Navien NR-180 Installation Manual page 77

Navien Gas Water Heater Installation
█ Service
GENERAL TROUBLESHOOTING
PROBLEM POSSIBLE SOLUTIONS
It takes a long time to get hot water to the fixtures.
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Circulation pump is in freeze protection mode. Circulation pump needs to
change hot water circulation mode.
The water is not hot enough.
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Check ground water temperature first and system setting temperature.
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Check cross plumbing between cold water lines and hot water lines.
How Shut off main cold water supply valve to the water heater, which means no
water supply to the water heater. Open any hot water faucet. If cold water comes
from hot side faucet, there is cross hot and cold water lines somewhere in facility.
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Is the gas supply valve fully open?
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Is the gas line sized properly?
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Is the gas supply pressure enough?
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Is the set temperature too low?
The water is too hot.
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Is the set temperature set too high?
The hot water is not available when a fixture is opened.
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Make sure the unit gets 120V 60Hz power supply?
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Is the gas supply valve fully open?
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Is the water supply valve fully open?
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Is the filter on cold water inlet clean?
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Is the hot water fixture sufficiently open to draw at least 0.5GPM through
the water heater?
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Is the unit frozen?
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Is there enough LPG gas in the tank?
The Hot water turns cold and stays cold.
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Is the flow rate enough to keep the Water Heater running?
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If there is a recirculation system installed, does the recirculation line have
right check valves?
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Is the gas supply valve fully open?
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Is the filter on cold water inlet clean?
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Are the fixtures clean of debris and obstructions?
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Check cross plumbing between cold water lines and hot water lines.
Hot water temperature fluctuating.

Check incoming cold water pressure whether it is too low. (needs Min. 15PSI)

Is the filter on cold water inlet clean?

Is the gas line sized properly?
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Is the supply gas pressure enough?

Check for cross connection between cold water lines and hot water lines.
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