Bradley's Got a New Home

[Rainmaker]

I moved Bradley into his winter quarters so he (and more importantly I) are out of the rain for the winter.



I took off the  vent closure because it wouldn't fit in the aluminum housing.  However, I'm currently doing a brisket and found out that was a mistake.  The cabinet temp wouldn't get over 175.  So I took the tape off and reattached the vent closure and partially closed it.  Sure enough I can now get the temp up to the 220 range where I want it.  I was surprised that the vent being wide open would have such an effect on the cabinet temp. Bradley is in an unheated glass sunroom.  Outside temp last night was about 5 deg C (41 F).
I have found that I will be able to adjust the vent before I start smoking, tape during the smoke portion and then remove the tape and adjust the vent if needed.

[mikeradio]

You should be able to open and close the vent from inside the smoker and not have touch
the tape.

Great job on the install.

[Rainmaker]

You are right, but I'd have to bend the handle on the vent up so it didn't catch.  Suppose I could do that.

[punchlock]

Do you notice any condensation issues with this set in the cold weather? I was going to do something similar but I was worried that an exhaust fan would be needed to draw away potential condensation.

[beefmann]

great looking install, love it

[BuyLowSellHigh]

An option might be to put an adjustable damper just below the flex hose.  You can usually find those at a good hardware store and they don't cost much.

If you are doing things like brisket, I trust you have a plan should you ever get a grease fire going inside .  It's not likely, but it can happen,  Just thinking it would be best to have a pre-thought plan.

[classicrockgriller]

Do you notice any condensation issues with this set in the cold weather? I was going to do something similar but I was worried that an exhaust fan would be needed to draw away potential condensation.

If you do you can use the top shelf with a pan to catch the condensation drips.

[Rainmaker]

Do you notice any condensation issues with this set in the cold weather? I was going to do something similar but I was worried that an exhaust fan would be needed to draw away potential condensation.

I haven't noticed any condensation yet.  The pipe is pretty short. 

[classicrockgriller]

I did read that and was kinda surprised to see that,

but I have never vented my exhaust like this before.

So I'm not sure what effect the vent hose has on the

vent setting. Arnie might know some info in that he did

this once.

Just one thing you might want to consider. The outside

vent might need to be facing down like a ddryer vent to

keep wind from blowing back into the smoker. You may

already have that but I couldn't see on the otherside of

the wall. Also IF you start getting condensation back in

the Cabinet, you may want to turn your hose as soon as

you can past the hose attachment and angle it down.

[BuyLowSellHigh]

I'm trying to figure this out.  Vent wide open, temp won't go above 170.  Vent 3/4 open and the temp goes to 220?  I have never heard of the temp going up in the tower by closing down the vent, even 1/4.  Noticed you have a PID.  Were you controlling the temp with the PID or relying on the door gauge?  Were you testing or did you have something in the smoker?

I promise I'm not being critical.  I'm just trying to understand what's going on.

BLSH, CRG, anybody got an idea? 

Ky, you raise a really good question.  Unfortunately, I don't think the answer is real simple.  My SWAG is that it depends on the amount of moisture being released from whatever is being cooked.  If it weren't for the moisture you would expect that a more closed vent would result in higher temps, or higher temps being reached more easily with less power consumption.  However, if  you have a source of increasing moisture content inside, then the rising moisture levels (humidity) inside a Bradley appear to fight temperature increases, so chicken, for example, which tends to release a lot of moisture, works better with an open vent.  Now comes the complicated part -- if what you are cooking has lost most of the water it is going to give up, then after that point the open vent is probably going to make it harder to raise temps or, at least, require more power to do so (heating element on longer).  So I believe the key here is where you are in the cooking cycle and how much water is being given up by what's in the cabinet.  Something like a brisket will release a fair amount of moisture up into it's characteristic stall, then beyond that the water release will drop off substantially.  Initially it will probably be easier to raise and hold temps with a fairly open vent, then after the stall breaks a more closed vent will probably help keep temps higher.

[squirtthecat]

I'm with CRG on the 'outside vent'.. Perhaps it is a flapper dryer vent that is closed.   Or, perhaps it is wide open, and there is a stiff wind outside - drawing the heat right out of the OBS.

[Mr Walleye]

I would think it's as basic as "heat rises".

The longer the vertical run on the pipe, the greater the "draw" there is. What I suspect is happening is the draw that is created from the vertical run of the vent pipe is literally vacuuming the heat out of the cabinet. This is virtually what I discovered when venting mine, although mine is a powered vent. The solution I came up with can be seen in the photo.



Mike

[ArnieM]

I put a 6 inch stack on my OBS and modified the vent as can be seen in the following pic.  I just should have removed it and thrown it away because I always smoke wide open.

[RAF128]

My installation in the garage is not unlike Rainmakers.   I was concerned about adjusting the vent so I simply cut the tin along the bottom to allow for the movement on the adjusting lever.   I always run mine wide open but like to keep it closed when the smoker is not in use.

[BuyLowSellHigh]

The original pic shows an OBS with an Auber PID, so I assume the Auber is in control.

It could be a simple as what CRG and others have suggested - too much "forced" convection based upon how the vent is terminated.  But, here's the funny thing about heat vs. temp (Caney might be a good one on this).  The Auber controls the application of heat based upon temp.  Depending on where the heat (energy) is going and how the heat is being consumed temperature may not increase even though more heat (or max heat) is being applied. 

The simple example is boiling water.  It takes a surprising amount of heat energy to convert water from a liquid to a gas.  In an open system at 1  atmosphere of pressure applying more heat won't raise the temperature of the water or the steam, it will just make the conversion faster, meaning the water boils off faster. 

When you add that big meat load to the Bradley getting the temp back up isn't just a matter of warming the meat, it's a matter of heat consumption to do the work of vaporizing the water that is being released as the IT of the meat rises.  Whatever is in control can be calling for max heat and the element is full on, but temps don't rise because the energy is being used to do other things.  The same thing happens in the classic stall - the IT doesn't increase because the heat is being used to convert collagen to gelatin, a conversion that sucks up the energy that is being absorbed without an increase in temperature.  Once that conversion is largely complete then temps rise again.