How long of dust collection runs can I have and what size?

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Forum topic by CanuckEh posted 01-26-2016 04:59 PM 677 views 0 times favorited 6 replies Add to Favorites Watch
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4 posts in 1318 days

01-26-2016 04:59 PM

Topic tags/keywords: dust collection question

5” General Intl. dust collection 1.5 hp and 1050 cfm
I am trying to figure out the size of runs and how long they can be.
I want to set my system out side in a lean to that is protected from the elements and will have air from the building to keep it heated. I will use 5” metal duct and run it along the ceiling with various drop downs to my tools.
All corners will be long radius 90’s .
Services tech for General said only 10’, the store said 20’ then reduce by an inch every 20’.
Looking for right info.
Also General has the same machine with with a 3hp motor. I am wondering if I could switch the motors and increase my cfm?

6 replies so far

View Andre's profile


1785 posts in 1770 days

#1 posted 01-26-2016 06:20 PM

Not sure where you live but you will need to return that air into the shop (Heated shop?) some how? I have the same general unit and ran all my ducts in 4” PVC, blast gates for all outlets, 1 run against wall and the other up and over the roof for the tablesaw and jointer which is well over 20feet with no problems at all. Drop in and take a look if you are in the area!

-- Lifting one end of the plank.

View RobS888's profile


2406 posts in 1809 days

#2 posted 01-26-2016 06:21 PM

I have a Delta DC with similar specs to yours, 5”outlet as well. I have it in a closet under the stairs and 2 4” inch hoses to a 55 gallon plastic tub I use as a separator, then 2 separate 4” lines coming out. One goes to my wife’s lathe, maybe 23” altogether with a 3 street Ts. The other goes about 24 feet across the basement to the garage with several direction changes, 7 feet down the garage wall then part way across the floor between the table saw and out-feed table.

My dust collection is pretty good for the table saw (saw stops are a bit harder to pull from the bottom), I have a 15’ flex hose on a joiner/planer that I attach to the the portion between the table saw and out-feed table. That works very well and seems to get everything from the joiner/planer. I think that maybe 45’ or 50’ to the joiner/planer from the separator. Then 6 feet to the actual DC. I use the thinner SW plastic for the runs.

Hope that helps.

-- I always suspected many gun nuts were afraid of something, just never thought popcorn was on the list.

View jusfine's profile


2422 posts in 2890 days

#3 posted 01-26-2016 06:28 PM

My Oneida cyclone sits on the main floor of my barn, shop is in the loft and I have no return air into the shop.

In the -30 winter days when the DC is running, it does ask more of the heater, but it has not been an issue over 12 years.

Sorry I can’t help much with your duct runs, I do have much more length than was recommended for mine off of my 7” main, but have a blast gate at each entry point into the shop (my metal duct runs are under the floor and come through at each machine).

I would recommend you run as big as you can to match the size of the machine; for instance, if you have a planer that has a 5” outlet, run 5” to it and stay as close to the collector as you can. Or reduce as close as you can to the machine. Not technical, but that should get you the best suction.

All the best!

-- Randy "You are judged as much by the questions you ask as the answers you give..."

View Fred Hargis's profile

Fred Hargis

4951 posts in 2458 days

#4 posted 01-26-2016 07:39 PM

Just a comment about the larger motor. You impeller is turning 3600 RPM (+/-) with a 1.5 HP. Now, if you change it to a 3 HP motor it will still turn at 3600 RPM (+/-), so unless you get a larger impeller the larger motor will not increase your air flow.

-- Our village hasn't lost it's idiot, he was elected to congress.

View CanuckEh's profile


4 posts in 1318 days

#5 posted 01-31-2016 03:06 PM

Thx for the response on my ?,s. That will help greatly. Up north for a couple of week and when I get home I will be able to make my adjustments.

View sawdustdad's profile


354 posts in 849 days

#6 posted 01-31-2016 03:19 PM

I have a 2hp collector and have 40 feet of 6 inch metal duct, carefully taped to minimize leaks. 5 inch drop to the planer’s separator, and 4 inch drops to the other machines. Works great.

-- Murphy's Carpentry Corollary #3: Half of all boards cut to a specific length will be too short.

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