, and check if you can feel the heat.
Condensed
water drain
error
< Check if the venturi is clogged.> < Defective air pressure hose >
Condensed
water drain
error
Air pressure
error
Condensed water
drain error
Defective blower
Exhaust air is locked out due to condensed water drain error.
Check if the condensed water hose or the siphon is frozen.
Check if the condensed water hose is folded.
Remove bottom of trap and verify it is not plugged
1. Replace the blower if the blower RPM is considerably low.
2. Check the blower rpm displayed on the controller. (r.3203200 rpm)
©Navien America Inc. 2010
86
NR/NP series service Manual
Version 2.0