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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Whirring<br />
Low gas pressure<br />
(whirring)<br />
Exhaust gas flow into the boiler through the air inlet makes<br />
combustion noise.<br />
Check the distance between inlet and outlet (at least 6”).<br />
Check the distance between flues if two or more units are installed<br />
(at least 24”).<br />
Check if there is any obstacle near the flue.<br />
1. Noise occurs due to flame lifting when gas pressure is low.<br />
Check the gas supply pressure (dynamic pressure)<br />
2. Low gas supply due to differential pressure error.<br />
Set DIP S/W 1, 2 to ON (3-stage MIN),<br />
3. Noise due to clogged or damaged gas pressure sensor hose.<br />
4. Check the failure of the gas pressure sensor (output voltage check).<br />
Noise from burner<br />
stage switch<br />
Disassemble the nozzle and check if the hole is narrowed due to<br />
foreign substance.<br />
Set DIP S/W 1, 2 to ON (3-stage MIN), and check the flame.<br />
Compare flame of Burner at combustion section of stages 1, 2 and 3.<br />
Check the nozzle if there is a comparatively unbalanced burner<br />
section.<br />
Noise due to defective air pressure sensor.<br />
Replace the air pressure sensor.<br />
Noise during<br />
combustion<br />
Noise due to torn air pressure hose.<br />
Noise may be intermittent depending on the size of the damage.<br />
©<strong>Navien</strong> America Inc. 2010<br />
125<br />
NR/<strong>NP</strong> series service <strong>Manual</strong><br />
Version 2.0
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