Fan or power vent

[slrpro02]

I am in the process of Modding my OBS, I have everything I need to put in the second element including the new on off switch. I was going to put in a fan. however I see some of you using a power vent. My question is should I put in the fan or get the power vent or both?

[beefmann]

depends on where the Smoker is located, if it is in a garage or basement i would go with a vent  right above the  smoker, if it is  outside, why  would you  need  either?

[slrpro02]

What I meant was A fan for circulation on the inside of the OBS.

[TedEbear]

Does the power vent draw air out of the smoker?  If so that's not something I'd recommend since you want the smoke in the chamber as long as possible.  If the power vent replaces the manual vent on top and just circulates the air around would it also block moisture from escaping, sort of like totally closing the manual vent?  That would not be a good thing.

I'm nearly finished with my OBS dual element, PID and fan conversion.  I decided to go with a Dayton 4M079 fan and two axial flow 2.5" fan blades.  They are rated for 45cfm.  One blade will be on the outside of the smoker to act like a heatsink.  I will have the fan wired to the high alarm output of the PID controller so that it comes on when the chamber temp gets to 100*F or higher and stays on after that point.

[muebe]

What I meant was A fan for circulation on the inside of the OBS.

So that would make the OBS into a convection smoker? Sounds like a good mod. But how does that work with it having a vent opening? And how does it affect the smoke?

[slrpro02]

TedEbear
              Now that sounds like a good idea, but what if the PID quit working. Could you add a always on switch to it? that way you could turn the fan on when ever you wanted.

muebe
          The fan circulates the smoke & heat within the chamber

[beefmann]

here is what i did with my smoker with a heater and blower.

http://forum.bradleysmoker.com/index.php?topic=17329.0

then i found out that the blower removed to much heat off the  smoke generator so I made a timer and pid controller that  switches from a cold smoke to cooking, when the  timer  switches to the cook it also turns on the blower and applies  power to the relay of the heater and the  pid controls the relay.

http://forum.bradleysmoker.com/index.php?topic=17304.0

this might be what you  are looking to do .. or a variation

[Habanero Smoker]

I'm not sure if you seen the plans for the Circulation Fan modification. If you have not seen the plans click on the below link:

Circulation Fan

[TedEbear]

TedEbear
              Now that sounds like a good idea, but what if the PID quit working. Could you add a always on switch to it? that way you could turn the fan on when ever you wanted.

Sure, you could wire the fan to be controlled by a switch if you wanted.  I have mine wired to the high alarm output of the PID so that there would not be so many switches and things on the smoke generator box and it would come on automatically soon after I start the smoker.  I've seen some DIY projects that look like the console of a jumbo jet on their front panel and I wanted mine to be externally simple. 

I re-wired the little round power indicator light on the smoke generator box to come on only when the fan is running, or at least whenever power is being sent to the fan.  I have a lighted on/off switch for the PID controller power, so I didn't see the need to have two lights that did basically the same thing. The little light on the tower faceplate still comes on when the heating elements are on.  The slider heater control switch no longer does anything.

[classicrockgriller]

I have circulation fans in my Bradley and I use a power vent (thanks Mikeradio)

in my big smoker. When I start my sausage to "dry" (big smoker) I use the power

vent to help remove the moisture from the cabinet. I turn it off during the smoke

time. (I like smoke) And depending on the humidity outside (I live where the Texas

Gulf coast has a humidity influence on me) I may raise the power vent on a

couple of washers and off set it from my top vent during the cooking cycle.

As far as the fans in my Bradley, I have not seen an advantage to run them

unless i am drying jerky. (And I have tried them out a bunch)