WhitePointBeach said:For everybody who hates the noise level from the Merrimack, my experiments with noise reduction should begin within a week or so. I ordered the acoustic dampening material that I need and it should arrive today. Then I will wait for an oppotunistic day to let my stove cool down (it is burning full time) and then I will dissassemble the blower assembly and rebuild it with the sound dampening material in place. I would love to get 15-25dB-A reduction. At that level, you would only hear wind noise at speeds up to 50% or so and then above that the mechanical/electrical noises should be really minimal.
If this approach yields inadequate nosie dampening, I will go to plan B which is a complete redesign of the blower assembly. This is a much more ambitious project. I plan to use axial flow fans instead of the centrifugal blower that is currently used. Axial fans (like those used in computers for cooling) are MUCH quieter than centrifugal blowers. The tradeoff seems to be pressure output, but I am not sure that would be a factor in this application given the reasonable or low backpressure that should be created by the iron heat exchanger. If anyone out there is a more experiences mechanic engineer who works with HVAC blowers or cooling fan design, please contact me and we could work on this together. I am a bit out of my element as I am an electrical engineer.
I will update you with the results of my experimentation.
WhitePointBeach said:Mica,
Here are 2 photos of the wiring in my Merrimack. The first shot "Merrimack Wiring" shows the view through the right side (when viewed from the front) little magnetic access door. You can see the wire going from the blower on the left toward the hole on the right. The 2nd photo "Merrimack Wiring 2" shows an interior shot of the wire passing through the sheet metal hole with the rubber bushing in place.
Unfortunately, I was not willing to go through the trouble of removing the cast iron surround so I could shoot a photo of the outside of the sheet metal on the right side so you could see the actual hole the wire comes out of. That is a pretty big project and it took me quite a bit of tinkering to get the surround on perfect with the insert pushed back flush against it. I am not willing to wrestle the 480lbs beast again.
No it was not easy to get these photographs, thank Motorola for making the Droid so small and with such a nice flash and macro camera.
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