271Error - Navien NHB-055 Service Manual

5.2.14 271Error

Error conditions and Check Items
Error
E271
Temperature differential limit
Check items
Check method
Fault
Space heating pipe
connection
Defective sensor
Possible Issues
Version 1.0
If the temperature differential (supply temperature - return temperature) is higher than
54°F(30°C), the alarm code (E271) is displayed. The system operates normally.
Check if flow rate heating pipe is proper? Check if the heating pipe is clogged with debris.
Check if Air vent is close totally
Check if capacity of the circulation pump(external) is enough to circulate water in pipe
Check if Air Purge is fully done in the system. (If Air Vent is opened?)
Is the space heating pipe
connection normal?
Yes
Check the supply and return
temperature sensor
Possible Causes
1. Check if flow rate heating pipe is proper? Check if the heating pipe is clogged
Abnormal Connection
2. Check if capacity of the circulation pump(external) is enough to circulate water
Defective temperature Check if the temperature sensor is open and if the connector is connected
sensor connector properly.
No Heat Demand User do not use boiler
Description
No
Replace space heating pipe
connection
with debris
in pipe
Check method
NHB Service Manual 111