After a lot of shopping around and reading reviews, I went with this one:
High Velocity Inline Duct Fan-6" https://www.amazon.com/dp/B002EC01XS/?tag=skimlinks_replacement-20
530 cfm I expect it to be more than I need but I have always gone with the mantra "Buy big or buy twice". Also, even though my run is only about 8' I really don't want ANY moisture condensing and dripping back down... Figured this would push everything out before it has a chance to cool/condense
Plus thats under my air makeup requirement.
How did you determine your air makeup requirement. It is this piece that has me puzzled and reluctant to pull the trigger.
I only need about 220 cfm based on wattage of my boil coil.
How is the noise level on that Tjernlund M-6 fan? Seems like the best fan as far as power/cost. I just want to get something that's going to for sure be strong enough to get the job done.
Glad I could help! I spent many hours searching for a decent looking hood to use for a centrifugal inline fan and stumbled across a mixing bowl.
Here are some links of what I used:
30 qt mixing bowl: http://www.foodservicewarehouse.com/update-international/mb-3000hd/p1457355.aspx
MTN Gearsmith 4" Inline Fan: http://www.amazon.com/dp/B004ZTJJ5Y/?tag=skimlinks_replacement-20
To OP, are you still happy with the 4" fan, or would you do 6" looking back? Ready to pull the trigger!
How is the noise level on that Tjernlund M-6 fan?
I love it but in our record cold night last night I did have to wedge a blanket up in there to stop cold air from blowing into the house.
I have what looks like the 8" version of this fan and at max speed (770 CFM), it can be a bit loud. Luckily I have never had to run it at full speed and keep it at around 40% with a speed controller and the noise is not bad at all. I am using this speed controller http://www.amazon.com/gp/product/B003URBQ1M/?tag=skimlinks_replacement-20
You need to get something like this for the outside of the vent. http://www.amazon.com/dp/B0049I6LL6/?tag=skimlinks_replacement-20
Something looks familiar in this months Brew Your Own magazine.
sorry, one more question. Is there a way to figure out how many CFM I need based on the wattage of the boil element, the duct size and the number of elbows in my vent line? I'm just curious.
Stickyfinger, you take the element wattage and divide it by 17.6 to get your cfm required. For duct size i found a few charts but they are all for fans below 125 cfm but it will give you an idea of how elbows along duct size and length will affect your system.
http://resaveguide.lbl.gov/step-6-duct-design