Navien NPE-180A Service Manual page 79

Check method
Failure mode
Ignition failure
78 NPE Service Manual
Cause
1. Check if the main gas valve is open.
2. Check the gas supply pressure.
NG: 3.5" - 10.5" W.C, LP: 8" - 13" W.C
●
LP pressure drop occurs frequently in the winter.
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3. Check the flexible pipe diameter for compatibility with the water heater.
4. While the static pressure is normal, the use of another gas appliance may cause
a possible drop in gas pressure to the unit. Therefore, it is required to check the
dynamic pressure.
Static pressure: Gas pressure during stand by.
Gas supply error ●
Dynamic pressure: Gas pressure at max combustion. (2nd stage MAX combustion
●
setting: DIP S/W 1-1 ON)
5. If a CSST connector has been used, check to ensure that it is not been overtightened
resulting in the seal obstructing gas flow.
6. Check the meter class (Example)
Gas meter Water heater Furnace
●
425 CFH (Gas Meter) ≥ 195 CFH (Water Heater)+ 58.8 CFH (Furnace)
●
 1 CFH = 1,020 Btuh
Digital pressure
manometer
Check gas supply pressure(Refer to page 24)
Defective electrode gap and shape disables ignition.
Appropriate electrode gap: approx. 3~4mm(1/8") (replace if defective)
●
Defective electrode
An ignition fail may occur due to improper gap, while discharge seems normal when
●
gap and shape
checked via the flame monitoring window. Therefore, it is required to check the gap
after disassembly.
Check method
Domestic gas stove
+ 63.7 CFH (Domestic gas stove)
A shifted seal narrows the inner diameter of CSST
connector
Version 2.21