A or B

[cmayna]

Per the following quick sketch, I'm considering making a more permanent vent set up for my MES40 which will reside inside my shop. Total length of the vent will be 4+ feet. Is there an advantage of going either A or B? This is looking at the smoker with the vent going out thru the exterior wall. Thus A will have 3 right angle elbows before it passes thru the wall, while B would have 2 right angle elbows. Which is better especially when thinking about creosote accumulation and drainage? I'm thinking A which would have a lower horizontal section which I could add some seepage holes for any possible creosote moisture.

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• cmayna
• Mar 7, 2016

 

[dirtsailor2003]

Every corner creates more resistance. Our HVAC guys always try and use as few turns as possible, and as shallow of an angle as possible.

 

[dirtsailor2003]

Forgot I vote for B

 

[SmokinAl]

I agree "B".

Al

 

[mr t 59874]

Consider using B and forget the seepage holes as they would not help in the vertical pipe and may influence the draft. I place a can under the outlet pipe in my 22cf cold smoker to catch any drippings.

T

 

[cmayna]

Case, For B, I wonder if I can eliminate the horizontal stretch and just come off the smoker with a 45 degree elbow heading up the horizontal that will be going through the wall.   This would help the shallow angle goal but this gives me no horizontal piece to help prevent creosote draining back into the smoker, except for the piece going through the wall. 

 

[dirtsailor2003]

 
Case, For B, I wonder if I can eliminate the horizontal stretch and just come off the smoker with a 45 degree elbow heading up the horizontal that will be going through the wall.   This would help the shallow angle goal but this gives me no horizontal piece to help prevent creosote draining back into the smoker, except for the piece going through the wall. 

I don't see why not.

 

[daveomak]

If the room where the smoker is, is not heated, the exhaust extension could cool the exhaust and stop all or some of the air flow...

 

[jted]

Dirtsailer is right . All bends 45's and 90's do create resistance. Your  exhaust will drain black nasty liquid back into your smoker depending on the air temps. Is it creosote I am not sure but it is commonly called that. Because of that Having a extra 90 or 45 will allow you to drain it off. I have also thought of a catch pan suspend from the vent. I would vote for A. What are you out 4.00 in the cost of a aluminum 90.  Just my opinion once again.   Jted

 

[eatlarge]

Being in the HVAC trade, I'd go with (2) 45's up and over with a 90 out. Best possible air flow IMO. 

 

[cmayna]

Thanks for the replies.  Keep in mind that once I go thru the wall, I will extend out maybe 10" and then 90* up clearing the roof.   Dave, no the shop is not heated.  Is the issue because of the length of the exhaust and being cold? 

What I'd hate to encounter is this not working after I punched a 4" hole thru the wall.  Argh!

 

[daveomak]

The section of pipe in a cold room will form a "cold dam"....   which is or can be a section of cold air in the pipe that has heavy cold air in it that stops the air flow....  
Since the pipe is not pressurized, it is a very common thing....   I have seen cold dams used to one's advantage...  to stop the infiltration of air from another space....