Argh

[Pcott]

Just finished my top hat build. I used PVC plastic for the actual ring, and my top hat is 6.5" high with a 4" inlet and outlet. It is 18" in diameter. I am losing massive amounts of suction....no idea why. Could it be too high? Air leaks?
Help please.

[phil (admin)]

What kind of DC are you connected to?

Have any pics?

[Pcott]

Connected to 1.5 HP steel city with 4 in. pipe.

[Pcott]

Anyone? Any help would be appreciated.

[phil (admin)]

Post pictures of what you've got.

It could be a lot of things.  But a picture or two will answer many concerns.

[Pcott]

Here are a couple of admittedly poor pics. The band is made of pvc, set in a groove in the mdf lid and base. the intake hole is set in a piece of oak. with a 4" hole. the output is also 4". The band is around 6.5-7" tall.
Hope this helps.

Sorry they are so dark.

[phil (admin)]

Unfortunately, the two pics don't help me determine the loss in CFM.

But it does look like the drop slot doesn't hug the wall of the separator?

Without better pics all I can tell you is, check for leaks, and, there is no free lunch.  Any separator will put a hit on your CFM.

[Pcott]

I will move the walls closer to the slot. My next question is, is it too high?

[phil (admin)]

I will move the walls closer to the slot. My next question is, is it too high?

Nope.  Height is not a problem.  In terms of CFM drops, higher is better (higher causes less drop).

[Pcott]

One other question. Is the size and orientation of the outlet hole a possible issue?

[phil (admin)]

Should be centered.  For best separation, it should extend below the top about 1/2 the diameter of the fitting.  Should be airtight.  That is about it.

[Rick T]

Pcott, IIRC the Steel City 1.5 hp unit can move a lot of air. Does it not have a 6" dia flex hose between the impeller housing and filter ring and at least a 5" or maybe even 6" dia port into the impeller housing?? If that is the case, and if you have positioned the top hat and collection pail beside the DC, you can go bigger than the 4" line. I use 5" dia flex hose equipment to Top hat and Top Hat to impeller housing and that seems about right based on air flow and velocity for my 1.5 HP Delta 50-760 which is equipped with a Wynn pleated filter. The 5" hose is @ 50% larger x-sectionally than a 4" hose. I also replaced the port into my TS with a 5" HVAC fitting so there's no bottle neck.