27Error - Navien NP-180 Service Manual

5.14. 27Error

Error occurrence conditions and check items.
Error
If an error (open: 0.1±0.1 V or lower / short-circuit: 4.5±0.2 V or higher) in the air
27E
volume sensor is detected continuously for 3 seconds, or if the air volume sensor
Air volume
voltage of 1.20 V is detected before pre-purge, the system displays the error
sensor error
message 27E on the room controller and the PCB.
Check the assembly of the connector of the air volume sensor.
Check items
Check the voltage of the air volume sensor.
During fan motor stop, is the
output voltage of APS normal?
During fan motor operation,
is the output voltage of APS
Replace PCB
©Navien America Inc. 2010
Description
No
Check the voltage between black and white wire of
CN 6: 0.2 - 0.6VDC
Yes
No
normal?
Check the voltage between black and white wire of
CN 6: 1 - 4VDC
Yes
98
NR/NP series service Manual
Replace APS Check Connector
Replace APS
Version 2.0