Navien NP-180 Service Manual page 66

Error
Reason
Code
E021 Cold water inlet: Thermistor 1–open
E022 Cold water inlet: Thermistor 1 -short
Abnormal activity of the
E027
air pressure sensor
Exhaust Overheat: exhaust
high limit switch shuts down
E030 the unit when the flue
temperatures exceed 149°F
(65°C)
E032 Cold water inlet: Thermistor 2 - Open
Abnormal the Water Adjustment
E033
Valve
Abnormal activity of the gas
E034
pressure sensor
E035 Abnormal activity of the gas
pressure sensor
Communication failure
E036
E037 Water Leak Inside unit
E038 Abnormal Circulation PUMP
E039 Abnormal the Flow Sensor
E041 Hot water outlet : Thermistor 2- open
E042 Hot water outlet : Thermistor 2- open
E043 Abnormal cascade connection
E044 Abnormal Thermistors connection
E045 Abnormal the Mixing Valve
Abnormal LP Gas Pressure
E048
©Navien America Inc. 2010
Self-diagnostic / Action
1. Check Thermistor.
2. Check for loose connection
3. Replace Thermistor.
1. Check Thermistor.
2. Check for short or water in connection
3. Replace Thermistor.
1. Check the vent pipe for obstructions.
2. Check and clean the air filter (part #10).
1. Turn OFF the system for at least 30 minutes
then restarts.
2. Clean the inlet water strainer (part #62)
3. Check the water adjustment valve (part #16)
4. Check the heat exchanger; flush with a
cleaning solution
1. Check wire connection at computer board
2. Check wire connection black wire white
connection
3. Check dip switches
4. Loose wire at connection
1. Check to make sure wire connections are
secure
2. Check black and white connection for water
3. Check inlet Thermistor for secure installation
4. Check dip switches
1. Check the water Adjustment valve.
1. Measure gas pressure drop
2. Check hose connection
3. Replace GPS.
1. Contact to Navien tech. dept.
1. Close cold water main.
2. Replace leaking parts.
1. Check the circulation PUMP.
2. Check the Flow sensor.
3. Check the Cold water main.
1. Check the flow sensor.
1. Check the Thermistor.
2. Replace the Thermistor.
1. Check the Thermistor.
2. Replace the Thermistor.
1. Check Model type
(If residential and commercial are installed
together : temperature cannot be above 140°F).
1. Check Thermistors connection.
1. Check the Mixing valve
2. Check mixing valve transformer
1. Check the LP Gas.
2. Fill the LP Gas.
64
NR/NP series service Manual
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Version 2.0