12 Troubleshooting
If resetting the water heater and attempting the remedies suggested below do not resolve the problem, contact Navien Technical
Assistance Service (TAS) or a Gas Safe Registered Engineer.
Problem
Possible Cause(s)
What to do
No water comes out when the hot
water tap is opened.
Ɣ
Is the cold water inlet filter clean?
Ɣ
Is an error code displayed on the front
panel?
Ɣ
Is the water heater frozen?
Ɣ
Ensure that the shut–off valves on the hot
and cold pipes are open.
Ɣ
If an error code is displayed, refer to
“
4.2 Understanding Error Codes
”
on
page 13.
The water from the hot water faucet
is cold or turns cold and stays cold.
Ɣ
Is the cold water inlet filter clean?
Ɣ
Is the hot water faucet open wide enough
draw at least 1.9 litres of water per minute
(LPM) through the water heater?
Ɣ
Is an error code displayed on the front
panel?
Ɣ
If there is an external recirculation system
installed, is there a check valve on the
recirculation return line?
Ɣ
Clean the cold water inlet filter.
Ɣ
Open the hot water faucet completely.
Ɣ
If an error code is displayed, refer to
“
4.2 Understanding Error Codes
”
on
page 13.
It takes too long for hot water to
reach the fixtures.
Are you using the external recirculation mode?
Have a contractor install a recirculation return
line from the furthest faucet back to the
water heater.
The water is not hot enough.
Is the set temperature too low?
Ɣ
Check the water heater’s temperature
setting. Refer to
“
3.2 Adjusting the
W
ater
Temperature
”
on page 10.
Ɣ
Check for cross plumbing between the
cold and hot water lines.
The water is too hot.
Is the set temperature set too high?
Check the water heater’s temperature setting.
See
“
3.2 Adjusting the
W
ater Temperature
”
on page 10.
4.
Troubleshooting
4.1 Solving
B
asic Problems
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.
