Blower Idea - Has anyone done this?

[reed102]

The noise from my insert's blower is most annoying. I have a new England Stove Works woodburning insert and for a low priced insert it does a nice job, but I guess a very noisy blower is the price you pay for a low price. Anyway, I was thinking of running metal duct work to the insert where the blower would normally be and locating the blower (might have to be a different blow or fan) in some type of sound absorbing box close to the insert. Anyone ever done this or is just another of my crazy ideas.

 

[BrotherBart]

I have never done anything like that but I have also never heard a quiet insert blower. At lower speeds not so bad but every one I have ever heard is loud turned up.

 

[pgmr]

Sounds like it would be ugly, but if function is more important than form, you could probably cut the noise somewhat doing that. You might also consider adding a variable speed motor control, instead, if it is a single speed now.

 

[reed102]

Yes, the appearance issue is a problem that I haven't figured out how to solve. It is a variable speed blower and I only turn it all the way up when everyone is in bed.

 

[Corey]

First, isolate where the noise is coming from. If it is a buzz or hum from a loose mounting or metal to metal contact, that might be able to be fixed. If it is the squeal or grinding of a bearing, it may be time for a new fan. If it is just the hum of the fan blades, there is not too much that can be done except re-engineering as you suggest.

If you are willing to go to that trouble, there are options...The guy that I bought my insert from had it rigged so the fan was in his basement and a duct came up through his floor and blew into the insert. A lot of work, but pretty quiet. I did away with his duct, welded up the hole in the side of the insert and cut a new one in the back. I mounted a 12" fan, on fiber isolation mounts, that spins around 850RPM IIRC. This is big enough to move a lot of air, but spins slowly enough that the blades don't sound like a mini turbojet. You can hear the woosh of air...about like a 12" table fan running, so it is not too bad at all.


Corey

 

[MountainStoveGuy]

you dont realy get that much more heat by running it on high, you just get realativly higher air movement and lower air temperture. If you run it on low you get low air movement and high temperture air. Run it on its lowest setting and turn the celing fan on reverse. Try it and see if you like it.

 

[Chuck Pearson]

Besides buying a variable speed controller, I installed some accoustical foam. American Micro Industries has a selection. Make sure that you get heat resistant foam and make sure the temperature where you place it is not too high. If the blower is on the bottom, it is a lot cooler there than above the firebox.

 

[Corey]

you dont realy get that much more heat by running it on high, you just get realativly higher air movement and lower air temperture. If you run it on low you get low air movement and high temperture air. Run it on its lowest setting and turn the celing fan on reverse. Try it and see if you like it.

I don't know if this was a reply directly to me, but I have tried heating with smaller amounts of air and it just doesn't work in my case. With low air flow, the stove room gets nice and hot, and likely looses a ton of heat because the ceiling and exterior walls are hot, but doesn't get much heat in the house. With a lot of moderate temp airflow, the heat can be carried all the way to the other end of the house (bedroom) and the walls stay cooler which has to mean less heat lost outside.

I've added a firebrick baffle to the stove, so the secondary burn kicks in before the gasses ever touch the outside of the stove. Running the fan full speed doesn't seem to stop the secondary burn, at least in this case.

One benifit of having the fan in the back of the insert is that it pulls air over the outside shround and past the masonry of the fireplace before pushing it through the inner shroud and over the firebox. This first pass acts almost like pre-heating and can add 10-15 degrees to the room air before it even see the firebox. Every little bit helps.

Corey

 

[pgmr]

I've added a firebrick baffle to the stove, so the secondary burn kicks in before the gasses ever touch the outside of the stove. Running the fan full speed doesn't seem to stop the secondary burn, at least in this case.
Corey

Can you post some pics of your firebrick baffle or at least describe it?

 

[ertzog]

I've been thinking about doing this, also.... If you took your time and did the ducting close to the rock/brick out of copper sheet, I think it could be passable. the copper should age nicely.

but you would want some pretty thick sheet material.... one log drop and its ruined.

- on my list of "projects".

 

[Gooserider]

Another thing that could be making your noise problem worse is resonant vibration in the ducting and other metal parts of the system. Thin metal can pick up vibrations and amplify them considerably, almost like a loudspeaker. Also any loose fitting joints or other "rattle points" will also cause problems.

Two tests that will help to show if this is part of your problem are to gently rap different parts of the ducting, fan housing, etc. with a plastic screwdriver handle. Anything that gives a clanging or gong like noise is bad, so are rattles around joints. The ideal is to get a "thud" with no resonance to it. Sort of like really soggy green wood.

On computer chassis, I kill a lot of this by covering some of the inside surfaces with "Gutter repair tape" - This is a tape made with a thin layer of fairly soft aluminum that is backed with a thick layer of a synthetic asphalt / rubber adhesive. It is amazing what a difference it makes. I also try to isolate vibrating stuff like fans and drives by rubber mounting them, which keeps them from transferring their noise to the metal resonators. I don't know just what kind of material might be suitable on a stove in terms of heat resistance. I would probably try to rubber mount stuff like fans using high temp auto silicone sealant, and would probably use that to stabilize any rattling joints as well. There are sound deadeners intended for use on auto firewalls, but I don't know if that would give a high enough heat rating.

Another item that can make a difference is fan grills especially close to the fans. On my PC's where they tend to have grills on one or both sides of the "muffin style" cooling fans I remove them on most fans, especially on the exhaust side. If I do use a grill, I make it one of the thing wire type, not not a stamped steel thing. It makes a perceptible difference - air going past an obstruction will whistle....

Gooserider

 

[cogger]

I laughed when I seen this topic about blowers. Laughing at steam engine in my pic. I'll explain:

1) to get blower you need steam

2) to get steam you need a roaring fire to heat water

3) to get a roaring fire you need blower

any thoughts?

 

[Roospike]

I laughed when I seen this topic about blowers. Laughing at steam engine in my pic. I'll explain:

1) to get blower you need steam

2) to get steam you need a roaring fire to heat water

3) to get a roaring fire you need blower

any thoughts?

Change to Diesel engines? ;-) O'wait , there already did that.

 

[Gooserider]

I laughed when I seen this topic about blowers. Laughing at steam engine in my pic. I'll explain:

1) to get blower you need steam

2) to get steam you need a roaring fire to heat water

3) to get a roaring fire you need blower

any thoughts?

Connect stationary bicycle to blower - get exercise and blow job at same time....

Gooserider (ducking)