Exhaust Hose Diameter and Recommendations?

[yukoncornelius]

Interesting huky girl...

I have a general question regarding any type of exhaust off that hood, and I"m sure this is probably physics of some sort - when I connect the hose, I believe it almost creates too much backpressure and unless I'm crazy, more air is leaking out the sides of where the tray sits on top of the fan.  If I remove the hose, the air flow coming out of the hood opening is immense.  During my first roast, I was kinda bugging out cause I felt alot of air coming out the sides and I'm pretty sure it filled my apartment.  I have a lasko high powered fan which is fantastic at directing airflow.  I almost want to run no piping off the exhaust hood and let the fan direct it out my door. 

Is something wrong with my setup that backpressure is being created and air is leaking out the sides of the fan?

[edtbjon]

Any pipe, and especially flex pipes does introduce drag (or back pressure, depending on from your viewpoint). A leak on the junction between the fan and the bowl is easy to deal with, just seal it. Even though the air/smoke still feels hot, it have already cooled down to about 70C/160F, so you can even make a paper gasket.
The top of the fan is another story. Even though the fan should suck the air/smoke down to the bowl, I'd see to that too. The idea here is to make the exhaust system from the roaster down to the fan as sealed as possible and thus as effective as possible. I do believe (... know for sure that the J pipe system is much better in that regard. The hatch/damper on top of the T does leak quite a lot.

[hankua]

more air is leaking out the sides of where the tray sits on top of the fan.

Try wrapping that junction with foil tape.

There are a number of different hacks for the "issue" or poor design. I think in the very original setup there was no dedicated exhaust. My solution was to cut some paper gaskets. Some of the others were rubber gaskets, foil, inline duct fan w/4' pipe, sawdust chaff collector, etc.

https://www.hukyforum.com/index.php/topic,785.msg8627.html#msg8627