Dynamic Hum, Dynamic Hum,

[tiger]

Where's this dynamic comin' from?

Sometimes the Accentra insert makes a noticeable hum; I watched the indicator lights looking for a pattern, like if it was only when the feed motor light was on. Nope.

But if I push on the insert, towards the fireplace horizontally, not much pressure at all, and it goes away. Even pressing on the decorative surround plate between the insert and the fireplace helps. Is there a fix? I noticed when the tech had it out for a cleaning, they barely got the latches closed, I do not foresee making those tighter.

 

[rona]

The exh fan on Harman products are on a very long time and is the only thing that is constantly on. Being a moving part it can produce noise or a slight vibration which can be transferred. We had that problem on a PC45 and it went away if I removed the covering or shields in back of the stove. Metal on metal transferred the noise. Maybe moving the shields a little bit and tightening the screws would help you.

 

[Peterfield]

Where's this dynamic comin' from?

Sometimes the Accentra insert makes a noticeable hum; I watched the indicator lights looking for a pattern, like if it was only when the feed motor light was on. Nope.

But if I push on the insert, towards the fireplace horizontally, not much pressure at all, and it goes away. Even pressing on the decorative surround plate between the insert and the fireplace helps. Is there a fix? I noticed when the tech had it out for a cleaning, they barely got the latches closed, I do not foresee making those tighter.

Just went through that exact scenario. I first thought maybe something loosened up in the framing. The hum occurred mostly when stove was shutting down but could also occur anytime. After a while, it turned into a rhythmic vibration where every 10-10 seconds it would vibrate and it was driving me nuts. Gradually isolated it to a failing combustion/exhaust motor, had it replaced under warranty and no more issue. From your sig, it looks like you are just beyond the 2-year warranty for motors but give your dealer a call anyway and tell them how long it's been going on. Maybe they'll "adjust" the install date and do the work under warranty.

 

[TStark]

I went to great lengths to remove harmonics from my invincible, with good success...

Some things that helped, each individually got me to lower noise levels...and when combined, a remarkably quiet stove.

Hight temp automotive rtv along the seams of the convection blower housing.

Then 1/16" adhesive-backed cork onto the convection blower mounting flange and on flat portions of its fan body.
Then added butyl -backed washers to the fan mounting bolts

Then placed 1/2" silicon rubber under the stove, between the stove base and its bluestone base

A smear of black rtv under each mounting tab for each access panel where metal-to-metal contact occurs, allow to dry before reassembly. Totally hiddden when reassembled.

A similar smear of rtv under your decorative plate where contact occurs, may suppress any buzz.

As Peterfield sez, could also be a failing motor... if it slows to a new rpm, that is near a multiple of another fan's rpm, then there will be a rythmic harmonic that will want to shake things.

 

[tiger]

All good info. I do not hear what would sound like an rpm drop at any time, not sure if that impacts the possibility of a bad motor.

I think I'll live with it until spring, then, when I'll finally succumb to pulling it out for a cleaning by myself, and perhaps I can figure out where all these places to add RTC, etc., are.

 

[Bioburner]

Sometimes is as simple as the room fan having some dirt or bug stuck in the fins.