Aps - Navien NCB-700-2S+/42K Service Manual

4.7.7 APS

Item
Function Measures the air pressure entering the burner system.
1. Noises occur during combustion.
Fault 2. Imperfect and/or abnormal gas flame.
3. Incorrect voltage at the APS.
1. The boiler does not operate.
Symptoms
2. Excessive carbon monoxide emissions are generated.
Error codes E110
1. Visual inspection: Check wire connections are secure and inspect for wire damage.
2. Voltage test: Test the voltage meets the specifications shown below.
Diagnostics 3. Check the exhaust duct for obstructions or blockages.
4. Check the condensate trap and drain pipes for obstructions or blockages.
5. Check that hot water temperature is normal.
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Testing/inspection
information
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APS (1): RED - BLACK: DC 5 V
WHITE - BLACK: DC 0.3 to 3.5 V
APS (2): RED – BLACK: DC 5 V
WHITE - YELLOW: DC 0.3 to 3.5 V
Description
System Details 49