Harman P61A Rattle

[mccabedoug]

I've a Harman P61A that is a few years old. I love it. A few weeks ago it began to get a bit louder. The sound is a rattle or slight ringing sound. Location-wise, it is coming from the rear at the bottom of the stove. There are no loose external parts associated with the noise. The rattle occurs all the time when the Combustion Motor is on. It does not stop/start when either the Feed or Distribution motor(s) starts/stops (I checked that).

Apologies that my description is not that accurate. The noise does not preclude us from using the stove, but every once in a great while it stops, and when it does, you can tell the stove is much louder than it should or used to be. Any thoughts/guesses?

 

[bcb1]

Without seeing it, my guess would be the combustion motor, the motor mounting, or perhaps sheet metal panel(s) or something near the combustion motor that might be rattling from a vibration of the motor.

Can you take off the panels while the combustion motor is running and narrow it down to a specific spot? If you could post a video of the rattle to youtube and post the link here, then you'd have a bunch of potential help with diagnosing.

 

[mascoma]

its not the flapper on the combustion air intake is it? Other than that only rattle I've had was the lower back panels which I removed and left off.

 

[mccabedoug]

Without seeing it, my guess would be the combustion motor, the motor mounting, or perhaps sheet metal panel(s) or something near the combustion motor that might be rattling from a vibration of the motor.

Can you take off the panels while the combustion motor is running and narrow it down to a specific spot? If you could post a video of the rattle to youtube and post the link here, then you'd have a bunch of potential help with diagnosing.

Thanks for the reply. Yeah, I didn't really provide much info. I do not believe that it is either of the two pieces of sheet metal on the back as I held each of them steady and it made no difference. I will remove them this weekend and see if I can get a closer look (and listen) at the back of the stove.

 

[mccabedoug]

I took a very short video and gave it a listen and you really cannot hear the rattle that clearly.

I isolated it to the Combustion Motor. I shut the stove off, cleaned out some of the dust bunnies (actually it was not that bad - just a little lint and a few pellets). I checked the mount screws on the Combustion Motor and they are all tight. With the stove off I could spin the fan blades from the back and I could hear a very faint 'ting-ting-ting' as it spun. When spinning by hand the noise is very faint.

I did notice that as I spun it the fan was not exactly centered (visually). It did not hit the edges but it seemed to be just a hair off center.

From inside the stove I spun the large exhaust fan located behind the ash pan and I heard nothing. No resistance anywhere so there is nothing jammed/caught. The noise is coming from the back.

I then gave the stove a good cleaning and started it back up.

 

[65fl]

If you are still hearing the noise, try a mechanics stethoscope. They really help narrowing down the source of noises and you can pick them up for under $10 at Amazon or Harbor Freight.

 

[lessoil]

We had a rattle awhile back. Took some time to find the cause.
In our case it was the heat shield rattling against the stove.

 

[rickwai]

sounds like one of the aluminum fan blades on the back of the comb. motor is hitting the plastic guard. try taking the plastic grate off the fan and see if it changes

 

[mccabedoug]

sounds like one of the aluminum fan blades on the back of the comb. motor is hitting the plastic guard. try taking the plastic grate off the fan and see if it changes

That was one of my first thoughts. I took off the plastic guard and the rattle is still there. I've confirmed that nothing is hitting anything externally. I've also removed both shields on the back of the stove to no avail.

 

[Lousyweather]

its either the impeller inside the stove (make sure the back side is clean, behind the impeller, inside the stove, and all fins are UNbent), or, failing that, its the external fan on the combustion blower.....one fin is likely bent inward slightly, causing brief contact with the housing.......if its neither, look at replacing the fan......

 

[mccabedoug]

I'll check again this weekend but when I shut the stove off and spun the combustion motor by hand I am 99.9% sure that neither fan blade (larger blade inside stove behind ash pan and smaller blade on the back of the stove) is hitting anything. I am leaning towards a bearing but I'll investigate again this weekend. Thanks for your replies.

 

[heat seeker]

The errant blade may just move enough when hot to start hitting something, something to look for.