Harman XXV fan noise

[Oregun]

Getting a little fan noise. The volume of the noise (low freq.) rises and falls (about 10 sec cycle).
Stove is about 10 years old but only burns about a ton a year.
Any ideas which fan this sounds like?

attached video

 

[gfreek]

Listened to it multiple times, can't make it out. You have two fans, room blower and an exhaust combustion blower....

 

[Oregun]

Vi

Listened to it multiple times, can't make it out. You have two fans, room blower and an exhaust combustion blower....

Video starts at high volume and goes down to a low then right at the end volume goes up again. Will try oiling the exhaust fan today and see if that helps.

 

[StirnPanzer]

I couldn't make anything out either, but I'm about the worst person to ask because I hear little more then "the permanent dial tone".

 

[Oregun]

I took the exhaust fan out and found a slight ticking when turning the blades by hand from the internal blades rubbing on metal cover that covers the exhaust port. Couldn't hear that noise when the motor is running. So I loosened the allen and moved the metal blade farther away from the metal housing plate. Oiled the motor and put everything back together and fired up the stove. The rising/falling droning sound is gone now and it runs very quiet.

 

[rickwai]

Easiest way to see which motor is noisy on a Harman is to first put it in normal start up and listen. That starts comb blower and not dist blower. If quiet then put in test mode. That starts dist blower. If auger motor is suspect, put in normal start up mode once it starts to feed, open the door that shuts auger off. close the door that starts auger back up.

 

[Oregun]

Easiest way to see which motor is noisy on a Harman is to first put it in normal start up and listen. That starts comb blower and not dist blower. If quiet then put in test mode. That starts dist blower. If auger motor is suspect, put in normal start up mode once it starts to feed, open the door that shuts auger off. close the door that starts auger back up.

Thanks for the tip.
I think I add a little oil to each motor shaft/bearing area on my yearly maintenance because when I first turned it on after oiling it was noisy at first and in a couple minutes after the oil got spread around it got very quiet.