Basic Troubleshooting And Frequently Asked Questions - Navien NR-21DU Manual

Basic Troubleshooting and Frequently Asked Questions

If you experience a problem with the water heater, refer to the following chart for
possible remedies. Error codes that appear on the front panel display are explained in
the following section.
For minor problems, resetting the water heater may resolve the issue. To reset the
water heater, press the Reset button on the front panel.
If resetting the water heater and attempting the remedies suggested in the following
do not resolve the problem, contact an authorized technician, a licensed professional,
or Navien Technical Support at 1-800-519-8794 for service instructions.
Problem
No water comes out
when the hot water tap is
opened.
It takes too long for hot
water to reach the xtures.
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Possible Cause(s)
Is the cold water inlet lter clean?
Is an error code displayed on the
front panel?
Is the water heater frozen?
Are you using the external
recirculation mode?
What to do
Ensure that the shut–o valves on the
hot and cold pipes are open.
If an error code is displayed, refer to the
Error Code Guide.
Have a contractor install a recirculation
return line from the furthest faucet back to
the water heater.