Jump to content

DIY kiln exhaust fan burn-off issue


KatC

Recommended Posts

Hello! I made my own hood which I hooked up to a squirrel cage fan —which vents out the top of my garage .... worked great until it started squealing... we took it apart to discover that it had a gray coating on the moving parts ... assuming it is from the burnoff from glaze firing. We cleaned the fan up but very quickly it was coated again. I can’t $wing buying a proper vent system at this time but I have several loads I have to fire... so... before I purchasing (and kill another squirrel cage fan..... wonder if anyone has any solutions to protect the fan (a filter, perhaps?)  or a better diy  vent system.  Thanx in advance for any suggestions .

Link to comment
Share on other sites

Hi Kat!

Your hood pulls from the area over the kiln, yes? ...hence, not directly connected to the kiln? Just curious.

I repurposed a squirrel cage (bathroom vent) fan as well, it's connected to (also repurposed) propane patio heater hood; the fan is still running great after about twelve firings...

Is the fan failing, or just dirty? ...oh, "squealing" ...that sounds like failure. How hot does the fan get?

 

I also have a direct vent connected to the bottom of the kiln; it pulls superheated gasses from the kiln through a small hole, which is mixed with ambient in a mixing box before it all goes through its fan.

I'm not seeing accumulation in either system, will check them again, however...

 

Checked, there's some dust on the fan blades, about what one would expect - check out bathroom and kitchen fans that get run a lot. That said, if the conditions are too dusty for a fan to last, perhaps too dusty for the potter as well.

My mid-range (it was cheap) repurposed bathroom fan is in a sheet metal housing, the attached hose is metal, and the hood is aluminum - the assembly definitely gets warm, very likely over the operating temp on the fan, however, perhaps not by much, for housed in an Arizona attic in late July. The metal does shed heat readily as well. Any road, if the fan gives out, the next one will be mounted well away from the hood, draw much more air, so it works better and I can add cool air upstream the fan. Size such that cool air can be added upstream the fan.

Link to comment
Share on other sites

Is the fan close to the heat source of many feet away?The homemade system should work fine  if it's designed well.

Back to the grey matter is that possibly from the hood  or pipe that gets hot??Grey stuff in exhaust sound strange to me.

The fan needs to back far enough not to get super hot. (it was not painted grey by chance?)

Link to comment
Share on other sites

Thank you all!   

I do think the fan is dying (I probably shortened it's life)...I used a big galvanized pail for the hood---so the grey stuff could have been zinc coating the fan...???..... ....hmmmm . The pipe from hood to fan is about 5' away...but, the hood never gets hot to  the touch...so, don't think (?) it is excessive heat  causing issues....and nothing was painted (or made pretty in any way! lol) . I am thinking about putting a very cheap furnace filter somewhere  in the  vent connections (before the fan) to see if that helps the new fan I am ordering--while also making sure it doesn't impeded flow or tax the fan motor.  If the filter turns gray, I'll  find non-galv pail for the hood...........worth a try! Thanx All  for your input! 

 

If at first you don't succeed, keep on sucking til you do succeed!

(Three Stooges)

Link to comment
Share on other sites

1 hour ago, KatC said:

Thank you all!   

I do think the fan is dying (I probably shortened it's life)...I used a big galvanized pail for the hood---so the grey stuff could have been zinc coating the fan...???..... ....hmmmm . The pipe from hood to fan is about 5' away...but, the hood never gets hot to  the touch...so, don't think (?) it is excessive heat  causing issues....and nothing was painted (or made pretty in any way! lol) . I am thinking about putting a very cheap furnace filter somewhere  in the  vent connections (before the fan) to see if that helps the new fan I am ordering--while also making sure it doesn't impeded flow or tax the fan motor.  If the filter turns gray, I'll  find non-galv pail for the hood...........worth a try! Thanx All  for your input! 

 

If at first you don't succeed, keep on sucking til you do succeed!

(Three Stooges)

Most hood designs would be in the 400-500 cfm range which would get rid of most of the heat but also bring in a lot of room air or dilution air if you will, which helps cool the fan motor itself. Most fans don’t like operating 140 degrees and higher so it’s likely the heat is killing this thing.

400 cfm is likely equivalent to running 4-6 bath type fans, Btw. I have never measured a bath fan yet that could discharge 100cfm contninously.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.