Navien NP Condensing Tankless Gas Water Heater - Service Manual
Navien NP Condensing Tankless Gas Water Heater - Service Manual
Navien NP Condensing Tankless Gas Water Heater - Service Manual
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Check method<br />
Error type<br />
Cause<br />
Check method<br />
Flame blowout<br />
and noise<br />
occurs after<br />
ignition<br />
Low gas supply<br />
pressure<br />
1. Check the gas supply pressure.<br />
NG: 5”(6” 180 MODEL) ~10.5” W.C, LP: 8”(9” 180 MODEL)~13.5” W.C<br />
LP pressure drop occurs frequently in the winter.<br />
2. Check the flexible pipe diameter.(3/4”)<br />
3. While the static pressure is normal, a large difference of dynamic<br />
pressure may cause drop of gas pressure. Therefore, it is required to<br />
check the dynamic pressure.<br />
Check the static pressure: <strong>Gas</strong> supply pressure as the boiler is stopped.<br />
Check the dynamic pressure: <strong>Gas</strong> supply pressure at boiler MAX<br />
combustion<br />
4. Check the gas pipe connector.<br />
Excessive force in fastening nuts at installation of gas pipe may move<br />
the packing and block the Teflon sealing, causing a drop of gas<br />
supply pressure.<br />
5. Check the meter class (Example)<br />
<strong>Gas</strong> meter <strong>Water</strong> heater Furnace Domestic gas stove<br />
425 CFH ≥ 195 CFH + 58.8 CFH + 63.7 CFH<br />
* 1 CFH = 1,020 Btuh<br />
Check the PCB DIP S/W capacity setting.<br />
PCB capacity<br />
setting error<br />
Model<br />
NR-180(A)/<strong>NP</strong>-180(A)<br />
Capacity<br />
(Btu/h)<br />
150,000<br />
DIP Switch<br />
5<br />
6<br />
OFF OFF<br />
NR-210(A)/<strong>NP</strong>-210(A)<br />
180,000<br />
ON<br />
OFF<br />
NR-240(A)/<strong>NP</strong>-240(A)<br />
199,000<br />
OFF<br />
ON<br />
Flame blowout<br />
and noise<br />
occurs after<br />
ignition<br />
Differential<br />
gas pressure<br />
adjustment error<br />
3-stage MIN differential gas adjustment error.<br />
Turn the adjusting screw under the main gas valve. ½ turn, and check<br />
the combustion.<br />
Adjust differential pressure with the meter after ignition.<br />
PCB DIP S/W 2,3 ON / Stage 3 MIN main gas valve.<br />
89<br />
©<strong>Navien</strong> America Inc. 2010<br />
NR/<strong>NP</strong> series service <strong>Manual</strong><br />
Version 2.0
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