High Efficiency Furnace external vent noise

[bigbird]

Vent noise problem. Just installed a Keeprite high efficience furnace with a concentric vent to the outside. Fan runs continususly with no noticable noise. When the burners light up, there is considerable noise coming from the centre vent pipe. Even though fan speeds up when burners are lit, the noise sounds like burner noise, not fan noise.

Noise is amplified as it bounces off adjacient about 15 ft away. Any suggestions as to how to reduce noise?

[paul52446m]

Vent noise problem. Just installed a Keeprite high efficience furnace with a concentric vent to the outside. Fan runs continususly with no noticable noise. When the burners light up, there is considerable noise coming from the centre vent pipe. Even though fan speeds up when burners are lit, the noise sounds like burner noise, not fan noise.

Noise is amplified as it bounces off adjacient about 15 ft away. Any suggestions as to how to reduce noise?

not familiar with this brand. But read the instruction book real close. Is stacking the right size? Wide sweet ell? Pitched properly back to the furnace? Drains properly so no water build up in the inducer. There were some furnaces made that the make a muffler for to hold down noise. How many ell on the stack and how long of run is the stack? Can you take some pic. of furnace and stacking?
Side wall vent?. Send pic. paulm989@hotmail.com